Jeep liberty 2002 2005 fuel system

FUEL SYSTEM

TABLE OF CONTENTS

page page

FUEL DELIVERY . . . . . . . . . . . . . . . . . . . . . . . . . . 1 FUEL INJECTION . . . . . . . . . . . . . . . . . . . . . . . . 29

FUEL DELIVERY

TABLE OF CONTENTS

page page

FUEL DELIVERYDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 2OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3DIAGNOSIS AND TESTING - FUEL

PRESSURE LEAK DOWN TEST . . . . . . . . . . . 3STANDARD PROCEDURE - FUEL SYSTEM

PRESSURE RELEASE . . . . . . . . . . . . . . . . . . . 4SPECIFICATIONS

FUEL SYSTEM PRESSURE . . . . . . . . . . . . . . 5TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SPECIAL TOOLSFUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . 6

FLOW MANAGEMENT VALVEDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 6OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . 7

FUEL FILTERDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 7REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . 8

FUEL LEVEL SENDING UNIT / SENSORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 9OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9DIAGNOSIS AND TESTING - FUEL LEVEL

SENDING UNIT . . . . . . . . . . . . . . . . . . . . . . . . 9REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 10

FUEL LINESDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 10

QUICK CONNECT FITTINGDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 10STANDARD PROCEDURE - QUICK-CONNECT

FITTINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . 10FUEL PRESSURE REGULATOR

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 13

OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 14REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 14

FUEL PUMPDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 15OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 15DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - FUEL PUMPCAPACITY TEST . . . . . . . . . . . . . . . . . . . . . . 15

DIAGNOSIS AND TESTING - FUEL PUMPPRESSURE TEST . . . . . . . . . . . . . . . . . . . . . 15

DIAGNOSIS AND TESTING - FUEL PUMPAMPERAGE TEST . . . . . . . . . . . . . . . . . . . . . 16

FUEL PUMP MODULEDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 18OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 18REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 19

FUEL RAILDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 21OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 21REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 24

FUEL TANKDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 24OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 24REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 27

FUEL TANK CHECK VALVEDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 28OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 28REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 28

INLET FILTERREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 28

KJ FUEL SYSTEM 14 - 1

FUEL DELIVERY

DESCRIPTIONThe fuel delivery system consists of:• the 2–section fuel pump module containing the

electric fuel pump, fuel pressure regulator, fuel gaugesending unit (fuel level sensor) and a fuel filterlocated inside the lower section of pump module

• fuel tubes/lines/hoses• A separately mounted main fuel filter

• quick-connect fittings• fuel injector rail• fuel tank• fuel tank filler/vent tube assembly• fuel tank filler tube cap• accelerator pedal• throttle cableCertain fuel delivery components can be found in

(Fig. 1).

Fig. 1 FUEL DELIVERY COMPONENTS1 - FUEL TANK 10 - EVAP CANISTER2 - FUEL TANK STRAPS 11 - FLOW MANAGEMENT VALVE3 - FUEL PUMP MODULE LOCK RING 12 - FRESH AIR TUBE4 - CHECK (CONTROL) VALVE 13 - HOSE SLEEVE5 - FUEL PUMP MODULE FLANGE 14 - FUEL FILTER6 - FUEL FILL HOSE 15 - LEAK DETECTION PUMP7 - FRESH AIR FILTER 16 - HEAT SHIELD8 - FUEL FILL CAP/BEZEL 17 - SKID PLATE9 - FUEL FILL TUBE

14 - 2 FUEL DELIVERY KJ

OPERATIONFuel is picked up in the fuel tank by the fuel pump

module. This module is located on the bottom of thefuel tank.

A fuel return system is provided within the fuelpump module using check valves. A separate fuelreturn line from the engine to the tank is not used.

The fuel pressure regulator and the main fuel filterare not combined. They are separate items.

The fuel tank assembly consists of: the fuel tank,fuel pump module assembly, fuel pump module lockring/gasket, ORVR components. Refer to 25, Emis-sion Control System for ORVR information.

A fuel filler/vent tube assembly using a pressure/vacuum, 1/4 turn fuel filler cap is used. The fuelfiller tube contains a flap door located below the fuelfill cap. A one-way check valve is installed into thetanks fuel fill fitting.

Also to be considered part of the fuel system is theevaporation control system and ORVR system. Thisis designed to reduce the emission of fuel vapors intothe atmosphere. The description and function of theEvaporative Control System is found in 25, EmissionControl Systems.

Both fuel filters (mounted to front of fuel tank, andinside the bottom fuel pump module) are designed forextended service. They do not require normal sched-uled maintenance. The bottom section of the fuelpump module (with included filter) should only bereplaced if a diagnostic procedure indicates to do so.Also, the fuel filter mounted to the front of the fueltank should only be replaced if a diagnostic proce-dure indicates to do so.

DIAGNOSIS AND TESTING - FUEL PRESSURELEAK DOWN TEST

Use this test in conjunction with the Fuel PumpPressure Test and Fuel Pump Capacity Test.

Check Valve Operation: The electric fuel pumpoutlet contains a one-way check valve to prevent fuelflow back into the tank and to maintain fuel supplyline pressure (engine warm) when pump is not oper-ational. It is also used to keep the fuel supply linefull of gasoline when pump is not operational. Afterthe vehicle has cooled down, fuel pressure may dropto 0 psi (cold fluid contracts), but liquid gasoline willremain in fuel supply line between the check valveand fuel injectors. Fuel pressure that hasdropped to 0 psi on a cooled down vehicle(engine off) is a normal condition. When the elec-tric fuel pump is activated, fuel pressure shouldimmediately (1–2 seconds) rise to specification.

Abnormally long periods of cranking to restart ahot engine that has been shut down for a shortperiod of time may be caused by:

• Fuel pressure bleeding past a fuel injector(s).

• Fuel pressure bleeding past the check valve inthe fuel pump module.

(1) Disconnect the fuel inlet line at fuel rail. Referto Quick Connect Fittings for procedures. On someengines, air cleaner housing removal may be neces-sary before fuel line disconnection.

(2) Obtain correct Fuel Line Pressure Test AdapterTool Hose. Tool number 6539 is used for 5/16” fuellines and tool number 6631 is used for 3/8” fuel lines.

(3) Connect correct Fuel Line Pressure TestAdapter Tool Hose between disconnected fuel lineand fuel rail (Fig. 2).

(4) Connect the 0-414 kPa (0-60 psi) fuel pressuretest gauge (from Gauge Set 5069) to the test port onthe appropriate Adaptor Tool. The DRBt III ScanTool along with the PEP module, the 500 psipressure transducer, and the transducer-to-testport adapter may also be used in place of thefuel pressure gauge.

The fittings on both tools must be in goodcondition and free from any small leaks beforeperforming the proceeding test.

(5) Start engine and bring to normal operatingtemperature.

(6) Observe test gauge. Normal operating pressureshould be 339 kPa +/–34 kPa (49.2 psi +/–5 psi).

(7) Shut engine off.

Fig. 2 CONNECTING ADAPTER TOOL—TYPICAL1 - VEHICLE FUEL LINE2 - TEST PORT “T”3 - SPECIAL TOOL 6923, 6631, 6541 OR 65394 - FUEL PRESSURE TEST GAUGE5 - FUEL LINE CONNECTION AT RAIL6 - FUEL RAIL

KJ FUEL DELIVERY 14 - 3

FUEL DELIVERY (Continued)

(8) Pressure should not fall below 30 psi for fiveminutes.

(9) If pressure falls below 30 psi, it must be deter-mined if a fuel injector, the check valve within thefuel pump module, or a fuel tube/line is leaking.

(10) Again, start engine and bring to normal oper-ating temperature.

(11) Shut engine off.(12) Testing for fuel injector or fuel rail leak-

age: Clamp off the rubber hose portion of AdaptorTool between the fuel rail and the test port “T” onAdapter Tool. If pressure now holds at or above 30psi, a fuel injector or the fuel rail is leaking.

(13) Testing for fuel pump check valve, filter,regulator check valve or fuel tube/line leakage:Clamp off the rubber hose portion of Adaptor Toolbetween the vehicle fuel line and test port “T” onAdapter Tool. If pressure now holds at or above 30psi, a leak may be found at a fuel tube/line. If noleaks are found at fuel tubes or lines, one of thecheck valves in either the electric fuel pump, fuel fil-ter or fuel pressure regulator may be leaking.

Note: A quick loss of pressure usually indicates adefective check valve in the pressure regulator. Aslow loss of pressure usually indicates a defectivecheck valve in the bottom of the fuel pump module.The check valves are not serviced separately. Also,the electric fuel pump is not serviced separately.

STANDARD PROCEDURE - FUEL SYSTEMPRESSURE RELEASE

Use following procedure if the fuel injectorrail is, or is not equipped with a fuel pressuretest port.

(1) Remove fuel fill cap.(2) Remove fuel pump relay from Power Distribu-

tion Center (PDC). For location of relay, refer to labelon underside of PDC cover.

(3) Start and run engine until it stalls.(4) Attempt restarting engine until it will no

longer run.(5) Turn ignition key to OFF position.

CAUTION: Steps 1, 2, 3 and 4 must be performed torelieve high pressure fuel from within fuel rail. Donot attempt to use following steps to relieve thispressure as excessive fuel will be forced into a cyl-inder chamber.

(6) Unplug connector from any fuel injector.(7) Attach one end of a jumper wire with alligator

clips (18 gauge or smaller) to either injector terminal.(8) Connect other end of jumper wire to positive

side of battery.(9) Connect one end of a second jumper wire to

remaining injector terminal.

CAUTION: Powering an injector for more than a fewseconds will permanently damage the injector.

(10) Momentarily touch other end of jumper wireto negative terminal of battery for no more than afew seconds.

(11) Place a rag or towel below fuel line quick-con-nect fitting at fuel rail.

(12) Disconnect quick-connect fitting at fuel rail.Refer to Quick-Connect Fittings.

(13) Return fuel pump relay to PDC.(14) One or more Diagnostic Trouble Codes (DTC’s)

may have been stored in PCM memory due to fuelpump relay removal. The DRBt scan tool must beused to erase a DTC.



SPECIFICATIONS

FUEL SYSTEM PRESSURE339 kPa +/- 34 kPa (49.2 psi +/- 2 psi).

TORQUE

DESCRIPTION N-m Ft. Lbs. In. Lbs.

Accelerator Pedal Bracket Mounting Nuts 12 - 105

Crankshaft Position Sensor - 2.4L 28 21 -

Crankshaft Position Sensor - 3.7L 28 21 -

Camshaft Position Sensor - 2.4L 12 - 106

Camshaft Position Sensor - 3.7L 12 - 106

Engine Coolant Temperature Sensor 11 - 96

EVAP Canister-to-Body Bolts 48 35 -

EVAP Canister-to-Canis. Bracket Bolt/Nut 11 - 100

Fuel Filler Hose Clamp at Tank 3 - 30

Fuel Filler Housing-to-Body Screws 2 - 17

Fuel Filter Mounting Nut at Tank 5.5 - 49

Fuel Pump Module Access Plate Nuts 3 - 26

Fuel Rail Mounting Bolts - 3.7L 11 - 100

Fuel Rail Mounting Bolts - 2.4L 28 - 250

Fuel Tank Heat Sheild Nuts 5.5 - 49

Fuel Tank Mounting Strap Bolts 61 45 -

Fuel Tank Skid Plate and Trailer Hitch 88 65 -

IAC Motor Mounting Screws 7 - 60

Leak Detection Pump Mounting Bracket-to-FuelTank Nuts

5.5 - 49

Leak Detection Pump-to-Bracket Nuts 1.2 - 11

Map Sensor Mounting Screws 3 - 25

PCM-to-Mounting Bracket Mounting Screws 4 - 35

Power Steering Pressure Switch 14-22 - 124-195

TPS Mounting Screws 7 - 60

Throttle Body Mounting Bolts 11 - 100

Oxygen Sensors 30 22 -



SPECIAL TOOLS

FUEL SYSTEM

FLOW MANAGEMENT VALVE

DESCRIPTIONThe flow management valve is a part of the ORVR

system. This plastic valve is placed inline betweenthe fuel tank vent fitting and the EVAP canister. It islocated on top of the fuel tank (Fig. 1).

OPERATIONThe flow management valve (Fig. 1) is one of the com-

ponents used in the ORVR system. The valve metersthe flow of fuel vapors to the EVAP canister duringvehicle run and refueling. Pressure from the tank dur-ing refueling opens the main port valve and allowsvapors to enter the EVAP canister. During vehicle run,the vapors are metered through an orifice to the EVAPcanister. It is also used as a liquid separator to keep liq-uid fuel out of the EVAP canister.

REMOVALThe flow management valve is located on top of the

fuel tank (Fig. 1).(1) Four cargo holdown clamps are located inside

the vehicle on the floor of the rear cargo area.Remove the 2 rearward mounted clamps by drillingout the clamp rivets.

(2) Fold carpeting forward to gain access to fuelpump module access plate (Fig. 3).

Fig. 3 ACCESS PLATE1 - FLOORPAN AT REAR2 - FUEL PUMP MODULE ACCESS PLATE3 - NUTS (4)4 - OPENING TO PUMP MODULE

ADAPTERS, FUEL PRESSURE TEST—6539 AND/OR6631

TEST KIT, FUEL PRESSURE—5069

TEST KIT, FUEL



(3) Remove 4 fuel pump module access plate nuts(Fig. 3).

(4) While applying heat from a heat gun, carefullypry up fuel pump module access plate. Take care notto bend plate.

(5) Disconnect flow management valve hose clampand hose (Fig. 4) at pump module fitting. Also discon-nect small recirculation line at top half of manage-ment valve.

(6) Raise vehicle.(7) Disconnect opposite end of flow management

valve hose at EVAP canister (Fig. 1).(8) Remove valve and 2 hoses as an assembly.

INSTALLATION(1) Raise vehicle.(2) Attach 2 large hoses and 1 small line to flow

management valve. Position this assembly to top offuel tank.

(3) Connect valve hose at EVAP canister.(4) Lower vehicle.(5) Attach valve hose and clamp to top of fuel

pump module.(6) Apply silicone sealant to bottom of fuel pump

module metal access plate.

(7) Install fuel pump module metal access plateand 4 nuts. Tighten nuts to 3 N·m (26 in. lbs.)torque.

(8) Position carpet and install 2 new cargo clamprivets.

FUEL FILTER

DESCRIPTIONThe fuel pressure regulator and fuel filter are not

combined on this vehicle. The main fuel filter isattached to the front of the fuel tank (Fig. 1) and is aserviceable/replaceable item. Also refer to Inlet Filterand Fuel Pressure Regulator.

REMOVALThe main fuel filter is attached to the front of fuel

tank (Fig. 1). Three fuel lines are used at filter.Fuel tank removal will not be necessary for

fuel filter removal. Access is from rear cargoarea.

WARNING: THE FUEL SYSTEM MAY BE UNDER ACONSTANT PRESSURE (EVEN WITH THE ENGINEOFF). BEFORE SERVICING MOST FUEL SYSTEMCOMPONENTS, THE FUEL SYSTEM PRESSUREMUST BE RELEASED. REFER TO THE FUEL SYS-TEM PRESSURE RELEASE PROCEDURE.

(1) Release fuel system pressure.(2) Four cargo holdown clamps are located inside

vehicle on floor of rear cargo area. Two of these fourclamps must be removed. Remove 2 rearwardmounted clamps by drilling out clamp rivets.



(5) While applying heat from a heat gun, carefullypry up metal fuel pump module access plate. Takecare not to bend plate.

(6) Clean top of fuel pump module area aroundfuel line connection points.

(7) Disconnect 2 fuel lines at fuel pump module(Fig. 6) by pressing on tabs at side of fitting.

(8) Raise vehicle.(9) Place drain pan under fuel filter.(10) A third fuel line is attached to bottom of filter

(Fig. 7). The disconnection point for this 3rd line isapproximately 1 foot towards front of vehicle. Cleanfuel line connection point before disconnection. Dis-connect by pressing on tabs at side of fitting.

(11) Disconnect 3rd fuel line from body retentionclip. Place a small screwdriver into side of clip andtwist for removal.

Fig. 4 TOP OF FUEL PUMP MODULE1 - LOCK RING2 - ALIGNMENT NOTCH3 - FUEL FILTER FITTINGS (2)4 - ORVR SYSTEM HOSE AND CLAMP5 - FLOW MANAGEMENT VALVE6 - ELECTRICAL CONNECTOR7 - LEAK DETECTION PUMP8 - FUEL TANK CHECK (CONTROL) VALVE9 - FUEL PUMP MODULE (UPPER SECTION)


FLOW MANAGEMENT VALVE (Continued)

(12) Remove filter ground strap at fuel tankmounting strap.

(13) Remove 1 filter mounting nut (Fig. 7) andremove filter.

INSTALLATION(1) Raise vehicle.(2) Position fuel lines on filter towards top of fuel

tank.(3) Position filter to mounting stud on front of fuel

tank.(4) Install filter mounting nut and tighten. Refer

to torque specifications.(5) A third fuel line is attached to bottom of filter.

The connection point for this 3rd line is approxi-mately 1 foot towards front of vehicle. Connect bysnapping together.

(6) Connect 3rd fuel line to body retention clip(snaps in).

(7) Attach filter ground strap to tank mountingstrap.

(8) Lower vehicle.(9) Attach (snap on) 2 filter fuel lines at fuel pump

module fittings.(10) Start engine and check fuel line fittings for

leaks.(11) Apply silicone sealant to fuel pump module

metal access plate.

(12) Install fuel pump module metal access plateand 4 nuts. Tighten 4 nuts. Refer to torque specifica-tions.

(13) Position carpet and install 2 new cargo clamprivets in each cargo holdown clamp.


Fig. 6 FUEL LINES AT PUMP MODULE1 - FUEL PUMP MODULE LOCKRING2 - FUEL LINES TO FUEL FILTER (2)3 - QUICK-CONNECT FITTINGS (2)4 - ROLLOVER VALVE

Fig. 7 FUEL FILTER LOCATION1 - FUEL FILTER2 - 3RD FUEL LINE TO ENGINE3 - FILTER MOUNTING NUT


FUEL FILTER (Continued)

FUEL LEVEL SENDING UNIT /SENSOR

DESCRIPTIONThe fuel gauge sending unit (fuel level sensor) is

attached to the side of the fuel pump module. Thesending unit consists of a float, an arm, and a vari-able resistor track (card).

OPERATIONThe fuel pump module has 4 different circuits

(wires). Two of these circuits are used for the fuelgauge sending unit for fuel gauge operation, and forcertain OBD II emission requirements. The other 2wires are used for electric fuel pump operation.

For Fuel Gauge Operation: A constant currentsource of approximately 32 milliamps is supplied tothe resistor track on the fuel gauge sending unit.This is fed directly from the Powertrain Control Mod-ule (PCM). NOTE: For diagnostic purposes, this12V power source can only be verified with thecircuit opened (fuel pump module electricalconnector unplugged). With the connectorsplugged, output voltages will vary from about0.6 volts at FULL, to about 8.6 volts at EMPTY(about 8.6 volts at EMPTY for Jeep models, andabout 7.0 volts at EMPTY for Dodge Truck mod-els). The resistor track is used to vary the voltage(resistance) depending on fuel tank float level. Asfuel level increases, the float and arm move up,which decreases voltage. As fuel level decreases, thefloat and arm move down, which increases voltage.The varied voltage signal is returned back to thePCM through the sensor return circuit.

Both of the electrical circuits between the fuelgauge sending unit and the PCM are hard-wired (notmulti-plexed). After the voltage signal is sent fromthe resistor track, and back to the PCM, the PCMwill interpret the resistance (voltage) data and senda message across the multi-plex bus circuits to theinstrument panel cluster. Here it is translated intothe appropriate fuel gauge level reading. Refer toInstrument Panel for additional information.

For OBD II Emission Monitor Requirements:The PCM will monitor the voltage output sent fromthe resistor track on the sending unit to indicate fuellevel. The purpose of this feature is to prevent theOBD II system from recording/setting false misfireand fuel system monitor diagnostic trouble codes.The feature is activated if the fuel level in the tankis less than approximately 15 percent of its ratedcapacity. If equipped with a Leak Detection Pump(EVAP system monitor), this feature will also be acti-vated if the fuel level in the tank is more thanapproximately 85 percent of its rated capacity.

DIAGNOSIS AND TESTING - FUEL LEVELSENDING UNIT

The fuel level sending unit contains a variableresistor (track). As the float moves up or down, elec-trical resistance will change. Refer to InstrumentPanel and Gauges for Fuel Gauge testing. To test thegauge sending unit only, it must be removed fromvehicle. The unit is a separate part of the lower fuelpump module section. Refer to Fuel Pump ModuleRemoval/Installation for procedures (remove only theupper section of the fuel pump module). Measure theresistance across the sending unit terminals. Withfloat in up position, resistance should be 20 ohms (+/-5%). With float in down position, resistance should be270 ohms (+/- 5%).

REMOVALThe fuel level sending unit (fuel level sensor) and

float assembly is located on the side of the lower sec-tion of the fuel pump module. The lower section ofthe fuel pump module is located within the fuel tank.

(1) Remove lower section of fuel pump modulefrom fuel tank. Refer to Fuel Pump Module Removal/Installation.

(2) To remove sending unit from pump module, lifton plastic locking tab (Fig. 8) while sliding sendingunit upwards.

(3) Disconnect 4–wire electrical connector (Fig. 9)from bottom of upper section of fuel pump module.Separate necessary sending unit wiring.

Fig. 8 FUEL LEVEL SENDING UNIT1 - LIFT TAB HERE FOR REMOVAL2 - FUEL LEVEL SENDING UNIT3 - LOWER SECTION OF PUMP MODULE


INSTALLATION(1) Connect necessary wiring into electrical con-

nectors. Connect 4–wire connector to upper section ofpump module.

(2) Position sending unit to pump module. Slideand snap into place.

(3) Install lower section of fuel pump module.Refer to Fuel Pump Module Removal/Installation.

FUEL LINES

DESCRIPTIONAlso refer to Quick-Connect Fittings.

WARNING: THE FUEL SYSTEM MAY BE UNDER ACONSTANT PRESSURE (EVEN WITH THE ENGINEOFF). BEFORE SERVICING ANY FUEL SYSTEMHOSES, FITTINGS, LINES, OR MOST COMPO-NENTS, FUEL SYSTEM PRESSURE MUST BERELEASED. REFER TO THE FUEL SYSTEM PRES-SURE RELEASE PROCEDURE.

The lines/tubes/hoses used on fuel injected vehiclesare of a special construction. This is due to thehigher fuel pressures and the possibility of contami-

nated fuel in this system. If it is necessary to replacethese lines/tubes/hoses, only those marked EFM/EFImay be used.

If equipped: The hose clamps used to secure rub-ber hoses on fuel injected vehicles are of a specialrolled edge construction. This construction is used toprevent the edge of the clamp from cutting into thehose. Only these rolled edge type clamps may beused in this system. All other types of clamps maycut into the hoses and cause high-pressure fuel leaks.

Use new original equipment type hose clamps.

QUICK CONNECT FITTING

DESCRIPTIONDifferent types of quick-connect fittings are used to

attach various fuel system components, lines andtubes. These are: a single-tab type, a two-tab type ora plastic retainer ring type. Some are equipped withsafety latch clips. Some may require the use of a spe-cial tool for disconnection and removal. Refer toQuick-Connect Fittings Removal/Installation for moreinformation.

CAUTION: The interior components (o-rings, clips)of quick-connect fittings are not serviced sepa-rately, but new plastic spacers are available forsome types. If service parts are not available, donot attempt to repair the damaged fitting or fuel line(tube). If repair is necessary, replace the completefuel line (tube) assembly.

STANDARD PROCEDURE - QUICK-CONNECTFITTINGS

Also refer to Fuel Tubes/Lines/Hoses and Clamps.Different types of quick-connect fittings are used to

attach various fuel system components, lines andtubes. These are: a single-tab type, a two-tab type ora plastic retainer ring type. Safety latch clips areused on certain components/lines. Certain fittingsmay require use of a special tool for disconnection.

DISCONNECTING

WARNING: THE FUEL SYSTEM IS UNDER A CON-STANT PRESSURE (EVEN WITH ENGINE OFF).BEFORE SERVICING ANY FUEL SYSTEM HOSE,FITTING OR LINE, FUEL SYSTEM PRESSURE MUSTBE RELEASED. REFER TO FUEL SYSTEM PRES-SURE RELEASE PROCEDURE.

Fig. 9 FUEL PRESSURE REGULATOR/SENDINGUNIT ELECTRICAL CONNECTOR

1 - UPPER SECTION OF PUMP MODULE2 - QUICK-CONNECT FITTINGS3 - FUEL PRESSURE REGULATOR4 - 4-WIRE ELECTRICAL CONNECTOR5 - FUEL TANK CHECK (CONTROL) VALVE


FUEL LEVEL SENDING UNIT / SENSOR (Continued)

CAUTION: The interior components (o-rings, spac-ers) of some types of quick-connect fitting are notserviced separately. If service parts are not avail-able, do not attempt to repair a damaged fitting orfuel line. If repair is necessary, replace completefuel line assembly.

(1) Perform fuel pressure release procedure. Referto Fuel Pressure Release Procedure.

(2) Disconnect negative battery cable from battery.(3) Clean fitting of any foreign material before dis-

assembly.(4) 2–Button Type Fitting: This type of fitting is

equipped with a push-button located on each side ofquick-connect fitting (Fig. 10). Press on both buttonssimultaneously for removal.

(5) Single-Tab Type Fitting: This type of fittingis equipped with a single pull tab (Fig. 11). The tab isremovable. After tab is removed, quick-connect fittingcan be separated from fuel system component.

(a) Press release tab on side of fitting to releasepull tab (Fig. 12). If release tab is not pressedprior to releasing pull tab, pull tab will bedamaged.

(b) While pressing release tab on side of fitting,use screwdriver to pry up pull tab (Fig. 12).

(c) Raise pull tab until it separates from quick-connect fitting (Fig. 13).(6) Two-Tab Type Fitting: This type of fitting is

equipped with tabs located on both sides of fitting(Fig. 14). The tabs are supplied for disconnectingquick-connect fitting from component being serviced.

(a) To disconnect quick-connect fitting, squeezeplastic retainer tabs (Fig. 14) against sides ofquick-connect fitting with your fingers. Tool use isnot required for removal and may damage plasticretainer.

(b) Pull fitting from fuel system componentbeing serviced.

(c) The plastic retainer will remain on compo-nent being serviced after fitting is disconnected.The o-rings and spacer will remain in quick-con-nect fitting connector body.

Fig. 10 2-BUTTON TYPE FITTING1 - QUICK-CONNECT FITTING2 - PUSH-BUTTONS (2)

Fig. 11 SINGLE-TAB TYPE FITTING1 - PULL TAB2 - QUICK-CONNECT FITTING3 - PRESS HERE TO REMOVE PULL TAB4 - INSERTED TUBE END

Fig. 12 DISCONNECTING SINGLE-TAB TYPEFITTING

1 - PULL TAB2 - SCREWDRIVER3 - QUICK-CONNECT FITTING


QUICK CONNECT FITTING (Continued)

(7) Plastic Retainer Ring Type Fitting: Thistype of fitting can be identified by the use of a full-round plastic retainer ring (Fig. 15) usually black incolor.

(a) To release fuel system component from quick-connect fitting, firmly push fitting towards compo-nent being serviced while firmly pushing plasticretainer ring into fitting (Fig. 15). With plastic ringdepressed, pull fitting from component. The plas-tic retainer ring must be pressed squarelyinto fitting body. If this retainer is cockedduring removal, it may be difficult to discon-nect fitting. Use an open-end wrench onshoulder of plastic retainer ring to aid in dis-connection.

Fig. 13 REMOVING PULL TAB1 - FUEL TUBE OR FUEL SYSTEM COMPONENT2 - PULL TAB3 - QUICK-CONNECT FITTING4 - FUEL TUBE STOP

Fig. 14 TYPICAL 2–TAB TYPE FITTING1 - TAB(S)2 - QUICK-CONNECT FITTING

Fig. 15 PLASTIC RETAINER RING TYPE FITTING1 - FUEL TUBE2 - QUICK CONNECT FITTING3 - PUSH4 - PLASTIC RETAINER5 - PUSH6 - PUSH7 - PUSH8 - PUSH

Fig. 16 LATCH CLIP-TYPE 11 - TETHER STRAP2 - FUEL LINE3 - SCREWDRIVER4 - LATCH CLIP5 - FUEL RAIL



(b) After disconnection, plastic retainer ring willremain with quick-connect fitting connector body.

(c) Inspect fitting connector body, plastic retainerring and fuel system component for damage.Replace as necessary.(8) Latch Clips: Depending on vehicle model and

engine, 2 different types of safety latch clips are used(Fig. 16) or (Fig. 17). Type-1 is tethered to fuel lineand type-2 is not. A special tool will be necessary to

disconnect fuel line after latch clip is removed. Thelatch clip may be used on certain fuel line/fuel railconnection, or to join fuel lines together.

(a) Type 1: Pry up on latch clip with a screw-driver (Fig. 16).

(b) Type 2: Separate and unlatch 2 small armson end of clip (Fig. 17) and swing away from fuelline.

(c) Slide latch clip toward fuel rail while liftingwith screwdriver.

(d) Insert special fuel line removal tool (Snap-Onnumber FIH 9055-1 or equivalent) into fuel line(Fig. 18). Use tool to release locking fingers in endof line.

(e) With special tool still inserted, pull fuel linefrom fuel rail.

(f) After disconnection, locking fingers willremain within quick-connect fitting at end of fuelline.(9) Disconnect quick-connect fitting from fuel sys-

tem component being serviced.

CONNECTING(1) Inspect quick-connect fitting body and fuel sys-

tem component for damage. Replace as necessary.(2) Prior to connecting quick-connect fitting to

component being serviced, check condition of fittingand component. Clean parts with a lint-free cloth.Lubricate with clean engine oil.

(3) Insert quick-connect fitting into fuel tube orfuel system component until built-on stop on fueltube or component rests against back of fitting.

(4) Continue pushing until a click is felt.(5) Single-tab type fitting: Push new tab down

until it locks into place in quick-connect fitting.(6) Verify a locked condition by firmly pulling on

fuel tube and fitting (15-30 lbs.).(7) Latch Clip Equipped: Install latch clip (snaps

into position). If latch clip will not fit, this indi-cates fuel line is not properly installed to fuelrail (or other fuel line). Recheck fuel line con-nection.

(8) Connect negative cable to battery.(9) Start engine and check for leaks.

FUEL PRESSURE REGULATOR

DESCRIPTIONThe fuel pressure regulator is located on the bot-

tom of the upper section of the fuel pump module.The fuel filter is not combined into the pressureregulator on this model.

Fig. 17 LATCH CLIP-TYPE 21 - LATCH CLIP

Fig. 18 FUEL LINE DISCONNECTION USINGSPECIAL TOOL

1 - SPECIAL FUEL LINE TOOL2 - FUEL LINE3 - FUEL RAIL



OPERATIONThe fuel pressure regulator is a mechanical device

that is not controlled by engine vacuum or the Pow-ertrain Control Module (PCM).

The regulator is calibrated to maintain fuel systemoperating pressure of approximately 339 kPa +/- 34kPa (49.2 psi +/- 5 psi) at the fuel injectors. It con-tains a diaphragm, calibrated springs and a fuelreturn valve.

The main fuel filter is not combined within thefuel pressure regulator as in other Jeept models.Three different fuel filters are used: 1. a serviceable,separate, externally mounted, main fuel filter; 2. anon-serviceable primary filter located on the bottomof the electric fuel pump; 3. a non-serviceable second-ary filter attached to the side of the fuel pump mod-ule.

Fuel Flow: Fuel migrates into the fuel pump mod-ule reservoir through a one-way check valve locatedon the bottom of the module. This check valve pre-vents the reservoir from running empty such aswhen going up or down hills with a low amount offuel in the tank. A primary fuel filter (sock) is locatedat the bottom of the electric fuel pump. Fuel is drawnin through this filter, and up to the electric fuelpump. High pressure fuel (unregulated) is suppliedfrom the electric fuel pump through a high-pressureline to one of 3 fittings on the main fuel filter. If fuelpressure at the pressure regulator exceeds approxi-mately 49 psi, an internal diaphragm within the reg-ulator closes, and excess fuel is routed through asecond fitting on the main fuel filter, and back intothe fuel tank (the fuel pressure regulator is installedinto the return side of the system). Pressure regu-lated fuel is then delivered from the third fitting onthe fuel filter, up to and through the fuel rail, and onto the fuel injectors.

A secondary fuel filter is attached to the side of thefuel pump module. High-pressure from the electricfuel pump causes a siphoning action across a passageconnected to this filter, and fuel is drawn into thefuel pump module reservoir. This is used to help keepthe module reservoir full of fuel.

The fuel pressure regulator also acts as a checkvalve to maintain some fuel pressure when theengine is not operating. This will help to start theengine. A second check valve is located at the outletof the fuel pump module housing. Refer to FuelPump - Description and Operation for moreinformation. Also refer to the Fuel PressureLeak Down Test, and the Fuel Pump PressureTests.

A separate fuel return line from the engine is notused with this system.

REMOVALThe fuel pressure regulator is located in the fuel

tank. It is attached to the bottom of the upper sec-tion of the fuel pump module with a quick-connectfitting (Fig. 19). The fuel pump module is supplied in2 sections (upper and lower). To replace the pressureregulator, the bottom section of the fuel pump mod-ule must be replaced.

(1) Remove upper and lower sections of fuel pumpmodule from fuel tank. Refer to Fuel Pump ModuleRemoval/Installation.

(2) Replace lower section of fuel pump module(includes fuel pressure regulator).

INSTALLATIONThe fuel pressure regulator is located in the fuel

tank. It is attached to the bottom of the upper sec-tion of the fuel pump module with a quick-connectfitting. The fuel pump module is supplied in 2 sec-tions (upper and lower). To replace the pressure reg-ulator, the bottom section of the fuel pump modulemust be replaced.

(1) Replace lower section of fuel pump module(includes fuel pressure regulator).

(2) Install upper and lower sections of fuel pumpmodule to fuel tank. Refer to Fuel Pump ModuleInstallation.




FUEL PRESSURE REGULATOR (Continued)

FUEL PUMP

DESCRIPTIONThe electric fuel pump is located inside of the fuel

pump module. A 12 volt, permanent magnet, electricmotor powers the fuel pump. The electric fuel pumpis not a separate, serviceable component.

OPERATIONVoltage to operate the electric pump is supplied

through the fuel pump relay.Fuel is drawn in through a filter at the bottom of

the module and pushed through the electric motorgearset to the pump outlet.

Check Valve Operation: The bottom section ofthe fuel pump module contains a one-way checkvalve to prevent fuel flow back into the tank and tomaintain fuel supply line pressure (engine warm)when pump is not operational. It is also used to keepthe fuel supply line full of gasoline when pump is notoperational. After the vehicle has cooled down, fuelpressure may drop to 0 psi (cold fluid contracts), butliquid gasoline will remain in fuel supply linebetween the check valve and fuel injectors. Fuelpressure that has dropped to 0 psi on a cooleddown vehicle (engine off) is a normal condition.Refer to the Fuel Pressure Leak Down Test for moreinformation.

The electric fuel pump is not a separate, service-able component.

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - FUEL PUMPCAPACITY TEST

Before performing this test, verify fuel pumppressure. Refer to Fuel Pump Pressure Test.Use this test in conjunction with the Fuel Pres-sure Leak Down Test.

(1) Release fuel system pressure. Refer to FuelPressure Release Procedure.

(2) Disconnect fuel supply line at fuel rail. Refer toQuick-Connect Fittings. Some engines may requireair cleaner housing removal before line disconnection.

(3) Obtain correct Fuel Line Pressure Test AdapterTool Hose. Tool number 6539 is used for 5/16” fuellines and tool number 6631 is used for 3/8” fuel lines.

(4) Connect correct Fuel Line Pressure TestAdapter Tool Hose into disconnected fuel supply line.Insert other end of Adaptor Tool Hose into a gradu-ated container.

(5) Remove fuel fill cap.

(6) To activate fuel pump and pressurize system,obtain DRBt scan tool and actuate ASD Fuel SystemTest.

(7) A good fuel pump will deliver at least 1/10 literof fuel in 7 seconds. Do not operate fuel pump forlonger than 7 seconds with fuel line disconnected asfuel pump module reservoir may run empty.

(a) If capacity is lower than specification, butfuel pump can be heard operating through fuel fillcap opening, check for a kinked/damaged fuel sup-ply line somewhere between fuel rail and fuelpump module.

(b) If line is not kinked/damaged, and fuel pres-sure is OK, but capacity is low, replace fuel filter.Refer to Fuel Filter Removal/Installation for addi-tional information.

(c) If both fuel pressure and capacity are low,replace bottom section of fuel pump module. Referto Fuel Pump Module Removal/Installation.

DIAGNOSIS AND TESTING - FUEL PUMPPRESSURE TEST

Use this test in conjunction with the Fuel PumpCapacity Test, Fuel Pressure Leak Down Test andFuel Pump Amperage Test found elsewhere in thisgroup.

Check Valve Operation: The bottom section ofthe fuel pump module contains a one-way checkvalve to prevent fuel flow back into the tank and tomaintain fuel supply line pressure (engine warm)when pump is not operational. It is also used to keepthe fuel supply line full of gasoline when pump is notoperational. After the vehicle has cooled down, fuelpressure may drop to 0 psi (cold fluid contracts), butliquid gasoline will remain in fuel supply linebetween the check valve and fuel injectors. Fuelpressure that has dropped to 0 psi on a cooleddown vehicle (engine off) is a normal condition.When the electric fuel pump is activated, fuel pres-sure should immediately (1–2 seconds) rise to spec-ification.

The fuel system is equipped with a separate fuelpump module mounted, fuel pressure regulator. Thefuel filter is remotely mounted. The fuel pressureregulator is not controlled by engine vacuum.

WARNING: THE FUEL SYSTEM IS UNDER CON-STANT FUEL PRESSURE EVEN WITH THE ENGINEOFF. BEFORE DISCONNECTING FUEL LINE ATFUEL RAIL, THIS PRESSURE MUST BE RELEASED.REFER TO THE FUEL SYSTEM PRESSURERELEASE PROCEDURE.


(1) Remove protective cap at fuel rail test port.Connect the 0–414 kPa (0-60 psi) fuel pressure gauge(from gauge set 5069) to test port pressure fitting onfuel rail (Fig. 20). The DRBt III Scan Tool alongwith the PEP module, the 500 psi pressuretransducer, and the transducer-to-test portadapter may also be used in place of the fuelpressure gauge.

(2) Start and warm engine and note pressuregauge reading. Fuel pressure should be 339 kPa ± 34kPa (49.2 psi ± 5 psi) at idle.

(3) If engine runs, but pressure is below 44.2 psi,check for a kinked fuel supply line somewherebetween fuel rail and fuel pump module. If line is notkinked, but specifications for either the Fuel PumpCapacity, Fuel Pump Amperage or Fuel PressureLeak Down Tests were not met, replace lower sectionof fuel pump module. Refer to Fuel Pump ModuleRemoval/Installation.

(4) If operating pressure is above 54.2 psi, electricfuel pump is OK, but fuel pressure regulator is defec-tive. Replace lower section of fuel pump module.Refer to Fuel Pump Module Removal/Installation.

(5) Install protective cap to fuel rail test port.

DIAGNOSIS AND TESTING - FUEL PUMPAMPERAGE TEST

This amperage (current draw) test is to be done inconjunction with the Fuel Pump Pressure Test, FuelPump Capacity Test and Fuel Pressure Leak DownTest. Before performing the amperage test, be surethe temperature of the fuel tank is above 50° F (10°C).

The DRBt Scan Tool along with the DRB Low Cur-rent Shunt (LCS) adapter (Fig. 21) and its test leadswill be used to check fuel pump amperage specifica-tions.

(1) Be sure fuel tank contains fuel before startingtest. If tank is empty or near empty, amperage read-ings will be incorrect.

(2) Obtain LCS adapter.(3) Plug cable from LCS adapter into DRB scan

tool at SET 1 receptacle.(4) Plug DRB into vehicle 16–way connector (data

link connector).(5) Connect (-) and (+) test cable leads into LCS

adapter receptacles. Use 10 amp (10A +) receptacleand common (-) receptacles.

(6) Gain access to MAIN MENU on DRB screen.(7) Press DVOM button on DRB.(8) Using left/right arrow keys, highlight CHAN-

NEL 1 function on DRB screen.(9) Press ENTER three times.(10) Using up/down arrow keys, highlight RANGE

on DRB screen (screen will default to 2 amp scale).(11) Press ENTER to change 2 amp scale to 10

amp scale. This step must be done to preventdamage to DRB scan tool or LCS adapter(blown fuse).

(12) Remove cover from Power Distribution Center(PDC).

(13) Remove fuel pump relay from PDC. Refer tolabel on PDC cover for relay location.

Fig. 20 FUEL PRESSURE TEST GAUGE (TYPICALGAUGE INSTALLATION AT TEST PORT)

1 - SERVICE (TEST) PORT2 - FUEL PRESSURE TEST GAUGE3 - FUEL RAIL

Fig. 21 LOW CURRENT SHUNT1 - LOW CURRENT SHUNT ADAPTER2 - PLUG TO DRB3 - TEST LEAD RECEPTACLES


FUEL PUMP (Continued)

WARNING: BEFORE PROCEEDING TO NEXT STEP,NOTE THE FUEL PUMP WILL BE ACTIVATED ANDSYSTEM PRESSURE WILL BE PRESENT. THIS WILLOCCUR AFTER CONNECTING TEST LEADS FROMLCS ADAPTER INTO FUEL PUMP RELAY CAVITIES.THE FUEL PUMP WILL OPERATE EVEN WITH IGNI-TION KEY IN OFF POSITION. BEFORE ATTACHINGTEST LEADS, BE SURE ALL FUEL LINES ANDFUEL SYSTEM COMPONENTS ARE CONNECTED.

CAUTION: To prevent possible damage to the vehi-cle electrical system and LCS adapter, the testleads must be connected into relay cavities exactlyas shown in following steps.

Depending upon vehicle model, year or engine con-figuration, three different types of relays may beused: Type-1, type-2 and type–3.

(14) If equipped with type–1 relay (Fig. 22),attach test leads from LCS adapter into PDC relaycavities number 30 and 87. For location of these cav-ities, refer to numbers stamped to bottom of relay(Fig. 22).

(15) If equipped with type–2 relay (Fig. 23),attach test leads from LCS adapter into PDC relaycavities number 30 and 87. For location of these cav-ities, refer to numbers stamped to bottom of relay(Fig. 23).

(16) If equipped with type–3 relay (Fig. 24),attach test leads from LCS adapter into PDC relaycavities number 3 and 5. For location of these cavi-ties, refer to numbers stamped to bottom of relay(Fig. 24).

Fig. 22 FUEL PUMP RELAY - TYPE 1

Fig. 23 FUEL PUMP RELAY - TYPE 2TERMINAL LEGEND

NUMBER IDENTIFICATION30 COMMON FEED85 COIL GROUND86 COIL BATTERY87 NORMALLY OPEN

87A NORMALLY CLOSED

Fig. 24 FUEL PUMP RELAY - TYPE 3TERMINAL LEGEND

NUMBER IDENTIFICATION

1 COIL BATTERY2 COIL GROUND3 COMMON FEED4 NORMALLY CLOSED5 NORMALLY OPEN



(17) When LCS adapter test leads are attachedinto relay cavities, fuel pump will be activated.Determine fuel pump amperage on DRB screen.Amperage should be below 10.0 amps. If amperage isbelow 10.0 amps, and specifications for the FuelPump Pressure, Fuel Pump Capacity and Fuel Pres-sure Leak Down tests were met, the fuel pump mod-ule is OK.

(18) If amperage is more than 10.0 amps, replacefuel pump module assembly. The electric fuel pumpis not serviced separately.

(19) Disconnect test leads from relay cavitiesimmediately after testing.

FUEL PUMP MODULE

DESCRIPTIONThe fuel pump module assembly is located in the

fuel tank (Fig. 1). The assembly is divided into 2–sec-tions, upper and lower. The lower section is locked tothe bottom of the fuel tank. The complete assemblycontains the following components:

• A fuel pressure regulator• A separate fuel pick-up, or inlet filter• An electric fuel pump• A lockring to retain upper section of pump mod-

ule to tank• A rollover valve• A vent fitting for ORVR system• A soft gasket between tank flange and module• A fuel gauge sending unit (fuel level sensor)• Two fuel line connections (supply and return)The fuel gauge sending unit may be serviced sepa-

rately. If the electrical fuel pump, primary inlet filteror fuel pressure regulator require service, the lowersection of the fuel pump module must be replaced.

OPERATIONRefer to Fuel Pump, Inlet Filter, Fuel Pressure

Regulator and Fuel Gauge Sending Unit.

REMOVALThe fuel pump module is divided into 2 sections,

upper and lower. To service the check (control) valve,replace only the upper section. To service the fuelgauge sending unit, remove the upper section. To ser-vice the electric fuel pump, fuel pressure regulator orprimary inlet filter, remove both sections and replacelower section.

Fuel tank removal will not be necessary forfuel pump module removal. Access is from rearcargo area.

(1) Four cargo holdown clamps are located insidethe vehicle on the floor of the rear cargo area.

Remove the 2 rearward mounted clamps by drillingout the clamp rivets.




(5) Thoroughly clean area around top of pumpmodule to prevent contaminants from entering fueltank or fuel lines.

WARNING: THE FUEL SYSTEM IS UNDER A CON-STANT PRESSURE EVEN WITH ENGINE OFF.BEFORE SERVICING THE FUEL PUMP MODULE,FUEL SYSTEM PRESSURE MUST BE RELEASED.

(6) Release fuel system pressure. Refer to FuelSystem Pressure Release procedure.

(7) Disconnect 2 fuel lines at fuel pump module(Fig. 26) by pressing on 2 buttons at sides of fitting.

(8) Disconnect electrical connector (Fig. 26) at topof fuel pump module by sliding red colored tab firstto unlock, and push grey colored tab down forremoval.

(9) Disconnect ORVR hose clamp and hose (Fig.26) at pump module fitting.

(10) Remove module lockring (Fig. 26) using abrass drift and hammer (counter-clockwise).

(11) Carefully lift upper section of pump module(Fig. 26) from fuel tank exposing connections (liftupper section from tank very slowly until rub-ber gasket can be retained. If not, gasket willfall into fuel tank.)

(a) Disconnect electrical connector (Fig. 27) atbottom of upper pump module section.

(b) Disconnect fuel pressure regulator (Fig. 27)at bottom of upper pump module section. Press on2 locking tabs.

(c) Disconnect fuel return line (Fig. 27) at bot-tom of upper pump module section. Press on 2locking tabs.

(d) Remove upper section of pump module (Fig.28) from fuel tank.(12) Using an approved gas holding tank, drain

fuel tank through pump module opening. If check(control) valve, or, only upper section of pumpmodule is being serviced, tank draining is notnecessary. If any other fuel pump module com-ponent is being serviced, the tank must be com-pletely drained to the bottom.

(13) To remove lower section of pump module fromfuel tank:

(a) Using finger pressure, push on plasticrelease tab (Fig. 29) while sliding lock tab upward.



(b) The sides of pump module are equipped withtension springs (Fig. 29). These springs hold mod-ule to bottom of fuel tank into 2 formed guides(Fig. 30). Release module assembly from these 2guides by sliding toward right side of fuel tank.

(c) Lift assembly from fuel tank.

INSTALLATION

CAUTION: Whenever fuel pump module is serviced,pump module gasket must be replaced.

(1) Position lower section of fuel pump moduleassembly into fuel tank.

(2) The bottom of fuel tank has 2 formed guides.Lock module assembly into these 2 guides by slidingtoward left side of fuel tank.

(3) Push down on plastic tab to lock module to fueltank guides.

(4) Connect fuel supply line to bottom of upperpump module section.

(5) Connect fuel pressure regulator to bottom ofupper pump module section.

(6) Connect electrical connector to bottom of upperpump module section.

(7) Position pump module into fuel tank. Notch onmodule must be facing rear of tank.

(8) Position lock ring to module. Tap lockringusing a brass drift and hammer (clockwise) untilrotated up to built-on stops.

(9) Attach (snap on) 2 fuel filter fuel lines to top offuel pump module.

(10) Connect hoses/lines to ORVR components.(11) Fill fuel tank with fuel.(12) Start engine and check for fuel leaks.(13) Apply silicone sealant to bottom of fuel pump

module metal access plate.(14) Install fuel pump module metal access plate

and 4 nuts. Tighten nuts to 3 N·m (26 in. lbs.)torque.

(15) Position carpet and install 2 new cargo clamprivets into each cargo holdown clamp.




FUEL PUMP MODULE (Continued)



Fig. 28 UPPER SECTION - FUEL PUMP MODULE1 - UPPER SECTION - FUEL PUMP MODULE2 - FUEL TANK CHECK (CONTROL) VALVE

Fig. 29 LOWER SECTION - FUEL PUMP MODULE1 - LOWER SECTION - FUEL PUMP MODULE2 - RELEASE LOCK AND TAB3 - TENSION SPRINGS

Fig. 30 FUEL PUMP MODULE GUIDES (IN FUELTANK)

1 - FUEL TANK (INSIDE/LOWER)2 - FUEL PUMP MODULE GUIDES


FUEL PUMP MODULE (Continued)

FUEL RAIL

DESCRIPTION

2.4LThe fuel injector rail is used to mount the fuel

injectors to the engine (Fig. 31). On the 2.4L 4-cylin-der engine, a fuel damper is located near the frontof the fuel rail (Fig. 31).

3.7LThe fuel injector rail is mounted to the intake

manifold (Fig. 32). It is used to mount the fuel injec-tors to the engine. The rail is equipped with a testport (Fig. 33) to check/test fuel system pressure.

A fuel rail mounted, fuel damper is not used withthis engine.

OPERATION

2.4LThe fuel injector rail supplies the necessary fuel to

each individual fuel injector.

The fuel damper is used only to help control fuelpressure pulsations. These pulsations are the result

Fig. 31 FUEL RAIL-2.4L1 - FUEL RAIL2 - MOUNTING BOLTS3 - TEST PORT4 - QUICK-CONNECT FITTING5 - INJ. #16 - DAMPER7 - INJ #28 - INJ #39 - INJ #410- INJECTOR RETAINING CLIP

Fig. 32 FUEL RAIL - 3.7L1 - MOUNTING BOLTS (4)2 - QUICK-CONNECT FITTING3 - FUEL RAIL4 - INJ. #15 - INJ. #36 - INJ. #57 - INJ. #28 - INJ. #49 - INJ. #610 - CONNECTOR TUBE

Fig. 33 FUEL RAIL TEST PORT - 3.7L1 - FUEL RAIL2 - TEST PORT


of the firing of the fuel injectors. It is not used as afuel pressure regulator. The fuel pressure regulator isnot mounted to the fuel rail on any engine. It islocated on the fuel tank mounted fuel pump module.Refer to Fuel Pressure Regulator for additional infor-mation.

The fuel rail is not repairable.A quick-connect fitting with a safety latch is used

to attach the fuel line to the fuel rail.

3.7LHigh pressure fuel from the fuel pump is routed to

the fuel rail. The fuel rail then supplies the neces-sary fuel to each individual fuel injector.

A quick-connect fitting with a safety latch is usedto attach the fuel line to the fuel rail.

The fuel rail is not repairable.

REMOVAL

2.4L

WARNING: THE FUEL SYSTEM IS UNDER CON-STANT PRESSURE EVEN WITH ENGINE OFF.BEFORE SERVICING FUEL RAIL, FUEL SYSTEMPRESSURE MUST BE RELEASED.

The fuel rail can be removed without removing theintake manifold if the following procedures are fol-lowed.

(1) Remove fuel tank filler tube cap.(2) Perform Fuel System Pressure Release Proce-

dure.(3) Remove negative battery cable at battery.(4) Remove air duct at throttle body.(5) Disconnect fuel line latch clip and fuel line at

fuel rail. A special tool will be necessary for fuel linedisconnection. Refer to Quick-Connect Fittings.

(6) Remove necessary vacuum lines at throttlebody.

(7) Drain engine coolant and remove thermostatand thermostat housing.

(8) Remove PCV hose and valve at valve cover.(9) Remove 3 upper intake manifold mounting

bolts (Fig. 35), but only loosen 2 lower bolts about 2turns.

(10) Disconnect 2 main engine harness connectorsat rear of intake manifold (Fig. 34).

(11) Disconnect 2 injection wiring harness clips atharness mounting bracket (Fig. 35).

(12) Disconnect electrical connectors at all 4 fuelinjectors. To remove connector refer to (Fig. 37). Pushred colored slider away from injector (1). While push-ing slider, depress tab (2) and remove connector (3)from injector. The factory fuel injection wiring har-ness is numerically tagged (INJ 1, INJ 2, etc.) forinjector position identification. If harness is nottagged, note wiring location before removal.

(13) Remove 2 injection rail mounting bolts (Fig.31).

Fig. 34 MAP SENSOR LOCATION-2.4L1 - REAR OF INTAKE MANIFOLD2 - MAP SENSOR3 - ALIGNMENT PIN4 - MOUNTING BOLT (TORX)5 - ELECTRICAL CONNECTOR6 - MAIN ENGINE HARNESS CONNECTORS

Fig. 35 FUEL RAIL MOUNTING-2.4L1 - FUEL RAIL2 - INJECTION HARNESS CLIPS3 - LOWER MOUNTING HOLES4 - UPPER MOUNTING HOLES5 - INTAKE MANIFOLD


FUEL RAIL (Continued)

(14) Gently rock and pull fuel rail until fuel injec-tors just start to clear machined holes in intake man-ifold.

(15) Remove fuel rail (with injectors attached)from intake manifold.

(16) If fuel injectors are to be removed, refer toFuel Injector Removal/Installation.

3.7L

WARNING: THE FUEL SYSTEM IS UNDER CON-STANT PRESSURE EVEN WITH ENGINE OFF.BEFORE SERVICING FUEL RAIL, FUEL SYSTEMPRESSURE MUST BE RELEASED.

CAUTION: The left and right fuel rails are replacedas an assembly. Do not attempt to separate railhalves at connector tube (Fig. 36). Due to design oftube, it does not use any clamps. Never attempt toinstall a clamping device of any kind to tube. Whenremoving fuel rail assembly for any reason, be care-ful not to bend or kink tube.

(1) Remove fuel tank filler tube cap.(2) Perform Fuel System Pressure Release Proce-

dure.(3) Remove negative battery cable at battery.(4) Remove air duct at throttle body air box.(5) Remove air box at throttle body.(6) Disconnect fuel line latch clip and fuel line at

fuel rail. A special tool will be necessary for fuel linedisconnection. Refer to Quick-Connect Fittings.

(7) Remove necessary vacuum lines at throttlebody.

(8) Disconnect electrical connectors at all 6 fuelinjectors. To remove connector refer to (Fig. 37). Pushred colored slider away from injector (1). While push-ing slider, depress tab (2) and remove connector (3)from injector. The factory fuel injection wiring har-ness is numerically tagged (INJ 1, INJ 2, etc.) forinjector position identification. If harness is nottagged, note wiring location before removal.

(9) Disconnect electrical connectors at throttlebody sensors.

(10) Remove 6 ignition coils. Refer to Ignition CoilRemoval/Installation.

(11) Remove 4 fuel rail mounting bolts (Fig. 36).(12) Gently rock and pull left side of fuel rail until

fuel injectors just start to clear machined holes incylinder head. Gently rock and pull right side of railuntil injectors just start to clear cylinder head holes.Repeat this procedure (left/right) until all injectorshave cleared cylinder head holes.

(13) Remove fuel rail (with injectors attached)from engine.

Fig. 36 FUEL RAIL REMOVE/INSTALL - 3.7L1 - MOUNTING BOLTS (4)2 - QUICK-CONNECT FITTING3 - FUEL RAIL4 - INJ. #15 - INJ. #36 - INJ. #57 - INJ. #28 - INJ. #49 - INJ. #610 - CONNECTOR TUBE

Fig. 37 REMOVE/INSTALL INJECTOR CONNECTOR



(14) If fuel injectors are to be removed, refer toFuel Injector Removal/Installation.

INSTALLATION

2.4L Engine(1) If fuel injectors are to be installed, refer to Fuel

Injector Removal/Installation.(2) Clean out fuel injector machined bores in

intake manifold.(3) Apply a small amount of engine oil to each fuel

injector o-ring. This will help in fuel rail installation.(4) Position fuel rail/fuel injector assembly to

machined injector openings in intake manifold.(5) Guide each injector into cylinder head. Be care-

ful not to tear injector o-rings.(6) Push fuel rail down until fuel injectors have

bottomed on shoulders.(7) Install 2 fuel rail mounting bolts and tighten.

Refer to torque specifications.(8) Connect electrical connectors at all fuel injec-

tors. To install connector, refer to (Fig. 37). Push con-nector onto injector (1) and then push and lock redcolored slider (2). Verify connector is locked to injec-tor by lightly tugging on connector.

(9) Snap 2 injection wiring harness clips (Fig. 35)into brackets.

(10) Connect 2 main engine harness connectors atrear of intake manifold (Fig. 34).

(11) Tighten 5 intake manifold mounting bolts.Refer to Engine Torque Specifications.

(12) Install PCV valve and hose.(13) Install thermostat and radiator hose. Fill with

coolant. Refer to Cooling.(14) Connect necessary vacuum lines to throttle

body.(15) Connect fuel line latch clip and fuel line to

fuel rail. Refer to Quick-Connect Fittings.(16) Install air duct to throttle body.(17) Connect battery cable to battery.(18) Start engine and check for leaks.

3.7L Engine(1) If fuel injectors are to be installed, refer to Fuel

Injector Removal/Installation.(2) Clean out fuel injector machined bores in

intake manifold.(3) Apply a small amount of engine oil to each fuel

injector o-ring. This will help in fuel rail installation.(4) Position fuel rail/fuel injector assembly to

machined injector openings in cylinder head.(5) Guide each injector into cylinder head. Be care-

ful not to tear injector o-rings.(6) Push right side of fuel rail down until fuel

injectors have bottomed on cylinder head shoulder.

Push left fuel rail down until injectors have bot-tomed on cylinder head shoulder.

(7) Install 4 fuel rail mounting bolts and tighten.Refer to torque specifications.

(8) Install 6 ignition coils. Refer to Ignition CoilRemoval/Installation.

(9) Connect electrical connectors to throttle body.(10) Connect electrical connectors at all fuel injec-

tors. To install connector, refer to (Fig. 37). Push con-nector onto injector (1) and then push and lock redcolored slider (2). Verify connector is locked to injec-tor by lightly tugging on connector.

(11) Connect necessary vacuum lines to throttlebody.

(12) Connect fuel line latch clip and fuel line tofuel rail. Refer to Quick-Connect Fittings.

(13) Install air box to throttle body.(14) Install air duct to air box.(15) Connect battery cable to battery.(16) Start engine and check for leaks.

FUEL TANK

DESCRIPTIONThe fuel tank is constructed of a plastic material.

Its main functions are for fuel storage and for place-ment of the fuel pump module, and certain ORVRcomponents.

OPERATIONAll models pass a full 360 degree rollover test

without fuel leakage. To accomplish this, fuel andvapor flow controls are required for all fuel tank con-nections.

A check (control) valve is mounted into the top sec-tion of the 2–piece fuel pump module. Refer to FuelTank Check Valve for additional information.

An evaporation control system is connected to thefuel tank to reduce emissions of fuel vapors into theatmosphere. When fuel evaporates from the fueltank, vapors pass through vent hoses or tubes to acharcoal canister where they are temporarily held.When the engine is running, the vapors are drawninto the intake manifold. Certain models are alsoequipped with a self-diagnosing system using a LeakDetection Pump (LDP) and/or an ORVR system.Refer to Emission Control System for additionalinformation.



REMOVAL

Fuel Tank Draining

WARNING: THE FUEL SYSTEM MAY BE UNDERCONSTANT FUEL PRESSURE EVEN WITH THEENGINE OFF. THIS PRESSURE MUST BERELEASED BEFORE SERVICING FUEL TANK.

Two different procedures may be used to drain fueltank: removing fuel pump module access plate, orusing DRBt scan tool. Due to a one-way check valveinstalled into the fuel fill opening fitting at the tank(Fig. 38), the tank cannot be drained conventionallyat the fill cap.

The quickest draining procedure involves removingfuel pump module access plate.

As an alternative procedure, the electric fuel pumpmay be activated allowing tank to be drained at fuelrail connection. Refer to DRB scan tool for fuel pumpactivation procedures. Before disconnecting fuel lineat fuel rail, release fuel pressure. Refer to the FuelSystem Pressure Release Procedure for procedures.Attach end of special test hose tool number 6541,6539, 6631 or 6923 at fuel rail disconnection (toolnumber will depend on model and/or engine applica-tion). Position opposite end of this hose tool to anapproved gasoline draining station. Activate fuelpump and drain tank until empty.

If electric fuel pump is not operating, fuel pumpmodule access plate must be removed for fuel drain-ing. Refer to following procedures.

Fuel tank removal will not be necessary forfuel tank draining. Access for draining is fromrear cargo area.

(1) Open all windows in vehicle to allow for airventilation.

(2) Four cargo holdown clamps are located insidethe vehicle on the floor of the rear cargo area.Remove the 2 rearward mounted clamps by drillingout the clamp rivets.




(6) Thoroughly clean area around top of pumpmodule to prevent contaminants from entering fueltank or fuel lines.

(7) Release fuel system pressure.(8) Disconnect 2 fuel lines (Fig. 40) at fuel pump

module by pressing on tabs at side of fitting.(9) Disconnect electrical connector (Fig. 40). Slide

red tab first to unlock, and push grey tab down forremoval.

(10) Disconnect ORVR hose (Fig. 40) at pump mod-ule fitting.

Fig. 38 FUEL FILL CHECK VALVE1 - ONE-WAY CHECK VALVE2 - FUEL FILL FITTING3 - SIDE OF FUEL TANK



FUEL TANK (Continued)

(11) Remove module lockring (Fig. 40) using abrass drift and hammer (counter-clockwise).

(12) Carefully lift upper section of pump modulefrom fuel tank a few inches (lift upper sectionfrom tank very slowly until rubber gasket canbe retained. If not, gasket will fall into fueltank).

(13) Using an approved gas holding tank, drainfuel tank through fuel pump module opening.

Tank Removal(1) After draining tank, temporarily place upper

section of fuel pump module back into fuel tank.(2) Raise vehicle.(3) If equipped, remove fuel tank skid plate and

tow hooks. Certain equipment packages will alsorequire removal of the trailer hitch. Refer to TowHooks, Trailer Hitch or Skid Plate in 23, Body forremoval/installation procedures.

(4) Disconnect fuel filter ground strap.(5) Disconnect fuel filter outlet line from body

retention clip located on frame near front/center oftank (Fig. 41). Place a small screwdriver into side ofclip and twist for removal. Also disconnect LeakDetection Pump (LDP) line (Fig. 41) from this clip.

(6) Remove both 3/4” hoses at sides of Leak Detec-tion Pump (LDP) (Fig. 41).

(7) Disconnect 3/4” flow management valve hose(Fig. 41) at EVAP canister.

(8) Remove fuel fill hose clamp (Fig. 42) at fueltank, and disconnect hose from fuel tank.

(9) A third fuel line is attached to bottom of fuelfilter. The disconnection point (quick-connect fitting)for this 3rd line is approximately 1 foot from front oftank towards front of vehicle (Fig. 41). Clean connec-tion point before disconnection. Disconnect by press-ing on tabs at side of quick-connect fitting. Alsodisconnect LDP vent line near this same point.

(10) Disconnect 2 vacuum/vent hoses from plasticretention clip at left/front of fuel tank line (Fig. 41).

(11) Support tank with a hydraulic jack.(12) Remove 4 fuel tank strap bolts (Fig. 41) (2 at

front of tank; 2 at rear of tank), and remove bothtank support straps (Fig. 41).

(13) Carefully lower tank a few inches and discon-nect electrical connector at top of LDP (Fig. 43). Todisconnect electrical connector: Push upward on redcolored tab to unlock. Push on black colored tabwhile removing connector.


Fig. 41 FRONT OF FUEL TANK1 - TANK MOUNTING BOLTS (4)2 - TANK MOUNTING STRAPS (2)3 - LEAK DETECTION PUMP (LDP)4 - BODY RETENTION CLIP (CENTER)5 - LDP HOSES6 - HOSE TO FUEL MANAGEMENT VALVE7 - BODY RETENTION CLIP (LEFT/FRONT)8 - QUICK-CONECT FITTING9 - LDP LINE



(14) Continue lowering tank while guiding remain-ing hoses and lines.

(15) If fuel tank is to be replaced, remove LDP,fuel filter and fuel pump module from tank. Refer toLeak Detection Pump, Fuel Filter and Fuel PumpModule Removal/Installation procedures.

INSTALLATION(1) If fuel tank is to be replaced, install LDP, fuel

filter and fuel pump module to tank. Refer to LeakDetection Pump, Fuel Filter and Fuel Pump ModuleRemoval/Installation procedures.

(2) Position fuel tank to hydraulic jack.(3) Raise tank while carefully guiding vent tubes/

hoses through frame rail and crossmember. Beforetank reaches body, connect electrical connector toLeak Detection Pump (LDP).

(4) Continue raising tank until positioned to body.(5) Attach two fuel tank mounting straps and 4

mounting bolts. Tighten bolts to 61 N·m (45 ft. lbs.)torque.

(6) Connect 2 hoses to body retention clip at left/front of tank.

(7) Connect fuel filter fuel line to main fuel line(snaps together). After connecting, snap this line intobody retention clip. Also connect LDP vacuum hosenear this point.

(8) Install fuel fill hose and hose clamp to fueltank fitting. Rotate hose until white painted indexmark on hose (Fig. 42) is located between alignmentnotches on fuel tank fitting. Tighten clamp to 3.4N·m (30 in. lbs.) torque.

(9) Connect fresh air and recirculation lines to fuelfill tube.

(10) Connect 3/4” lines to Leak Detection Pump(LDP).

(11) Connect 3/4” flow management valve hose toEVAP canister.

(12) Snap remaining lines into body retention clipat front/center of fuel tank.

(13) If equipped, install fuel tank skid plate,trailer hitch and tow hooks. Refer to Tow Hooks,Trailer Hitch or Skid Plate in 23, Body for removal/installation procedures.

(14) Lower vehicle.(15) Attach (snap on) 2 fuel filter fuel lines to top

of fuel pump module.(16) Install electrical connector to top of fuel pump

module.(17) Connect negative battery cable to battery.(18) Fill fuel tank with fuel.(19) Start engine and check for fuel leaks near top

of module.(20) Apply silicone sealant to bottom of fuel pump

module metal access plate.

Fig. 42 FUEL FILL HOSE AT TANK1 - FUEL FILL HOSE AT TANK2 - HOSE CLAMP3 - WHITE PAINTED INDEX MARK4 - ALIGNMENT NOTCHES5 - LEFT SIDE OF FUEL TANK6 - FUEL FILL FITTING

Fig. 43 LDP ELECTRICAL CONNECTOR1 - LEAK DETECTION PUMP (LDP)2 - ELECTRICAL CONNECTOR3 - FUEL FILTER



(21) Install fuel pump module metal access plateand 4 nuts. Tighten nuts to 3 N·m (26 in. lbs.)torque.

(22) Position carpet and install 2 new cargo clamprivets into each cargo holdown clamp.

FUEL TANK CHECK VALVE

DESCRIPTIONThe fuel tank is equipped with a check valve. The

valve (also referred to as a control valve) is located inthe top section of the fuel pump module assembly(Fig. 1).

OPERATIONThe fuel tank check valve (also referred to as

either a control valve, one-way check valve or floatvalve) will prevent fuel flow through the fuel tankvent in the event of an accidental vehicle rollover. Itis also used as a part of the ORVR system. TheEVAP canister and ORVR system draw fuel vaporsfrom the fuel tank through this valve. Refer to ORVRin Emissions for additional information.

The valve may be serviced by replacing the uppersection of the fuel pump module assembly.

REMOVALThe fuel tank check (control) valve is attached into

the top section of the fuel pump module (Fig. 44). Ifreplacement is necessary, the top section of the fuelpump module must be replaced. Refer to Fuel PumpModule Removal/Installation.

INSTALLATIONThe fuel tank check (control) valve is attached to

the top section of the fuel pump module. If replace-ment is necessary, the top section of the fuel pumpmodule must be replaced. Refer to Fuel Pump Mod-ule Removal/Installation.

INLET FILTER

REMOVALThe fuel pump inlet filter is located on the bottom/

side of the lower fuel pump module section (Fig. 45).The fuel pump module assembly is located in the fueltank.

(1) Remove lower section of fuel pump module.Refer to Fuel Pump Module Removal/Installation.

(2) Remove filter by prying from pump modulewith 2 small screwdrivers. Filter is snapped to mod-ule with 2 release tabs (Fig. 45).

(3) Clean filter entrance into pump module open-ing.

INSTALLATION(1) Snap new filter to bottom of fuel pump module.(2) Install lower section of fuel pump module.

Refer to Fuel Pump Module Removal/Installation.

Fig. 44 UPPER SECTION - FUEL PUMP MODULE1 - UPPER SECTION - FUEL PUMP MODULE2 - FUEL TANK CHECK (CONTROL) VALVE

Fig. 45 INLET FILTER1 - INLET FILTER2 - RELEASE TABS (2)3 - BOTTOM OF FUEL PUMP MODULE



FUEL INJECTION

TABLE OF CONTENTS

page page

FUEL INJECTIONDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 29

ACCELERATOR PEDALREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 30

CRANKSHAFT POSITION SENSORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 30OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 31REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 32

FUEL INJECTORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 33OPERATION

OPERATION - FUEL INJECTOR . . . . . . . . . . 33OPERATION - PCM OUTPUT . . . . . . . . . . . . 33

DIAGNOSIS AND TESTING - FUEL INJECTOR . 33REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 34

FUEL PUMP RELAYDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 34OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 34DIAGNOSIS AND TESTING - FUEL PUMP

RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 34

IDLE AIR CONTROL MOTORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 35OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 35REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 36INTAKE AIR TEMPERATURE SENSOR

DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 36OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 36REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 38

MAP SENSORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 38OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 38REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 40

OXYGEN SENSORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 40OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 40REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 43

THROTTLE BODYDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 43OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 43REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 44

THROTTLE CONTROL CABLEREMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 46

THROTTLE POSITION SENSORDESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . 47OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 47REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . 48

FUEL INJECTION

DESCRIPTIONThe Powertrain Control Module (PCM) operates

the fuel injection system. Refer to Powertrain ControlModule in Electronic Control Modules for informa-tion.

ACCELERATOR PEDAL

REMOVALThe accelerator pedal is serviced as a complete

assembly including the bracket.

The accelerator pedal is connected to the upperpart of the accelerator pedal arm by a plasticretainer (clip) (Fig. 1). This plastic retainer snapsinto the top of the accelerator pedal arm.

(1) From inside the vehicle, hold up acceleratorpedal. Remove plastic cable retainer (clip) and throt-tle cable core wire from upper end of acceleratorpedal arm (Fig. 1). Plastic cable retainer (clip) snapsinto pedal arm.

(2) Remove 2 accelerator pedal mounting bracketnuts. Remove accelerator pedal assembly.

KJ FUEL INJECTION 14 - 29

INSTALLATION(1) Place accelerator pedal assembly over 2 studs

(Fig. 1) protruding from floor pan.(2) Install 2 mounting nuts. Refer to torque speci-

fications.(3) Slide throttle cable into opening slot in top of

pedal arm.(4) Push plastic cable retainer (clip) into accelera-

tor pedal arm opening until it snaps into place.(5) Before starting engine, operate accelerator

pedal to check for any binding.

CRANKSHAFT POSITIONSENSOR

DESCRIPTION

2.4LThe Crankshaft Position (CKP) sensor is mounted

into the right front side of the cylinder block (Fig. 2).It is positioned and bolted into a machined hole.


into the right rear side of the cylinder block (Fig. 3).It is positioned and bolted into a machined hole.

Fig. 1 ACCELERATOR PEDAL/BRACKET ASSEMBLY1 - METAL THROTTLE CABLE CLIP2 - THROTTLE CABLE3 - PLASTIC CABLE RETAINER4 - PEDAL/BRACKET ASSEMBLY5 - PEDAL MOUNTING NUTS (2)6 - PEDAL MOUNTING STUDS (2)

Fig. 2 CKP SENSOR LOCATION-2.4L1 - RIGHT FRONT ENGINE MOUNT2 - CKP SENSOR3 - MOUNTING BOLT4 - ELECTRICAL CONNECTOR

Fig. 3 CKP - 3.7L1 - MOUNTING BOLT2 - CKP SENSOR3 - O-RING

14 - 30 FUEL INJECTION KJ

ACCELERATOR PEDAL (Continued)

OPERATION

2.4LEngine speed and crankshaft position are provided

through the CKP (Crankshaft Position) sensor. Thesensor generates pulses that are the input sent to thePowertrain Control Module (PCM). The PCM inter-prets the sensor input to determine the crankshaftposition. The PCM then uses this position, along withother inputs, to determine injector sequence and igni-tion timing.

The sensor is a hall effect device combined with aninternal magnet. It is also sensitive to steel within acertain distance from it.

A tonewheel (targetwheel) is a part of the enginecrankshaft (Fig. 4). This tonewheel has sets ofnotches at its outer edge.

The notches cause a pulse to be generated whenthey pass under the sensor. The pulses are the inputto the PCM.

3.7LEngine speed and crankshaft position are provided

through the CKP (Crankshaft Position) sensor. Thesensor generates pulses that are the input sent to thePowertrain Control Module (PCM). The PCM inter-prets the sensor input to determine the crankshaftposition. The PCM then uses this position, along withother inputs, to determine injector sequence and igni-tion timing.

The sensor is a hall effect device combined with aninternal magnet. It is also sensitive to steel within acertain distance from it.

A tonewheel (targetwheel) is bolted to the enginecrankshaft (Fig. 5). This tonewheel has sets ofnotches at its outer edge (Fig. 5).

The notches cause a pulse to be generated whenthey pass under the sensor. The pulses are the inputto the PCM.

REMOVAL


into the right front side of the cylinder block (Fig. 6).It is positioned and bolted into a machined hole.

(1) Disconnect sensor electrical connector.(2) Remove sensor bolt.(3) Carefully pry sensor from cylinder block in a

rocking action.(4) Check condition of sensor o-ring (Fig. 7).


into the right rear side of the cylinder block (Fig. 8).It is positioned and bolted into a machined hole.

(1) Raise vehicle.(2) Disconnect sensor electrical connector.(3) Remove sensor mounting bolt (Fig. 8).(4) Carefully remove sensor from cylinder block in

a rocking and twisting action.(5) Check condition of sensor o-ring.

Fig. 4 CKP OPERATION-2.4L1 - NOTCHES2 - CRANKSHAFT

Fig. 5 CKP OPERATION-3.7L1 - TONEWHEEL2 - NOTCHES3 - CRANKSHAFT POSITION SENSOR4 - CRANKSHAFT


CRANKSHAFT POSITION SENSOR (Continued)

INSTALLATION

2.4L(1) Clean out machined hole in engine block.(2) Apply a small amount of engine oil to sensor

o-ring.

(3) Install sensor into engine block with a slightrocking action. Do not twist sensor into position asdamage to o-ring may result.

CAUTION: Before tightening sensor mounting bolt,be sure sensor is completely flush to cylinderblock. If sensor is not flush, damage to sensormounting tang may result.

(4) Install mounting bolt and tighten to 28 N·m(21 ft. lbs.) torque.

(5) Connect electrical connector to sensor.

3.7L(1) Clean out machined hole in engine block.(2) Apply a small amount of engine oil to sensor

o-ring.(3) Install sensor into engine block with a slight

rocking and twisting action.

CAUTION: Before tightening sensor mounting bolt,be sure sensor is completely flush to cylinderblock. If sensor is not flush, damage to sensormounting tang may result.

(4) Install mounting bolt and tighten to 28 N·m(21 ft. lbs.) torque.

(5) Connect electrical connector to sensor.(6) Lower vehicle.

Fig. 6 CKP SENSOR LOCATION-2.4L1 - RIGHT FRONT ENGINE MOUNT2 - CKP SENSOR3 - MOUNTING BOLT4 - ELECTRICAL CONNECTOR

Fig. 7 CKP AND O-RING-2.4L1 - CKP SENSOR2 - O-RING

Fig. 8 CKP - 3.7L1 - MOUNTING BOLT2 - CKP SENSOR3 - O-RING


CRANKSHAFT POSITION SENSOR (Continued)

FUEL INJECTOR

DESCRIPTIONAn individual fuel injector (Fig. 9) is used for each

individual cylinder.

OPERATION

OPERATION - FUEL INJECTORThe top (fuel entry) end of the injector (Fig. 9) is

attached into an opening on the fuel rail.The fuel injectors are electrical solenoids. The

injector contains a pintle that closes off an orifice atthe nozzle end. When electric current is supplied tothe injector, the armature and needle move a shortdistance against a spring, allowing fuel to flow outthe orifice. Because the fuel is under high pressure, afine spray is developed in the shape of a pencilstream. The spraying action atomizes the fuel, add-ing it to the air entering the combustion chamber.

The nozzle (outlet) ends of the injectors are posi-tioned into openings in the intake manifold justabove the intake valve ports of the cylinder head.The engine wiring harness connector for each fuelinjector is equipped with an attached numerical tag(INJ 1, INJ 2 etc.). This is used to identify each fuelinjector.

The injectors are energized individually in asequential order by the Powertrain Control Module

(PCM). The PCM will adjust injector pulse width byswitching the ground path to each individual injectoron and off. Injector pulse width is the period of timethat the injector is energized. The PCM will adjustinjector pulse width based on various inputs itreceives.

Battery voltage is supplied to the injectors throughthe ASD relay.

The PCM determines injector pulse width based onvarious inputs.

OPERATION - PCM OUTPUTThe nozzle ends of the injectors are positioned into

openings in the intake manifold just above the intakevalve ports of the cylinder head. The engine wiringharness connector for each fuel injector is equippedwith an attached numerical tag (INJ 1, INJ 2 etc.).This is used to identify each fuel injector with itsrespective cylinder number.

The injectors are energized individually in asequential order by the Powertrain Control Module(PCM). The PCM will adjust injector pulse width byswitching the ground path to each individual injectoron and off. Injector pulse width is the period of timethat the injector is energized. The PCM will adjustinjector pulse width based on various inputs itreceives.

Battery voltage (12 volts +) is supplied to the injec-tors through the ASD relay. The ASD relay will shut-down the 12 volt power source to the fuel injectors ifthe PCM senses the ignition is on, but the engine isnot running. This occurs after the engine has notbeen running for approximately 1.8 seconds.

The PCM determines injector on-time (pulse width)based on various inputs.

DIAGNOSIS AND TESTING - FUEL INJECTORTo perform a complete test of the fuel injectors and

their circuitry, use the DRB scan tool and refer to theappropriate Powertrain Diagnostics Procedures man-ual. To test the injector only, refer to the following:

Disconnect the fuel injector wire harness connectorfrom the injector. The injector is equipped with 2electrical terminals (pins). Place an ohmmeter acrossthe terminals. Resistance reading should be approxi-mately 12 ohms ±1.2 ohms at 20°C (68°F).

Fig. 9 FUEL INJECTOR — TYPICAL


REMOVAL(1) Remove fuel rail. Refer to Fuel Injector Rail

Removal.(2) Disconnect clip(s) that retain fuel injector(s) to

fuel rail (Fig. 10).

INSTALLATION(1) Install fuel injector(s) into fuel rail assembly

and install retaining clip(s).(2) If same injector(s) is being reinstalled, install

new o-ring(s).(3) Apply a small amount of clean engine oil to

each injector o-ring. This will aid in installation.(4) Install fuel rail. Refer to Fuel Rail Installation.(5) Start engine and check for fuel leaks.

FUEL PUMP RELAY

DESCRIPTIONThe 5–pin, 12–volt, fuel pump relay is located in

the Power Distribution Center (PDC). Refer to thelabel on the PDC cover for relay location.

OPERATIONThe Powertrain Control Module (PCM) energizes

the electric fuel pump through the fuel pump relay.The fuel pump relay is energized by first applyingbattery voltage to it when the ignition key is turned

ON, and then applying a ground signal to the relayfrom the PCM.

Whenever the ignition key is turned ON, the elec-tric fuel pump will operate. But, the PCM will shut-down the ground circuit to the fuel pump relay inapproximately 1–3 seconds unless the engine is oper-ating or the starter motor is engaged.

DIAGNOSIS AND TESTING - FUEL PUMPRELAY

For procedures, refer to ASD Relay Diagnosis andTesting in the Ignition section.

REMOVALThe fuel pump relay is located in the Power Distri-

bution Center (PDC) (Fig. 11). Refer to label on PDCcover for relay location.

(1) Remove PDC cover.(2) Remove relay from PDC.(3) Check condition of relay terminals and PDC

connector terminals for damage or corrosion. Repairif necessary before installing relay.

(4) Check for pin height (pin height should be thesame for all terminals within the PDC connector).Repair if necessary before installing relay.

INSTALLATIONThe fuel pump relay is located in the Power Distri-

bution Center (PDC). Refer to label on PDC cover forrelay location.

(1) Install relay to PDC.(2) Install cover to PDC.

Fig. 10 INJECTOR RETAINING CLIP1 - PLIERS2 - INJECTOR CLIP3 - FUEL INJECTOR4 - FUEL RAIL - TYPICAL

Fig. 11 POWER DISTRIBUTION CENTER (PDC)1 - BATTERY2 - PDC3 - PDC COVER


FUEL INJECTOR (Continued)

IDLE AIR CONTROL MOTOR

DESCRIPTIONThe IAC stepper motor is mounted to the throttle

body, and regulates the amount of air bypassing thecontrol of the throttle plate. As engine loads andambient temperatures change, engine rpm changes.A pintle on the IAC stepper motor protrudes into apassage in the throttle body, controlling air flowthrough the passage. The IAC is controlled by thePowertrain Control Module (PCM) to maintain thetarget engine idle speed.

OPERATIONAt idle, engine speed can be increased by retract-

ing the IAC motor pintle and allowing more air topass through the port, or it can be decreased byrestricting the passage with the pintle and diminish-ing the amount of air bypassing the throttle plate.

The IAC is called a stepper motor because it ismoved (rotated) in steps, or increments. Opening theIAC opens an air passage around the throttle bladewhich increases RPM.

The PCM uses the IAC motor to control idle speed(along with timing) and to reach a desired MAP dur-ing decel (keep engine from stalling).

The IAC motor has 4 wires with 4 circuits. Two ofthe wires are for 12 volts and ground to supply elec-trical current to the motor windings to operate thestepper motor in one direction. The other 2 wires arealso for 12 volts and ground to supply electrical cur-rent to operate the stepper motor in the oppositedirection.

To make the IAC go in the opposite direction, thePCM just reverses polarity on both windings. If only1 wire is open, the IAC can only be moved 1 step(increment) in either direction. To keep the IACmotor in position when no movement is needed, thePCM will energize both windings at the same time.This locks the IAC motor in place.

In the IAC motor system, the PCM will countevery step that the motor is moved. This allows thePCM to determine the motor pintle position. If thememory is cleared, the PCM no longer knows theposition of the pintle. So at the first key ON, thePCM drives the IAC motor closed, regardless ofwhere it was before. This zeros the counter. From

this point the PCM will back out the IAC motor andkeep track of its position again.

When engine rpm is above idle speed, the IAC isused for the following:

• Off-idle dashpot (throttle blade will close quicklybut idle speed will not stop quickly)

• Deceleration air flow control• A/C compressor load control (also opens the pas-

sage slightly before the compressor is engaged sothat the engine rpm does not dip down when thecompressor engages)

• Power steering load controlThe PCM can control polarity of the circuit to con-

trol direction of the stepper motor.IAC Stepper Motor Program: The PCM is also

equipped with a memory program that records thenumber of steps the IAC stepper motor most recentlyadvanced to during a certain set of parameters. Forexample: The PCM was attempting to maintain a1000 rpm target during a cold start-up cycle. The lastrecorded number of steps for that may have been125. That value would be recorded in the memorycell so that the next time the PCM recognizes theidentical conditions, the PCM recalls that 125 stepswere required to maintain the target. This programallows for greater customer satisfaction due togreater control of engine idle.

Another function of the memory program, whichoccurs when the power steering switch (if equipped),or the A/C request circuit, requires that the IAC step-per motor control engine rpm, is the recording of thelast targeted steps into the memory cell. The PCMcan anticipate A/C compressor loads. This is accom-plished by delaying compressor operation for approx-imately 0.5 seconds until the PCM moves the IACstepper motor to the recorded steps that were loadedinto the memory cell. Using this program helps elim-inate idle-quality changes as loads change. Finally,the PCM incorporates a 9No-Load9 engine speed lim-iter of approximately 1800 - 2000 rpm, when it rec-ognizes that the TPS is indicating an idle signal andIAC motor cannot maintain engine idle.

A (factory adjusted) set screw is used to mechani-cally limit the position of the throttle body throttleplate. Never attempt to adjust the engine idlespeed using this screw. All idle speed functions arecontrolled by the IAC motor through the PCM.


REMOVAL

2.4LThe Idle Air Control (IAC) motor is located on the

rear side of the throttle body (Fig. 12).(1) Disconnect electrical connector from IAC motor.(2) Remove two mounting bolts (screws).(3) Remove IAC motor from throttle body.


side of the throttle body (Fig. 13).(1) Disconnect electrical connector from IAC motor.(2) Remove two mounting bolts (screws).(3) Remove IAC motor from throttle body.

INSTALLATION


rear side of the throttle body.(1) Install IAC motor to throttle body.(2) Install and tighten two mounting bolts (screws)

to 7 N·m (60 in. lbs.) torque.(3) Install electrical connector.


side of the throttle body (Fig. 13).(1) Install IAC motor to throttle body.

(2) Install and tighten two mounting bolts (screws)to 7 N·m (60 in. lbs.) torque.

(3) Install electrical connector.

INTAKE AIR TEMPERATURESENSOR

DESCRIPTIONThe 2–wire Intake Manifold Air Temperature (IAT)

sensor is installed in the intake manifold with thesensor element extending into the air stream.

The IAT sensor is a two-wire Negative ThermalCoefficient (NTC) sensor. Meaning, as intake mani-fold temperature increases, resistance (voltage) in thesensor decreases. As temperature decreases, resis-tance (voltage) in the sensor increases.

OPERATIONThe IAT sensor provides an input voltage to the

Powertrain Control Module (PCM) indicating thedensity of the air entering the intake manifold basedupon intake manifold temperature. At key-on, a5–volt power circuit is supplied to the sensor fromthe PCM. The sensor is grounded at the PCMthrough a low-noise, sensor-return circuit.

The PCM uses this input to calculate the following:• Injector pulse-width• Adjustment of spark timing (to help prevent

spark knock with high intake manifold air-chargetemperatures)

Fig. 12 TPS/IAC MOTOR - 2.4L1 - THROTTLE POSITION SENSOR (TPS)2 - MOUNTING SCREWS3 - IDLE AIR CONTROL MOTOR (IAC)4 - MOUNTING SCREWS



IDLE AIR CONTROL MOTOR (Continued)

The resistance values of the IAT sensor is the sameas for the Engine Coolant Temperature (ECT) sensor.

REMOVAL

2.4LThe intake manifold air temperature (IAT) sensor

is installed into the intake manifold plenum at therear end of the intake manifold (Fig. 14).

(1) Disconnect electrical connector from IAT sen-sor.

(2) Clean dirt from intake manifold at sensor base.(3) Gently lift on small plastic release tab (Fig. 14)

or (Fig. 15) and rotate sensor about 1/4 turn counter-clockwise for removal.

(4) Check condition of sensor o-ring (Fig. 15).


is installed into the left side of intake manifold ple-num (Fig. 16).

(1) Disconnect electrical connector from IAT sen-sor.

(2) Clean dirt from intake manifold at sensor base.(3) Gently lift on small plastic release tab (Fig. 16)

or (Fig. 15) and rotate sensor about 1/4 turn counter-clockwise for removal.

(4) Check condition of sensor o-ring.

Fig. 14 IAT SENSOR LOCATION-2.4L1 - RELEASE TAB2 - IAT SENSOR3 - PRESS HERE FOR REMOVAL4 - ELECTRICAL CONNECTOR5 - REAR END OF INTAKE MANIFOLD

Fig. 15 IAT SENSOR TAB / O-RING1 - IAT SENSOR2 - SENSOR O-RING3 - RELEASE TAB

Fig. 16 IAT SENSOR LOCATION- 3.7L1 - IAT SENSOR2 - RELEASE TAB3 - ELECTRICAL CONNECTOR


INTAKE AIR TEMPERATURE SENSOR (Continued)

INSTALLATION


is installed into the intake manifold plenum at therear end of the intake manifold.

(1) Check condition of sensor o-ring.(2) Clean sensor mounting hole in intake manifold.(3) Position sensor into intake manifold and rotate

clockwise until past release tab.(4) Install electrical connector.


is installed into the left side of intake manifold ple-num (Fig. 16).

(1) Check condition of sensor o-ring.(2) Clean sensor mounting hole in intake manifold.(3) Position sensor into intake manifold and rotate

clockwise until past release tab (Fig. 16).(4) Install electrical connector.

MAP SENSOR

DESCRIPTION

2.4LThe Manifold Absolute Pressure (MAP) sensor is

mounted into the rear of the intake manifold with 1screw.


mounted into the front of the intake manifold with 2screws.

OPERATIONThe MAP sensor is used as an input to the Power-

train Control Module (PCM). It contains a siliconbased sensing unit to provide data on the manifoldvacuum that draws the air/fuel mixture into the com-bustion chamber. The PCM requires this informationto determine injector pulse width and spark advance.When manifold absolute pressure (MAP) equalsBarometric pressure, the pulse width will be at max-imum.

A 5 volt reference is supplied from the PCM andreturns a voltage signal to the PCM that reflectsmanifold pressure. The zero pressure reading is 0.5Vand full scale is 4.5V. For a pressure swing of 0–15psi, the voltage changes 4.0V. To operate the sensor,it is supplied a regulated 4.8 to 5.1 volts. Ground isprovided through the low-noise, sensor return circuitat the PCM.

The MAP sensor input is the number one contrib-utor to fuel injector pulse width. The most importantfunction of the MAP sensor is to determine baromet-ric pressure. The PCM needs to know if the vehicle isat sea level or at a higher altitude, because the airdensity changes with altitude. It will also help to cor-rect for varying barometric pressure. Barometricpressure and altitude have a direct inverse correla-tion; as altitude goes up, barometric goes down. Atkey-on, the PCM powers up and looks at MAP volt-age, and based upon the voltage it sees, it knows thecurrent barometric pressure (relative to altitude).Once the engine starts, the PCM looks at the voltageagain, continuously every 12 milliseconds, and com-pares the current voltage to what it was at key-on.The difference between current voltage and what itwas at key-on, is manifold vacuum.

During key-on (engine not running) the sensorreads (updates) barometric pressure. A normal rangecan be obtained by monitoring a known good sensor.

As the altitude increases, the air becomes thinner(less oxygen). If a vehicle is started and driven to avery different altitude than where it was at key-on,the barometric pressure needs to be updated. Anytime the PCM sees Wide Open Throttle (WOT), basedupon Throttle Position Sensor (TPS) angle and RPM,it will update barometric pressure in the MAP mem-ory cell. With periodic updates, the PCM can makeits calculations more effectively.

The PCM uses the MAP sensor input to aid in cal-culating the following:

• Manifold pressure• Barometric pressure• Engine load• Injector pulse-width• Spark-advance programs• Shift-point strategies (certain automatic trans-

missions only)• Idle speed• Decel fuel shutoffThe MAP sensor signal is provided from a single

piezoresistive element located in the center of a dia-phragm. The element and diaphragm are both madeof silicone. As manifold pressure changes, the dia-phragm moves causing the element to deflect, whichstresses the silicone. When silicone is exposed tostress, its resistance changes. As manifold vacuumincreases, the MAP sensor input voltage decreasesproportionally. The sensor also contains electronicsthat condition the signal and provide temperaturecompensation.

The PCM recognizes a decrease in manifold pres-sure by monitoring a decrease in voltage from thereading stored in the barometric pressure memorycell. The MAP sensor is a linear sensor; meaning aspressure changes, voltage changes proportionately.


INTAKE AIR TEMPERATURE SENSOR (Continued)

The range of voltage output from the sensor is usuallybetween 4.6 volts at sea level to as low as 0.3 volts at26 in. of Hg. Barometric pressure is the pressureexerted by the atmosphere upon an object. At sea levelon a standard day, no storm, barometric pressure isapproximately 29.92 in Hg. For every 100 feet of alti-tude, barometric pressure drops 0.10 in. Hg. If a stormgoes through, it can change barometric pressure fromwhat should be present for that altitude. You shouldknow what the average pressure and correspondingbarometric pressure is for your area.

REMOVAL


mounted into the rear of the intake manifold (Fig.17). An o-ring is used to seal the sensor to the intakemanifold (Fig. 19).

(1) Disconnect electrical connector at sensor.(2) Clean area around MAP sensor.(3) Remove sensor mounting screw (TORX head).(4) Remove MAP sensor from intake manifold.(5) Check condition of sensor o-ring (Fig. 19).


mounted into the front of the intake manifold (Fig.18). An o-ring is used to seal the sensor to the intakemanifold (Fig. 19).

(1) Disconnect electrical connector at sensor.(2) Clean area around MAP sensor.(3) Remove 2 sensor mounting screws.(4) Remove MAP sensor from intake manifold.(5) Check condition of sensor o-ring (Fig. 19).

Fig. 17 MAP SENSOR LOCATION-2.4L1 - REAR OF INTAKE MANIFOLD2 - MAP SENSOR3 - ALIGNMENT PIN4 - MOUNTING BOLT (TORX)5 - ELECTRICAL CONNECTOR6 - MAIN ENGINE HARNESS CONNECTORS

Fig. 18 MAP SENSOR / ECT SENSOR - 3.7L1 - MOUNTING SCREWS2 - MAP SENSOR3 - ECT SENSOR

Fig. 19 MAP SENSOR O-RING1 - MAP SENSOR2 - O-RING


MAP SENSOR (Continued)

INSTALLATION


mounted into the rear of the intake manifold. Ano-ring is used to seal the sensor to the intake mani-fold (Fig. 19).

(1) Clean MAP sensor mounting hole at intakemanifold.

(2) Check MAP sensor o-ring seal for cuts or tears.(3) Position sensor into manifold.(4) Install MAP sensor mounting screws. Tighten

screw to 3 N·m (25 in. lbs.) torque.(5) Connect electrical connector.


mounted into the front of the intake manifold (Fig.18). An o-ring is used to seal the sensor to the intakemanifold (Fig. 19).

(1) Clean MAP sensor mounting hole at intakemanifold.

(2) Check MAP sensor o-ring seal for cuts or tears.(3) Position sensor into manifold.(4) Install MAP sensor mounting bolts (screws).

Tighten screws to 3 N·m (25 in. lbs.) torque.(5) Connect electrical connector.

OXYGEN SENSOR

DESCRIPTIONThe Oxygen Sensors (O2S) are attached to, and

protrude into the vehicle exhaust system. Dependingon the engine or emission package, the vehicle mayuse a total of either 2 or 4 sensors.

2.4L Engine: Two sensors are used: upstream(referred to as 1/1) and downstream (referred to as1/2). With this emission package, the upstream sen-sor (1/1) is located just before the main catalytic con-vertor. The downstream sensor (1/2) is located justafter the main catalytic convertor.

3.7L V-6 Engine: On this emissions package, 4sensors are used: 2 upstream (referred to as 1/1 and2/1) and 2 downstream (referred to as 1/2 and 2/2).With this emission package, the right upstream sen-sor (2/1) is located in the right exhaust downpipe justbefore the mini-catalytic convertor. The left upstreamsensor (1/1) is located in the left exhaust downpipejust before the mini-catalytic convertor. The rightdownstream sensor (2/2) is located in the rightexhaust downpipe just after the mini-catalytic con-vertor, and before the main catalytic convertor. Theleft downstream sensor (1/2) is located in the leftexhaust downpipe just after the mini-catalytic con-vertor, and before the main catalytic convertor.

OPERATIONAn O2 sensor is a galvanic battery that provides

the PCM with a voltage signal (0-1 volt) inverselyproportional to the amount of oxygen in the exhaust.In other words, if the oxygen content is low, the volt-age output is high; if the oxygen content is high theoutput voltage is low. The PCM uses this informationto adjust injector pulse-width to achieve the14.7–to–1 air/fuel ratio necessary for proper engineoperation and to control emissions.

The O2 sensor must have a source of oxygen fromoutside of the exhaust stream for comparison. Cur-rent O2 sensors receive their fresh oxygen (outsideair) supply through the O2 sensor case housing.

Four wires (circuits) are used on each O2 sensor: a12–volt feed circuit for the sensor heating element; aground circuit for the heater element; a low-noisesensor return circuit to the PCM, and an input cir-cuit from the sensor back to the PCM to detect sen-sor operation.

Oxygen Sensor Heater Relay - 3.7L Engine: Onthe 3.7L engine, 4 heated oxygen sensors are used. Aseparate oxygen sensor relay is used to supply volt-age to the sensors heating elements for only the 1/2and 2/2 downstream sensors. Voltage for the other 2sensor heating elements is supplied directly from thePowertrain Control Module (PCM) through a PulseWidth Module (PWM) method.

Pulse Width Module (PWM): Voltage to the O2sensor heating elements is supplied directly from thePowertrain Control Module (PCM) through two sepa-rate Pulse Width Module (PWM) low side drivers.PWM is used on both the upstream and downstreamO2 sensors on the 2.4L engine, and only on the 2upstream sensors (1/1 and 2/1) on the 3.7L engine.The main objective for a PWM driver is to avoid over-heating of the O2 sensor heater element. Withexhaust temperatures increasing with time andengine speed, it’s not required to have a full-voltageduty-cycle on the O2 heater elements.

To avoid the large simultaneous current surgeneeded to operate all 4 sensors, power is delayed tothe 2 downstream heater elements by the PCM forapproximately 2 seconds.

Oxygen Sensor Heater Elements:The O2 sensor uses a Positive Thermal Co-efficient

(PTC) heater element. As temperature increases,resistance increases. At ambient temperaturesaround 70°F, the resistance of the heating element isapproximately 4.5 ohms. As the sensor’s temperatureincreases, resistance in the heater element increases.This allows the heater to maintain the optimumoperating temperature of approximately 930°-1100°F(500°-600° C). Although the sensors operate thesame, there are physical differences, due to the envi-


MAP SENSOR (Continued)

ronment that they operate in, that keep them frombeing interchangeable.

Maintaining correct sensor temperature at alltimes allows the system to enter into closed loopoperation sooner. Also, it allows the system to remainin closed loop operation during periods of extendedidle.

In Closed Loop operation, the PCM monitors cer-tain O2 sensor input(s) along with other inputs, andadjusts the injector pulse width accordingly. DuringOpen Loop operation, the PCM ignores the O2 sensorinput. The PCM adjusts injector pulse width basedon preprogrammed (fixed) values and inputs fromother sensors.

Upstream Sensor - 2.4L Engine: The upstreamsensor (1/1) provides an input voltage to the PCM.The input tells the PCM the oxygen content of theexhaust gas. The PCM uses this information to finetune fuel delivery to maintain the correct oxygen con-tent at the downstream oxygen sensor. The PCM willchange the air/fuel ratio until the upstream sensorinputs a voltage that the PCM has determined willmake the downstream sensor output (oxygen content)correct.

The upstream oxygen sensor also provides an inputto determine catalytic convertor efficiency.

Downstream Sensor - 2.4L Engine: The down-stream oxygen sensor (1/2) is also used to determinethe correct air-fuel ratio. As the oxygen contentchanges at the downstream sensor, the PCM calcu-lates how much air-fuel ratio change is required. ThePCM then looks at the upstream oxygen sensor volt-age and changes fuel delivery until the upstreamsensor voltage changes enough to correct the down-stream sensor voltage (oxygen content).

The downstream oxygen sensor also provides aninput to determine catalytic convertor efficiency.

Upstream Sensors - 3.7L Engine: Two upstreamsensors are used (1/1 and 2/1). The 1/1 sensor is thefirst sensor to receive exhaust gases from the #1 cyl-inder. They provide an input voltage to the PCM. Theinput tells the PCM the oxygen content of theexhaust gas. The PCM uses this information to finetune fuel delivery to maintain the correct oxygen con-tent at the downstream oxygen sensors. The PCMwill change the air/fuel ratio until the upstream sen-sors input a voltage that the PCM has determinedwill make the downstream sensors output (oxygencontent) correct.

The upstream oxygen sensors also provide an inputto determine mini-catalyst efficiency. Main catalyticconvertor efficiency is not calculated with this pack-age.

Downstream Sensors - 3.7L Engine: Two down-stream sensors are used (1/2 and 2/2). The down-stream sensors are used to determine the correct air-

fuel ratio. As the oxygen content changes at thedownstream sensor, the PCM calculates how muchair-fuel ratio change is required. The PCM then looksat the upstream oxygen sensor voltage, and changesfuel delivery until the upstream sensor voltagechanges enough to correct the downstream sensorvoltage (oxygen content).

The downstream oxygen sensors also provide aninput to determine mini-catalyst efficiency. Main cat-alytic convertor efficiency is not calculated with thispackage.

Engines equipped with either a downstream sen-sor(s), or a post-catalytic sensor, will monitor cata-lytic convertor efficiency. If efficiency is belowemission standards, the Malfunction Indicator Lamp(MIL) will be illuminated and a Diagnostic TroubleCode (DTC) will be set. Refer to Monitored Systemsin Emission Control Systems for additional informa-tion.

REMOVAL

CAUTION: Never apply any type of grease to theoxygen sensor electrical connector, or attempt anysoldering of the sensor wiring harness.

Refer to (Fig. 20), (Fig. 21) or (Fig. 22) for O2S(oxygen sensor) location.

Fig. 20 OXYGEN SENSORS - 2.4L1 - ELECTRICAL CONNECTORS2 - UPSTREAM SENSOR (1/1)3 - ELECTRICAL CONNECTORS4 - DOWNSTREAM SENSOR (1/2)


OXYGEN SENSOR (Continued)

Fig. 21 OXYGEN SENSORS - UPSTREAM - 3.7L1 - RIGHT UPSTREAM SENSOR (2/1)2 - ELECTRICAL CONNECTORS

3 - LEFT UPSTREAM SENSOR (1/1)4 - ELECTRICAL CONNECTORS

Fig. 22 OXYGEN SENSORS - DOWNSTREAM - 3.7L1 - ELECTRICAL CONNECTORS2 - ELECTRICAL CONNECTORS

3 - LEFT DOWNSTREAM SENSOR (1/2)4 - RIGHT DOWNSTREAM SENSOR (2/2)



WARNING: THE EXHAUST MANIFOLD, EXHAUSTPIPES AND CATALYTIC CONVERTER BECOMEVERY HOT DURING ENGINE OPERATION. ALLOWENGINE TO COOL BEFORE REMOVING OXYGENSENSOR.

(1) Raise and support vehicle.(2) Disconnect wire connector from O2S sensor.

CAUTION: When disconnecting sensor electricalconnector, do not pull directly on wire going intosensor.

(3) Remove O2S sensor with an oxygen sensorremoval and installation tool.

(4) Clean threads in exhaust pipe using appropri-ate tap.

INSTALLATIONThreads of new oxygen sensors are factory coated

with anti-seize compound to aid in removal. DONOT add any additional anti-seize compound tothreads of a new oxygen sensor.

(1) Install O2S sensor. Tighten to 30 N·m (22 ft.lbs.) torque.

(2) Connect O2S sensor wire connector.(3) Lower vehicle.

THROTTLE BODY

DESCRIPTIONThe throttle body is located on the intake manifold.

Fuel does not enter the intake manifold through thethrottle body. Fuel is sprayed into the manifold bythe fuel injectors.

OPERATIONFiltered air from the air cleaner enters the intake

manifold through the throttle body. The throttle bodycontains an air control passage controlled by an IdleAir Control (IAC) motor. The air control passage isused to supply air for idle conditions. A throttle valve(plate) is used to supply air for above idle conditions.

Certain sensors are attached to the throttle body.The accelerator pedal cable, speed control cable andtransmission control cable (when equipped) are con-nected to the throttle body linkage arm.

A (factory adjusted) set screw is used to mechani-cally limit the position of the throttle body throttleplate. Never attempt to adjust the engine idlespeed using this screw. All idle speed functions arecontrolled by the PCM.

REMOVAL

2.4LA (factory adjusted) set screw is used to mechani-

cally limit the position of the throttle body throttleplate. Never attempt to adjust the engine idlespeed using this screw. All idle speed functions arecontrolled by the Powertrain Control Module (PCM).

(1) Remove air cleaner tube at throttle body.(2) Disconnect throttle body electrical connectors

at IAC motor and TPS.(3) Remove all control cables from throttle body

(lever) arm. Refer to the Accelerator Pedal and Throt-tle Cable section for removal/installation procedures.

(4) Disconnect necessary vacuum lines at throttlebody.

(5) Remove 3 throttle body mounting bolts (Fig.23).

(6) Remove throttle body from intake manifold.(7) Check condition of old throttle body-to-intake

manifold o-ring.

3.7LA (factory adjusted) set screw is used to mechani-

cally limit the position of the throttle body throttleplate. Never attempt to adjust the engine idlespeed using this screw. All idle speed functions arecontrolled by the Powertrain Control Module (PCM).

(1) Remove air cleaner tube at throttle body.(2) Disconnect throttle body electrical connectors

at IAC motor and TPS.

Fig. 23 THROTTLE BODY MOUNTING BOLTS - 2.4L1 - THROTTLE BODY2 - IGNITION COIL3 - MOUNTING BOLTS (3)



(3) Remove all control cables from throttle body(lever) arm. Refer to the Accelerator Pedal and Throt-tle Cable section for removal/installation procedures.

(4) Disconnect necessary vacuum lines at throttlebody.

(5) Remove 3 throttle body mounting bolts (Fig.24).

(6) Remove throttle body from intake manifold.(7) Check condition of old throttle body-to-intake

manifold o-ring (Fig. 25).

INSTALLATION

2.4L(1) Check condition of throttle body-to-intake man-

ifold o-ring. Replace as necessary.(2) Clean mating surfaces of throttle body and

intake manifold.

(3) Install throttle body-to-intake manifold o-ring.(4) Install throttle body to intake manifold.(5) Install 3 mounting bolts. Tighten bolts to 12

N·m (105 in. lbs.) torque.(6) Install control cables.(7) Install electrical connectors.(8) Install necessary vacuum lines.(9) Install air cleaner duct at throttle body.

3.7L(1) Check condition of throttle body-to-intake man-

ifold o-ring. Replace as necessary.(2) Clean mating surfaces of throttle body and

intake manifold.(3) Install throttle body-to-intake manifold o-ring.(4) Install throttle body to intake manifold.(5) Install 3 mounting bolts. Tighten bolts to 12

N·m (105 in. lbs.) torque.(6) Install control cables.(7) Install electrical connectors.(8) Install necessary vacuum lines.(9) Install air cleaner duct at throttle body.

Fig. 24 THROTTLE BODY MOUNTING BOLTS - 3.7L1 - THROTTLE BODY2 - MOUNTING BOLTS (3)

Fig. 25 THROTTLE BODY O-RING - 3.7L1 - INTAKE MANIFOLD2 - THROTTLE BODY O-RING


THROTTLE BODY (Continued)

THROTTLE CONTROL CABLE

REMOVAL

2.4L

CAUTION: Be careful not to damage or kink thecable core wire (within the cable sheathing) whileservicing accelerator pedal or throttle cable.

(1) From inside vehicle, hold up accelerator pedal.Remove plastic cable retainer (clip) and throttle cablecore wire from upper end of pedal arm (Fig. 26).Plastic cable retainer snaps into top of pedal arm.

(2) Remove cable core wire at pedal arm.(3) From inside vehicle, remove metal clip holding

cable to dashpanel (Fig. 26).(4) Remove air box at throttle body.(5) Unsnap cable from dashpanel routing clip.(6) Remove cable housing from dash panel and

pull into engine compartment.(7) Hold throttle in wide open position. While held

in this position, slide throttle cable pin (Fig. 27) fromthrottle body bellcrank.

(8) Using a pick or small screwdriver, press releasetab (Fig. 27) to release plastic cable mount frombracket. Press on tab only enough to releasecable from bracket. If tab is pressed too much,it will be broken.To remove throttle cable fromthrottle body bracket, slide cable towards front ofvehicle.

(9) Remove throttle cable from vehicle.

3.7L

CAUTION: Be careful not to damage or kink thecable core wire (within the cable sheathing) whileservicing accelerator pedal or throttle cable.

(1) From inside vehicle, hold up accelerator pedal.Remove plastic cable retainer (clip) and throttle cablecore wire from upper end of pedal arm (Fig. 28).Plastic cable retainer snaps into top of pedal arm.

(2) Remove cable core wire at pedal arm.(3) From inside vehicle, remove metal clip holding

cable to dashpanel (Fig. 28).(4) Remove air box at throttle body.(5) Unsnap cable from dashpanel routing clip.(6) Remove cable housing from dash panel and

pull into engine compartment.(7) Hold throttle in wide open position. While held

in this position, slide throttle cable pin (Fig. 29) fromthrottle body bellcrank.

Fig. 26 ACCELERATOR PEDAL/BRACKETASSEMBLY

1 - METAL THROTTLE CABLE CLIP2 - THROTTLE CABLE3 - PLASTIC CABLE RETAINER4 - PEDAL/BRACKET ASSEMBLY5 - PEDAL MOUNTING NUTS (2)6 - PEDAL MOUNTING STUDS (2)

Fig. 27 THROTTLE CABLE, PIN, RELEASE TAB-2.4L1 - MOUNTING BRACKET2 - SPEED CONTROL CABLE3 - THROTTLE CABLE4 - RELEASE TAB5 - CABLE PINS6 - BELLCRANK


(8) Using a pick or small screwdriver, press releasetab (Fig. 30) to release plastic cable mount frombracket. Press on tab only enough to releasecable from bracket. If tab is pressed too much,it will be broken. Slide plastic mount (Fig. 30)towards right side of vehicle to remove throttle cablefrom throttle body bracket.

(9) Remove throttle cable from vehicle.

INSTALLATION(1) Slide accelerator cable plastic mount into throt-

tle body mounting bracket. Continue sliding untilrelease tab (Fig. 30) is aligned to hole in mountingbracket.

(2) Hold throttle in wide open position. While heldin this position, slide throttle cable pin (Fig. 29) intothrottle body bellcrank.

(3) Push cable housing into rubber grommet andthrough opening in dash panel.

(4) From inside vehicle, install metal clip holdingcable to dashpanel (Fig. 28).

(5) From inside vehicle, slide throttle cable corewire into opening (slot) in top of pedal arm.

(6) Push plastic cable retainer (clip) into pedal armopening until it snaps in place.

(7) Install air box to throttle body.(8) Before starting engine, operate accelerator

pedal to check for any binding.

Fig. 28 ACCELERATOR PEDAL/BRACKETASSEMBLY

1 - METAL THROTTLE CABLE CLIP2 - THROTTLE CABLE3 - PLASTIC CABLE RETAINER4 - PEDAL/BRACKET ASSEMBLY5 - PEDAL MOUNTING NUTS (2)6 - PEDAL MOUNTING STUDS (2)

Fig. 29 THROTTLE CABLE PIN-3.7L1 - THROTTLE CABLE PIN2 - THROTTLE BODY BELLCRANK3 - PUSH UP HERE

Fig. 30 THROTTLE CABLE RELEASE TAB-3.7L1 - THROTTLE CABLE2 - RELEASE TAB3 - PICK OR SCREWDRIVER4 - PLASTIC CABLE MOUNT


THROTTLE CONTROL CABLE (Continued)

THROTTLE POSITION SENSOR

DESCRIPTIONThe 3–wire Throttle Position Sensor (TPS) is

mounted on the throttle body and is connected to thethrottle blade shaft.

OPERATIONThe 3–wire TPS provides the Powertrain Control

Module (PCM) with an input signal (voltage) thatrepresents the throttle blade position of the throttlebody. The sensor is connected to the throttle bladeshaft. As the position of the throttle blade changes,the output voltage of the TPS changes.

The PCM supplies approximately 5 volts to theTPS. The TPS output voltage (input signal to thePCM) represents the throttle blade position. ThePCM receives an input signal voltage from the TPS.This will vary in an approximate range of from .26volts at minimum throttle opening (idle), to 4.49 voltsat wide open throttle. Along with inputs from othersensors, the PCM uses the TPS input to determinecurrent engine operating conditions. In response toengine operating conditions, the PCM will adjust fuelinjector pulse width and ignition timing.

The PCM needs to identify the actions and positionof the throttle blade at all times. This information isneeded to assist in performing the following calcula-tions:

• Ignition timing advance• Fuel injection pulse-width• Idle (learned value or minimum TPS)• Off-idle (0.06 volt)• Wide Open Throttle (WOT) open loop (2.608

volts above learned idle voltage)• Deceleration fuel lean out• Fuel cutoff during cranking at WOT (2.608 volts

above learned idle voltage)• A/C WOT cutoff (certain automatic transmis-

sions only)

REMOVAL

2.4LThe Throttle Position Sensor (TPS) is mounted to

the throttle body (Fig. 31).(1) Disconnect TPS electrical connector.(2) Remove 2 TPS mounting screws.(3) Remove TPS.




the throttle body (Fig. 32), or (Fig. 33).(1) Disconnect TPS electrical connector.(2) Remove 2 TPS mounting screws.(3) Remove TPS.

INSTALLATION


the rear of the throttle body.The throttle shaft end of the throttle body slides

into a socket in the TPS (Fig. 33). The TPS must beinstalled so that it can be rotated a few degrees. (Ifsensor will not rotate, install sensor with throttleshaft on other side of socket tangs). The TPS will beunder slight tension when rotated.

(1) Install TPS and retaining screws.(2) Tighten screws to 7 N·m (60 in. lbs.) torque.(3) Connect TPS electrical connector to TPS.

(4) Manually operate throttle (by hand) to checkfor any TPS binding before starting engine.

(5) Install air cleaner tube to throttle body.


the throttle body (Fig. 32).The throttle shaft end of the throttle body slides

into a socket in the TPS (Fig. 33). The TPS must beinstalled so that it can be rotated a few degrees. (Ifsensor will not rotate, install sensor with throttleshaft on other side of socket tangs). The TPS will beunder slight tension when rotated.

(1) Install TPS and retaining screws.(2) Tighten screws to 7 N·m (60 in. lbs.) torque.(3) Connect TPS electrical connector to TPS.(4) Manually operate throttle (by hand) to check

for any TPS binding before starting engine.(5) Install air cleaner tube to throttle body.


Fig. 33 TPS INSTALLATION - 3.71 - THROTTLE BODY2 - TPS3 - THROTTLE BODY SHAFT4 - SOCKET LOCATING TANGS


THROTTLE POSITION SENSOR (Continued)

Jeep liberty 2002 2005 fuel system

Automotive

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