Sensores 3500B EUI

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777D

Service TrainingMALAGA

ELECT. ENG. CONTROL

ThorbenMARCH 1998

IV. 3500B EUI



CHAPTER : 3500B

AIR INTAKE AND EXHAUST

ELECT. ENG. CONTROL

2Page:

This sectional view of the engine shows the injector installation and the pushrod arrangement in

relation to the upper portion of the engine.

This sectional view is similar to the original 3500 EUI engine. Major differences are the spring

loaded injector push rods and the larger diameter camshaft.

Each cylinder has three corresponding camshaft lobes. The center lobe is is used to actuate the

unit injector. The 3500B has a larger diameter camshaft to accommodate the higher injection

pressures generated in the unit injector pumps.

The cylinder block has a larger camshaft bore to accommodate the larger camshaft. (All 3500

engines are now being manufactured to this standard.)

The 3500B injector pushrod spring, which maintains contact between the lifter roller and the

camshaft lobe. This spring is designed to maintain cam follower and camshaft contact andprotect the mechanism during a possible overspeed



CHAPTER : 3500B

CYLINDER HEADS

ELECT. ENG. CONTROL

3Page:

MUI EUI

This picture shows the difference between the Mechanical Unit Injection (MUI) and current Electronic

Unit Injection (EUI) installation in the cylinder head.

Notice the Helper Spring on the injector pushrod. This arrangement is designed to keep the follower in

constant contact with the camshaft. The helper spring is required due to the increased injection pressures

of 151 MPa (22000 psi) and the steeper, high lift camshaft lobe profile.



4

P a g e:

FUELTANK

PRIMARYFUEL

FILTER

FUEL

PRESSUREREGULATOR

FUELTRANSFER

PUMP

ECM

CYLINDERHEAD

PRIMING PUMP SUPPLY

DIFFERENTIALPRESSURE

SWITCH

RETURN FUEL



CHAPTER : 3500B

FUEL SUPPLY SYSTEM

ELECT. ENG. CONTROL

5Page:

PRIMARYFILTER

TRANSFERPUMP

SECONDARYFILTER

FUEL TANK

ECM

FUEL TANK

FUELPRESSURE

REGULATOR

This view shows the injector and its fuel supply circuit. A larger volume of fuel passes through the

injector than is required for injection. This extra flow is used to cool the injector, which is also

surrounded by coolant.



CHAPTER : 3500B

COMPONENT DIAGRAM - 777D

ELECT. ENG. CONTROL

6Page:

T O

P R E L U B R I C A T I O N

P U M P

+ B A T T E R Y G

R O

U N D

B O

L T

1 5 A M P

B R E A K E R

K E Y S T A R

T

S W I T C H

2 4 V

P 2 0 / J 2 0

S P E E D / T I M I N G

S E N S O R

J 3 / P 3 M A C H I N E

I N T E R F A C E

C O N N E C T O R

C O O L A N T

T E M P E R A T U

R E

S E N S O R

8 / 1 2 / 1 6

I N J E C T O R S

G R O

U N D B O L T

P 2 6 T / C

C O N N E C T O R

J 4 / P 4 T H R O U G H

J 1 9 / P 1 9

J 2

J 1

E C M

U N F I L T E R E D O I L

P R E S S U R E

S E N S O R

A F T E R C O O L E

R

T E M P E R A T U R

E

S E N S O R

C R A N K C A S E

P R E S S U R E

S E N S O R

J

2 9 / P 2 9

R I G H T

T U R B O C H A R G E R

I N L E T P R E S S U R E

S E N S O R

J

2 5 / P 2 5

L O W O

I L

L E V E L

S W I T C H

A T M O S P H E R I C

P R E S S U R E

S E N S O R

F U E L F I L T E

R

D I F F E R E N T I A L

P R E S S U R E S W

I T C H


O U T L E T

P R E S S U R E S E N S O R

J

2 3 / P 2 3

C O O L A N T

F L O W

S W I T C H

F I L T E R E D O I L

P R E S S U R E

S E N S O R

J 2 2 / P 2 2

L E F T

T U R B O C H A R G

E R

E X H A U S T

T E M P E R A T U R E

S E N S O R

R I G H T

T U R B O C H A R G

E R

E X H A U S T

T E M P E R A T U R E

S E N S O R

L E F T


I N L E T P R E S S U R E

S E N S O R

J 2 8 / P 2 8

J 3 5 / P 3 5

T H R O T T L E

P O S I T I O N

S E N S O R

T H R O T T L E

B A C K - U P

S W I T C H

U S E R D E F I N E D S H U T D O W

N

G R O U N D

L E V E L

S H U T D O W

N

S W I T C H

B A T T E R Y

E N G I N E F A N

C O N T R O

L

S O L E N O I

D

A / C

O N

S W I T

C H

F A N S P E E D S E N S O R

+ B A T T E R Y

R E L A Y

C Y L I N D

E R

E N G I N E

E T H E R S T A R T V A L V E

S T A R T I N G

A I D S W I T C H

J 2 1 / P 2 1

J 3 2 / P 3 2

J 1 0 5 / P 1 0 5

J 1 0 6 / P 1 0 6

J 4 7 / P 4 7

P 3 0 / J 3 0

J 2 7 / P 2 7

J 4 8 / P 4 8

P 8 4 / J 8 4

P 4 1 / J 4 1

3 0 8 - Y L

1 1 3 - O R

B A S I C E N G I N E B L O C K D I A G R A M

A P P L I C A T I O N

B L O C K D I A G R A M

E L E C T R O N I C S E R V I C E

T O O L C O N N E C T O R

M O N

I T O R I N G S Y S T E M

D I S C O N N E C T

S W I T C H

1 5 A M P

B R E A K E R

C O O L A N T

T E M P E R A T U

R E

S E N S O R

J 4 / P 4 T H R O U G H

J 1 9 / P 1 9

R E L A Y

J 2 1 / P 2 1

J 4 7 / P 4 7

P 3 1 / J 3 1

0 5

1 0

1 5

2 0

2 5

3 0

X 1 0 0

2 4 V

M P H

k m

/ h

4 4

A U T

P

R

C A T D a t a

L i m k



CHAPTER : 3500B

ANALOG SENSOR POWER SUPPLY

ELECT. ENG. CONTROL

7Page:

P22 J22

ENGINE COOLANTTEMPERATURE SENSOR

FILTERED OILPRESSURE SENSOR

+V ANALOGANALOG RETURNSIGNAL


P23 J23

TURBO OUTLETPRESSURE SENSOR


P25 J25

RIGHT TURBO INLET PRESSURE SENSOR


P27 J27

ATMOSPHERICPRESSURE SENSOR


P28 J28

LEFT TURBO INLETPRESSURE SENSOR


3630

P1 J1

P43 J43


CRANKCASEPRESSURE SENSOR

P48 J48


UNFILTERED OILPRESSURE SENSOR

ABC

ABC

ABC

ABC

ABC

ABC

ABC

ABC

J21 P21

5 ± 0.5 VOLTS

+V ANALOG SUPPLYANALOG RETURN

ECM

The Analog Sensor Power Supply provides power to all the analog sensors (pressure and temperature).

The ECM supplies 5.0 ± 0.5 Volts DC (Analog Supply) through the J1/P1 connector to each sensor.

A power supply failure will cause all analog sensors to appear to fail.

The power supply is protected against short circuits, which means that a short in a sensor or a wiring

harness will not cause damage to the ECM.



CHAPTER : 3500B

DIGITAL SENSOR POWER SUPPLY

ELECT. ENG. CONTROL

8Page:

+ V DIGITAL SUPPLY- V DIGITAL RETURN

2935

P1 J1

ABC

J31 P31

+V DIGITALDIGITAL RETURN

SIGNAL

RIGHT EXHAUST TEMPERATURE SENSOR

ABC

J35 P35

THROTTLEPOSITION SENSOR


SIGNAL

8 ± 0.5 VOLTS

ABC

J30 P30


SIGNAL

LEFT EXHAUST TEMPERATURE SENSOR

AB

C

J84 P84


SIGNAL

FAN SPEED SENSOR

ECM

The ECM supplies power at 8 ± 0.5 Volts through the J1/P1 connector to the following circuits:

- Throttle Position Sensor

- Fan Speed Sensor (if installed)

- Exhaust Temperature Sensors

The power supply is protected against short circuits, which means that a short in a sensor will not cause

damage to the ECM



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

9Page:

SYSTEM POWER SUPPLIES

The 3500B EUI system has one external and five internal power supplies with various voltages as shown.

EXTERNAL POWER SUPPLIES

ECM power supply 24 Volts

INTERNAL POWER SUPPLIES

Speed/Timing Sensor power supply 12.5 Volts

Injector power supply 105 Volts

Analog Sensor power supply 5 Volts

Digital Sensor power supply 8 Volts

Wastegate Control Solenoid power supply 0 - 24 Volts

ECM Power Supply

The power supply to the ECM and the system is drawn from the 24-Volt machine battery. The principle

components in this circuit are:

- Battery

- Key Start Switch

- Main Power Relay

- 15 Amp Breaker

- Ground Bolt

- ECM Connector (P1/JI)

- Machine Interface Connector (J3/P3)

If the supply voltage exceeds 32.5 Volts or is less than 9.0 Volts, a diagnostic code is logged. (See the

Troubleshooting Guide for complete details on voltage event logging.)

NOTE: The Ground Bolt and the Machine Interface Connector are the only power supply

components mounted on the engine.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

10Page:

Injector Power Supplies

The injectors are supplied with power from the ECM at 105 Volts. For this reason, precautions must be

observed when performing maintenance around the valve covers.

On the 3512B and 3516B, two of the internal power supplies are used for the injectors. If a failure

occurs, only one bank of injectors could have failed. On the 3508B, only one of the internal power

supplies is used. As previously mentioned, the same ECM is used on all three configurations.

If an open or a short occurs in the injector circuit, the ECM will disable that injector. The ECM will

periodically try to actuate that injector to determine if the fault is still present and will disconnect orreconnect the injector as appropriate.

Speed/Timing Sensor

One Speed/Timing Sensor is installed and it serves four basic functions in the system:

- Engine speed detection

- Engine timing detection

- Cylinder and TDC identification

- Reverse rotation protection

The ECM supplies 12.5 ± 1 Volts to the Speed/Timing Sensor.

Connector pins A and B transmit the common power supply to the sensor. The C connector pin transmits

the signals from the sensor to the ECM.

This power supply is not battery voltage, but is generated and regulated within 1.0 Volt by the ECM.

This power supply and the Speed/Timing Sensor are vital parts of the EUI system. A failure of the sensor

will result in an engine shutdown.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

11Page:

The Speed/Timing Sensor is mounted on the rear housing and is

self-adjusting during installation.

This type of sensor does not have a typical fixed air gap. However, the sensor is not in direct contact with

the timing wheel, but does run with zero clearance. A Speed/Timing Sensor failure will cause an engine

shutdown.

The sensor may be functionally checked by cranking the engine and observing the service tool status

screen for engine rpm.

A sensor failure will be indicated by the active fault screen on the service tool. An intermittent failurewill be shown in the logged fault screen.

The sensor has a dedicated power supply. A power supply failure at the ECM will cause the sensor to

fail.

The sensor head is extended prior to installation. The action of screwing in the sensor pushes the head

back into the body after the head contacts the timing wheel.

During installation, it is essential to check that the sensor head is not aligned with a wide slot in the

timing wheel. If this condition occurs, the head will be severed when the engine is started, and somedisassembly may be necessary to remove the debris.

Timing calibration is normally performed after the following procedures:

1. ECM replacement

2. Speed/timing sensor replacement

3. Engine timing adjustment

4. Camshaft, crankshaft or gear train replacement



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

12Page:

The engine Coolant Temperature Sensor is located at the front of the engine on the thermostat housing.

This sensor is used with the ECM to control various functions. The following systems or circuits use the

Temperature Sensor output to the ECM:

The Vital Information Management System (VIMS) or Caterpillar Monitoring System Coolant

Temperature Gauge over the CAT Data Link.

The High Coolant Temperature Warning Alert Indicator and Gauge on the VIMS or Caterpillar

Monitoring System panel. (The information is transmitted over the CAT Data Link.)

The Engine Demand Fan Control, if installed, uses the sensor signal reference to provide the

appropriate fan speed.

The Cat Electronic Technician (ET) status screen for coolant temperature indication.

The Cold Mode engine control (i.e. elevated low idle and timing reference for cold mode operation).

The Ether Aid control as a reference for Ether Aid operation.

The sensor supplies the temperature signal for the following functions:

- Caterpillar Monitoring System or VIMS instrument display, warning lamps and alarm

- Demand Control Fan (if so equipped)

- ET or ECAP coolant temperature display- High coolant temperature event logged above 107°C (225°F)

- Engine Warning Derate when 107°C (225°F) is exceeded or low oil pressure occurs (if so

equipped)

- Reference temperature for Cold Mode operation

NOTE: All analog sensors use the common analog power supply of 5.0 ± 0.2 Volts.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

13Page:

The Aftercooler Temperature Sensor is mounted at the rear of the block (Off-highway Truck) and

measures coolant temperature in the aftercooler circuit.

The ECM uses the sensor signal as a reference for the fan control. When high aftercooler temperatures

are reached, the cooling fan speed is increased. Very high aftercooler temperatures will cause a VIMS

warning event to be logged.

NOTE: This sensor measures the ability of the aftercooler to cool the air sufficiently for

combustion. As a general rule, for every 1 degree that the combustion air is reduced in

temperature, the exhaust will be reduced by approximately 3 degrees. High inlet manifold

temperatures can significantly shorten the life of exhaust system components (i.e. exhaustmanifolds, valves, turbochargers and pistons).

Three pressure sensors are used for the measurement of oil pressure:

- Two Oil Pressure Sensors (filtered and unfiltered)

- Atmospheric Pressure Sensor

The filtered and unfiltered pressure sensors are used together to measure oil filter restriction.

The filtered oil pressure sensor is used to measure lubrication oil pressure for the operator on the dash

panel and for the technician on ET. The atmospheric pressure sensor is used with this oil pressure sensorto calculate the gauge pressure reading.



CHAPTER : 3500B

OIL PRESSURE MAP

ELECT. ENG. CONTROL

14Page:

O I L P R E S S

U R E I N k P a

600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 180060

80

100

120

140

160

180

200

220

240

260

280

300

ENGINE RPM

1900

320

340

8.7

11.6

14.5

17.4

20.3

23.2

26.1

29

31.9

34.8

37.7

40.6

43.5

46.4

49.3

O I L P R E S S

U R E I N P S I

kPa x 0.145 = PSI

2000

Engine oil pressure varies with engine speed. As long as oil pressure increases above the upper line after

the engine has been started and is running at low idle, the ECM reads adequate oil pressure. No faults are

indicated and no logged event is generated. A delay built into the system prevents false events from

being logged after start-up or after a filter change.

If the engine oil pressure decreases below the lower line, the following occurs:

- An event is generated and logged in the permanent ECM memory.

- A Category 3 Warning (alert indicator, action lamp and alarm) is generated on the VIMS and

Caterpillar Monitoring System.

- The engine is derated (if so equipped) to alert the operator.

The width of the pressure band between the two lines is sufficient to prevent multiple alarms and events

or a flickering warning lamp. (This pressure separation is referred to as hysteresis).



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

15Page:

The Atmospheric Pressure Sensor is installed on the ECM mounting adapter and is vented to the

atmosphere. This sensor has various functions which are fully described later in the presentation.

Briefly, it performs the following functions:

Ambient pressure measurement for automatic altitude compensation and automatic air filter

compensation.

Absolute pressure measurement for the fuel ratio control, ET, filter restriction, and Caterpillar

Monitoring System panel (gauge) pressure calculations.

All pressure measurements require the atmospheric pressure sensor to calculate gauge pressure. All

pressure sensors in the system measure absolute pressure. The sensors are used individually in the case

of atmospheric pressure (absolute pressure measurement). They are used in pairs to calculate gauge

pressures (oil and boost) and filter restriction.

All the pressure sensor outputs are matched to the Atmospheric Pressure Sensor output during

calibration. Calibration can be accomplished automatically using the ET service tool or by turning on the

key start switch without starting the engine for five seconds. The Atmospheric Pressure Sensor performs

four main functions:

1. Automatic Altitude Compensation (Maximum derate 24%)

2. Automatic Filter Compensation (Maximum derate 20%)

3. Part of the pressure calculation for gauge pressure readings

4. Reference sensor for pressure sensor calibration

A foam filter is installed below the sensor to prevent the entry of dirt.



CHAPTER : 3500B

ENGINE POWER DERATING MAP

ELECT. ENG. CONTROL

16Page:

100%

98%

96%

94%

92%

90%

88%

86%

84%

82%

80%

78%

76%

74%

77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53

8,210

8,920

9,630

10,340

11,050

11,760

12,470

13,890

14,600

15,310

16,020

16,730

17,440

13,180

7,500

72%

ACCORDING TO ATMOSPHERIC PRESSURE

ATMOSPHERIC PRESSURE IN kPa

P E R C E N T O F F U L L L O A D P O W E R

A L T I T U D E I N F E E T

Atmospheric pressure measurement by the sensor provides an altitude reference for the purpose of

Automatic Altitude Compensation.

The graph shown here describes how derating on a typical 3500B starts at 7500 ft. and continues linearlyto a maximum of 17000 ft. Other engines may start between 4000 and 12000 ft. depending on theapplication.

The advantage of the EUI system is that the engine always operates at the correct derating setting at allaltitudes. The system continually adjusts to the optimum setting regardless of altitude, so the engine will

not exhibit a lack of power or have smoke problems during climbs or descents to different altitudes.

NOTE: The EUI system has an advantage over a mechanical fuel system which is derated in"altitude blocks" (i.e. 7500 ft., 10000 ft., 12500 ft.). EUI derating is continuous and automatic.Therefore, a machine operating in the lower half of the block is not penalized with low power.Conversely, a machine operating in the upper half of the block will not overfuel with the EUIsystem.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

17Page:

The Turbocharger Inlet Pressure Sensor is mounted between the air filter and the turbocharger.

This sensor is used in conjunction with the atmospheric pressure sensor to measure air filter restriction for

engine protection purposes. The difference between the two pressure measurements is used as the filter

differential pressure. The engine ECM uses this calculation to determine whether derating is necessary to

protect the engine against the effects of excessive filter restriction.

This function is referred to as Automatic Air Filter Compensation.

Depending on the application and air intake system configuration, either one or two Turbocharger Inlet

Pressure Sensors may be used.

If the machine is equipped with an ether start system, the ECM will automatically inject ether from the

ether cylinders) during cranking. The operator can also inject ether manually with the ether switch in the

cab. Ether will only be injected if the engine coolant temperature is below 10°C (50°F) and engine speed

is below 1200 rpm.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

18Page:

Automatic Filter Compensation means that the engine is protected against the effects of plugged filters.Derating is automatic as follows:

- Air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water)

- Engine power derating starts at the rate of 2% per 1 kPa of ∆P

- Maximum derate 20%

- Event is logged when air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water)

These ∆P specifications are typical examples. The actual values may vary depending on the application.

Derating is retained at the maximum ∆P until the key start switch is cycled off and on.

NOTE: If only one filter is plugged, the ET service tool and Caterpillar Monitoring System will

display the highest ∆P of the two. Derating is also based on the highest ∆P of the two.

The Turbocharger Outlet Pressure Sensor measures absolute pressure downstream of the aftercooler.

Boost (gauge) pressure can be read with the service tools. This measurement is a calculation using the

Atmospheric Pressure and the Turbocharger Outlet Pressure Sensors.

A failure of this sensor will cause the ECM to default to a zero boost condition. This failure can result in

a 60% loss in engine power.

The function of the sensor is to enable the Air/Fuel Ratio Control which reduces smoke, emissions and

maintains engine response during acceleration. The system utilizes manifold pressure and engine speed

to control the air/fuel ratio. Engine fuel delivery is limited according to a map of gauge turbo outlet

pressure and engine speed.

The Air/Fuel Ratio Control setting is adjustable on 3500B machine applications using the service tool.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

19Page:

The ECM uses gauge pressure measured from the Crankcase Pressure Sensor and the Atmospheric

Pressure Sensor to determine whether crankcase pressure is excessive (i.e. a piston allowing excessive

blowby which could soon cause considerable damage).

The ECM will warn the operator of possible damaging conditions and record adverse conditions in the

memory.

A possible cause of excessive crankcase pressure could be piston damage or a piston ring failure. An

early warning means that the engine can be shut down without catastrophic secondary damage.

Crankcase pressure is compared with atmospheric pressure. The result is crankcase (gauge) pressure (i.e.

pressure above ambient).

The trip points are:

WARNING 2 kPa (10 in. of water)

EVENT 3.5 kPa (17in. of water)

A Crankcase Pressure Sensor is mounted on the right side of the engine.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

20Page:

Two Exhaust Temperature Sensors are installed on the 793C. The sensors are mounted between the

exhaust manifold and the turbocharger.

The ECM uses the sensors to warn the operator of possibly damaging conditions and logs an event in the

memory.

An engine derate occurs on Off-highway Trucks if excessive exhaust temperatures are reached.

The Throttle Position Sensor provides engine speed control for the operator.

At engine start-up, the engine rpm is set to low idle for two seconds to allow an increase of oil pressure

before the engine is accelerated.

The Throttle Position Sensor receives 8 Volts from the Digital Sensor Power Supply at the ECM.

The Throttle Position Sensor is shown on the machine wiring side of the diagram.

NOTE: This system eliminates all mechanical linkage between the operator's engine speed controls

and the governor (ECM).



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

21Page:

Demand Fan Controls

Two types of thermostatic fans are used in 3500B machine applications. Some Off-highway Trucks and

Track-type Tractors are equipped with a variable speed fan drive clutch. Some Wheel Loaders are

equipped with a hydraulic fan drive.

Both systems use the ECM and the temperature sensor as the engine coolant temperature reference, and

both are controlled by the ECM. If an electrical failure of the system occurs, the fan will go to maximum

(100%) speed.

The advantages of the systems are:

- Reduced fuel consumption in most conditions

- Reduced engine overcooling at low ambient temperatures

- Faster engine warm-up

- More engine power available at the flywheel

- Reduced noise

Engine Mounted Switches

Three EUI circuit switches are mounted on the engine:

The Low Oil Level Switch signals the ECM if the engine oil level decreases below a predetermined

level. The ECM then warns the operator of possible damaging conditions and logs an event.

The Filter Differential Pressure Switch signals the ECM if the pressure across engine fuel filter is

excessive and the filter needs to be changed.

The Coolant Flow Switch provides the operator with a warning if a failure in the coolant circuit causing

no flow occurs. The switch contacts are normally open with no flow.

The Coolant Flow Switch, like the Oil Level Switch, is a passive sensor (i.e. no power supply) which

means that the ECM cannot determine if the switch or associated circuit has failed. A system problem

could be determined if coolant flow is indicated with the engine stopped or if no coolant flow is indicated

with the engine running.

The functions of these switches may be checked using the status screen. The Coolant Flow Switch

should indicate if flow is present. This function should be checked both with the engine running and

stopped.



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

22Page:

The Throttle Back-up Switch provides a "limp home" mode in the event that the Throttle Position

Sensor becomes inoperative.

If the ECM detects either an invalid or no signal, the Throttle Back-up Switch is automatically activated.

When activated, the operator may operate the switch to raise the engine speed to 1200 rpm for as long as

the switch is operated. If the Throttle Position Sensor signal is received again, the switch is deactivated.

Engine Shutdown Systems

The Ground Level Shutdown Switch is connected to the ECM through the machine and engine wiring

harnesses.

The switch signals the ECM to cut electrical power to the injectors, but maintains power to the ECM.

This feature also enables the engine to be cranked without starting for maintenance purposes.

No other circuits may be connected to this system. The user defined shutdown feature may be used in

conjunction with other circuits.

The User Defined Shutdown feature (if installed) may be used to connect another device to the system to

shut down the engine (such as a customer installed fire suppression system). When the shutdown input is

grounded for one second, the engine will stop running. The input must be pulled down below 0.5 Volts

before the ECM will recognize the shutdown signal.

Operation of the User Defined Shutdown is logged as an event and can also be shown on the ET status

screen.

For example, when installed on an Off-highway Truck, this feature is programmed to function only

during the following conditions:

Parking brake is ENGAGED

Transmission is in NEUTRAL

Machine ground speed is at zero

Not all machines will have this feature installed



CHAPTER : 3500B

COMPONENT DIAGRAM

ELECT. ENG. CONTROL

23Page:

Ether Injection System

The ECM controls the use of ether for cold starting. The ECM uses inputs from the speed/timing and

coolant temperature sensors to determine the need for ether.

The ECM cycles the ether for three seconds on and three seconds off. Actual flow is determined by

engine speed and temperature. Ether injection is disabled when the coolant temperature exceeds 10°C

(50°F) or engine speed exceeds 1200 rpm.

A manual mode allows ether injection when the above parameters permit. In the manual mode, a

continuous flow of ether is injected. The ether injection status can be read on the ET status screen.

Prelubrication System

The ECM controls the prelubrication system. This system uses the coolant temperature, engine speed and

oil pressure as its references to determine the need for prelubrication.

The system is activated when the key start switch is turned to the start position. The system prevents

starter motor engagement until the oil pressure increases.



CHAPTER : 3500B

LOGGED EVENTS

ELECT. ENG. CONTROL

24Page:

Logged events listed on the appropriate ET screen are conditions which are abnormal to the operation of

the engine. For example:

- High coolant temperature

- Low oil pressure

- Filter restriction

- Excessive engine speed

These events are not normally electronic problems, but might be conditions caused by a plugged radiator,

low oil level, maintenance or operator deficiencies.

A list of possible events for the 3500B engine is included on the next page.

Some of the parameters listed in this presentation are used in the ET events list. They are as follows:

- High coolant temperature

- High exhaust temperature

- High aftercooler temperature

- Crankcase pressure

- Loss of coolant flow

- Low (lubrication) oil pressure (according to the oil pressure map)

- User defined shutdown

- Air filter restriction

- Fuel filter restriction

- Oil filter restriction

- Engine oil level

- Engine overspeed histogram

- High boost

- Low boost



2 5

P a g e:

IMPLEMENTCONTROL MODULE

VIMS

3F

SERVICE TOOLCONNECTORS CAT DATA

ENGINE ELECTRONICCONTROL MODULE

(ECM)

CAT

ELECTRONIC TECCOMMUNICATION

ADAPTER

LAPTOPCOMPUTE

POWERTRAINCONTROL MODULE



2 6

P a g e:

TRANSMISSIONCONTROL ECM

ADEM I

CONTRO

SERVICELAMP

MESSAGE CENTERMODULE

GAUGE CLUSTERMODULE

KEMO

SENSORS

VIMS/VIDSINTERFACE

MODULE

VIMS ONLYINTERFACE

MODULE

SENSORS

VIMSSERVICE TOOL

ANDSOFTWARE

CAT DATA LINK

SERVICEKEYSWITCH

ACTIONLAMP

ACTIONALARM

VIMS MAIN MODULE

DISPLAY DATA LINK

VIMS

RS-232PORT

CAT DATA LINK

VITAL INFORMATION

MANAGEMENT SYSTEM(VIMS)

SPEEDOMETER/TACHOMETER

MODULE

3F

KEYPADDATA LINK

IMPLEMENTCONTROL ECM



CHAPTER : 3500B

TIMING CALIBRATION

ELECT. ENG. CONTROL

27Page:

REFERENCE EDGE TO TDC DISTANCE

REFERENCEEDGE ASSUMED

CYL. NO. 1 TDCACTUAL

CYL. NO. 1 TDC

TIMINGREFERENCE

OFFSET

MAXIMUM TIMING REFERENCE OFFSET ± 7 DEGREES

TIMING CALIBRATIONSENSOR SIGNAL

TIMINGWHEEL

± 7 °

-7° +7°

As the Speed/Timing Sensor uses the timing wheel for a timing reference, timing calibration improves

fuel injection accuracy by correcting for any slight tolerances between the crankshaft, timing gears and

timing wheel.

During calibration, the offset is saved in the ECM EEPROM (Electrically Erasable Programmable Read

Only Memory). The calibration offset range is limited to ± 7 crankshaft degrees. If the timing is out of

range, calibration is aborted. The previous value will be retained and a diagnostic message will be

logged.

The timing must be calibrated after performing the following procedures:

1. ECM replacement

2. Speed/timing sensor replacement

3. Timing wheel replacement

4. Camshaft, crankshaft or gear train replacement



CHAPTER : 3500B

E -TRIM CODE READING

ELECT. ENG. CONTROL

28Page:

PART No.

TRADE MARK

SERIAL No.

TRIM CODE SERIAL No. BAR CODE

The code identifies the discharge and timing characteristics of the injector and is programmed into the

ECM.

If the injector is replaced, the new code must be entered via ET’s calibration menu.

Old injectors are not coded, the default code 1100 must be entered.



CHAPTER : 3500B

E-TRIM FEATURE

ELECT. ENG. CONTROL

29Page:

ALL ENGINES BUILD STARTING MAY 15, 1996 HAVE THE E-TRIM FEATURE ON THEIRPERSONALITY MODULE AND INJECTORS CODED WITH AN E-TRIM CODE

THE SOFTWARE COMPENSATES FOR INJECTOR VARIATION IN TIMING AND DISCHARGE.

THE E-TRIM IS A 4 DIDGIT CODE ETCHED ON THE INJECTOR TAPPET

IF IT IS NOT POSSIBLE TO REPROGRAM AN INJECTOR CODE IMMEDIATELY THE ENGINE

WILL NOT BE SEVERELY HARMED , ALTHOUGH IT SHOULD BE REPROGRAMMED AS SOONAS POSSIBLE TO OPTIMIZE ENGINE PERFORMANCE AND PREVENT ANY LONG TERMDETRIMENTAL EFFECTS

CAT Electronic technician - CalibrationsCAT Electronic technician - Calibrations

Select Calibration

ENGINE 3508B

Pressure Sensor Calibration

Timing CalibrationInjector Code calibration

Injector 1 1100Injector 2 1100Injector 3 1100Injector 4 1100Injector 5 1100Injector 6 1100Injector 7 1100Injector 8 1100

Injector Code

Change



CHAPTER : 3500B

COLD MODE TIMING

ELECT. ENG. CONTROL

30Page:

30° C 50° C 60° C

COOLANT TEMPERATURE IN DEGREES FAHRENHEIT

LOW ENGINE SPEEDFIXED TIMING

HIGH ENGINE SPEED

TOWARMMODE

TIMINGADVANCE

BTDC

Cold Mode

The desired timing is retarded during Cold Mode operation based on coolant temperature and engine

speed.

1. For coolant temperatures at or below 86°F:

Timing will be retarded to protect the engine against high cylinder pressures. Idle is elevated to 1300

rpm (with parking brake ON and transmission in NEUTRAL).

2. For coolant temperatures above 86°F and below 140°F, the timing will advance. For engine speeds

below 1200 rpm, timing will vary according to the low engine speed line.

NOTE: Neither fuel nor engine speed is limited during Cold Mode operation. When cold mode

operation is deactivated, the desired timing returns to normal operation.



CHAPTER : 3500B

FRC OFFSET

ELECT. ENG. CONTROL

31Page:

VALID NUMBERS -25 to +25

-25 +25

LESS SMOKESLOWER RESPONSE

MORE SMOKE

FASTER RESPONSE

0AcceptableresponseClean exhaust

©1994 DenebaSystems,Inc. ©1994 DenebaSystems,Inc.

The Fuel Ratio Control has been optimized to provide excellent performance and black smoke control

without any need for adjustment. There should be no need to use the “Fuel Ratio Control Offset” except

for special circumstances.

Changing the Fuel Ratio Control Offset parameter allows the customer tailoring of the fuel to air ratio in

order to compensate for winter blend fuel, individual costumer preference etc.

Use of the Fuel Ratio Control Offset parameter will NOT affect overall power output of the engine. The

parameter should NOT be used to mask possible engine performance which may exist.



CHAPTER : 3500B

COLD START LOGIC

ELECT. ENG. CONTROL

The ECM cuts out each cylinder for a brief amount of time to see if that injec-tor is contributing to power. If not injec-

tion will be stopped to that cylinder.TheECM will retest any cutout cylinder(injector) every so often to see if it start-ed to fire or not.

HELPS REDUCE WHITE SMOKE DURING

ENGINE WARM UP

In cold mode the ECM stops injection

to non-firing injectors until the enginehas reached a certain temperature (coolanttemperature).

Sensores 3500B EUI

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Transcript of Sensores 3500B EUI