Underhood Service, February 2014

®A MAGAZINE

� ASE A1 Test Prep � DiagnosticDilemma: Stalling � DiagnosticPathfinder: Cold Treatment

Reader Service: Go to www.uhsRAPIDRESPONSE.com

CONTENTS

PublisherJim Merle email: [email protected] 330-670-1234, ext. 280

EditorAndrew Markelemail: [email protected], ext. 296

Managing Editor Chris Crowellemail: [email protected], ext. 268

Graphic Designer Dan Brennanemail: [email protected], ext. 283

Contributing Writers Gary Goms, Scott “Gonzo” Weaver, Bob Dowie and John Forro

Ad Services (Materials) Cindy Ottemail: [email protected], ext. 209

Technical Editor Larry Carley

Circulation Manager Pat Robinsonemail: [email protected], ext. 276

Subscription Services Maryellen Smithemail: [email protected], ext. 288

2 February 2014 | UnderhoodService.com

2.14Volume 19, No. 2

16Drivetrain DiagnosticsSolving Electronic Control ProblemsTroubleshooting an automatictransmission problem can be veryprofitable. Many repairs do notrequire that the transmission beremoved from the vehicle, so someproblems can be solved with just ascan tool.

®®

A Publication

16

4230

32Diagnostic DilemmasIntermittent StallDiagnosing intermittent stallingcomplaints is a challenging experi-ence for any diagnostic technician.Gary Goms shows us one casewhere it could be a problem withcommunications.

42Diagnostic PathfinderCold Weather DiagnosticsJohn Forro discusses an interest-ing no-start problem where theissue was influenced by the weath-er and trying to diagnosis theproblem inside a warm shop wasan issue.

DEPARTMENTS

6 Directions

8 Gonzo’s Toolbox

10 Aftermarket Update

20 ASE A1 Prep: Head

Gasket

22 Emissions: Platinum

Problems

26 Air Filters & Fuel Trims

46 Tech Tips

50 SHOP: New Products

53 Classifieds

52 RAPID RESPONSE

56 Emissions Update: EGR

Valves and Air Pumps

A Publication

Brent Crago, ownerTop Tech AutomotiveCleveland, Tennessee

Albert Duebber, owner Duebber’s Auto ServiceCincinnati, Ohio

Marvin Greenlee, owner Meade & Greenlee Inc.Salem, Oregon

Anthony Hurst, ownerAuto DiagnosticsEphrata, Pennsylvania

Roger Kwapich, owner Smitty’s AutomotiveToledo, Ohio

Rick O’Brien, technicianCoachworksPortland, Maine

Tom Palermo, general managerPreferred Automotive SpecialistsJenkintown, Pennsylvania

Van Pedigo, ownerRichfield Automotive CenterRichfield, Ohio

Paul Stock, owner Stock’s Underhood SpecialistsBelleville, Illinois

Michael Warner, owner Suburban WrenchPennington, New Jersey

EDITORIAL ADVISORY BOARD

UNDERHOOD SERVICE (ISSN 1079-6177)

February 2014, Volume 19, Number 2): Published monthly by Babcox, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Phone (330) 670-1234, FAX (330) 670-0874. Periodical postage paid at Akron, OH44333 and additional mailing offices. POSTMASTER: Please send address changes to UNDERHOOD SERVICE, 3550 Embassy Parkway Akron, OH 44333. UNDERHOOD SERVICE is a trademark of BabcoxMedia, Inc. registered with the U.S. Patent and Trademark Office. All rights reserved.

A limited number of complimentary subscriptions are available to individuals who meet the qualification requirements. Call (330) 670-1234, Ext. 288, to speak to a subscription services representative orFAX us at (330) 670-5335. Paid Subscriptions are available for non-qualified subscribers at the following rates: U.S.: $69 for one year. Canada: $89 for one year. Canadian rates include GST. Ohio residents add current county sales tax. Other foreign rates/via air mail: $129 for one year. Payable in advance in U.S. funds. Mail payment to UNDERHOOD SERVICE, P.O. Box 75692,Cleveland, OH 44101-4755. VISA, MasterCard or American Express accepted.

Sales Representatives: Bobbie [email protected], ext. 238

Sean [email protected], ext. 206

Dean Martin [email protected] 330-670-1234, ext. 225

Glenn [email protected] 330-670-1234, ext. 212

Jamie Lewis [email protected] 330-670-1234, ext. 266

John Zick [email protected] 949-756-8835

List Sales Manager Don [email protected], ext. 286

Classified Sales Tom [email protected], ext. 224


®®

Underhood Service is a member of and supports the following organizations:

ADVERTISING REPRESENTATIVESHOME OFFICE3550 Embassy Parkway Akron, Ohio 44333-8318330-670-1234FAX 330-670-0874www.babcox.com

PRESIDENTBill [email protected], ext. 217

VICE PRESIDENT Jeff [email protected], ext. 282

Columns

20

22

26

56

»Directions By Andrew Markel | EDITOR

Relax - R1234yf is notthe end of the world.

Iattended the Mobile AirConditioning Society’s 2014Training Event and TradeShow in New Orleans last

month. The main topic of discus-sion was R1234yf, or “twelve-thir-ty-four” in A/C lingo. There has been a lot of hypeabout the changeover to thisrefrigerant. Don’t panic. Thereality is that it is not the “airconditioning apocalypse”some are predicting. Instead,it will be a slow adoption thenext three to five years. R134awill not be phased out, but itwill be regulated and taxedheavily. The reason behind the changeis the length of time refriger-ants can linger in the upperatmosphere. R134a may takeup to 10 years to breakdowninto a non-greenhouse gas.Twenty-five years ago, this wasseen as considerable improve-ment over the 100-year-pluslifespan of R12. But R1234yf isa further advancement overR134a, as it takes only three tofour years to break down in theupper atmosphere.

You have TimeRelax, now is the time totrain and tool up. R1234yf isnot required until the 2017model year. Some models arebeing switched over now soautomakers can receive green-

house gas credits until the2016 model year.Even with the quick break-down of R1234yf, you will stillhave to purchase a newmachine to recover and recyclethe new refrigerant. You willalso need to understand thenew oil compatablity issueswith the R1234yf and whathappens when refrigerantsmix. The one investment youshould make now is a refriger-ant identifier tool.

The performance of R1234yfis very similar to R134a. Therewill be no major changes tosystem components. There arechanges to the H-block, hosesand the programming in themodule that controls theHVAC system. There are reports of some carmanufacturers not wanting touse R1234yf due to the flam-mability issue. Ignore the sto-ries about increased flammabil-

ity. They will comply soonerrather than later. The flamma-bility of R1234yf is no worsethan anything else inside theinterior, including the plasticsused in the interior. Some say the posturing is todelay the changeover until thecurrent market prices forR1234yf go down. Currentprices for the new refrigerantare around $120 a pound andtypically can only be found atnew car dealerships. The pricewill come down significantly inthe next few years as plantsaround the world ramp upproduction. If you were working in 1994at a shop when the first R134acars hit the aftermarket, charg-ing $65 for a pound of R134a orR12 was not unusual. Backthen, some shop owners madethe mistake of building stock-piles of refrigerant at the inflat-ed prices. The main issue is not with thechemical structure or politicsbehind R1234yf, it is how itwill be serviced. There will beissues with contamination assystems are serviced. Some oilswill not be compatible. You may get a vehicle in yourshop in the near future thatmight have a blend of refriger-ants. But these are issues thatcan be resolved with trainingand tools. �


Vehicles with R1234yfCadillac XTS (2013, 2014) Chevrolet Spark EV (2014)

Chrysler 300 (2014) Dodge Challenger (2014) Dodge Charger (2014)

Honda Fit EV (2013, 2014) Jeep Cherokee (2014) Range Rover (2014)

Range Rover Sport (2014)


Monday through Friday it’s the sameroutine: My average day begins withthe usual commute to work, coffeeand the turn of my key to the front

door. I unlock the overheads and do any morningpaper work I have waiting. For the most part, everyworking day has the same general routine, one dayto the next, each month and each year.

Being under the dash or hood of the modern caris my comfort zone, but it doesn’t hurt to get out ofmy comfort zone. Like a lot of people, that day-in,day-out grind can give me a snapping attitude. Icould use a reminder now and then that what I dofor a living ain’t all that bad, and I owe my cus-tomers a great deal of gratitude for their patronageand for putting up with this snarly old mechanic.You can take those average days in your own littlecomfort zone for granted and forget there is moreto what makes the world go around besides thenext car you’re working on. Sometimes it mighttake a little nudge from an outside source to getyou to realize it.

Recently, I took a few days off and ventured outon a road trip with my wife to one of her “comfortzones.” Ok, I was “volun-told” by my wife, but Ididn’t complain too much. It was three days of lit-tle old ladies, sewing machines and quilts.Goodbye, comfort zone.

I didn’t have any tools, scanners or hoods tohide under. Well over a hundred women with scis-sors, big fancy (expensive) sewing machines andcolorful fabric were on hand. There weren’t manyhusbands at the retreat, and the hotel staff had itshands full, so they kept me busy as their bell boy(minus the quirky cap of course), carrying theirmachines from the parking lot to their classrooms.If you ask my wife she’ll tell you, “Oh, he fusses,but he loves every minute of it.” I wasn’t con-cerned about what she was telling them anyway, Ijust pulled my ball cap down a bit tighter andasked the next lady with a sewing machine,“Where do ya’ want this one moved to, ma’am?”

This whole experience made me think of what itis like for a non-car person to enter an automotiverepair shop. The actual interaction with the servicewriter or mechanic can be intimidating. For me, aweekend with the wife surrounded by thread andquilts was, believe it or not, intimidating.Especially when one of them asks me somethingabout their sewing machine or quilting.

Look, I know what a PCM and a ball joint are,but I haven’t a clue about flying geese or half-square triangles. And these women loved to rub itin. Uncomfortable? Yes. Intimidating? Well, let’sput it this way: When I was stuck in front of asewing machine and clued in on which buttons topush to make it sew, they got quite a chuckle outof watching some big, burly guy fumble aroundwith a sharp needle and try to hold a thin piece offabric with his nubby fingers. Sooner or later oneof them would push me aside and say, “Here, letme show ya’ how to do this.”

I’d like to think I can learn how to operate anysort of machinery, even one of these ultra-expen-sive sewing machines, but these women are in aleague of their own. They made it look so easy, andI can’t even figure out how to sew a straight line.

I certainly can take some lessons from the quilt-ing retreat. The women did their best to make mefeel comfortable. The real heart of the intimidationwas trying to hold a conversation with them andnot having a clue what they were talking about, orwhat they were doing.

I’ve got to keep this in mind when I’m back atthe shop. I should try harder not to be so intimi-dating, work to keep things on common ground,and not make it so overwhelming for the customer,especially those who are uncomfortable about astranger they just met working on their car. I got it,ladies — thank you. Now, the other question is,can I turn some of the experience of being out ofmy comfort zone into my average day? I’m suregoing to try. �

By Scott “Gonzo” Weaver

»Gonzo’sToolbox

Lessons from a day outof my comfort zone

For free e-mail updates with the latest aftermarketnews, tech tips and supplier promotions, log onto AutoCarePro.com.

»AftermarketUpdateBrought to you by:

Federal-Mogul’s popular, free“SmartChoice™ Mobile” app forautomotive service providers hasbeen selected for the Frost & Sul-livan North American CustomerValue Leadership Award. TheFrost & Sullivan award is pre-sented annually to a companythat has demonstrated excellencein implementing strategies thatproactively create value for itscustomers. Representatives of theFederal-Mogul Vehicle Compo-nents segment received theaward Jan. 14 during the Frost &Sullivan Excellence in Best Prac-tices Awards Gala in New Or-leans.The innovative SmartChoiceMobile app enables users ofiPhone and Android devices toinstantly access the latestFederal-Mogul parts informationand technical support for virtu-ally any passenger car or lighttruck, and communicate detailedinspection findings — includingphotos and repair estimate —directly to the vehicle owner.The app includes VIN scanningtechnology that can instantlycapture critical vehicle informa-tion and link the user to all cor-responding parts and repairinformation via Federal-Mogul’swww.FMe-Cat.com applicationsdatabase.“Federal-Mogul has revolution-ized the repair sector by provid-

ing service professionals with atool that integrates the threebasic components of the repairprocess: fast, accurate identifica-tion of the vehicle application;detailed information about theparts needed for the repair; andclear, concise communicationwith the consumer,” wrote theFrost & Sullivan Best Practicesresearch team.The Frost & Sullivan team high-lighted three key characteristicsthat make SmartChoice Mobileuniquely valuable for repair pro-fessionals: Ease of use (the appfeatures a highly intuitive userinterface that minimizes thenumber of data inputs and clicksnecessary to access information);availability across multiple plat-forms; and the unparalleledbreadth of available content and


Federal-Mogul ‘SmartChoiceMobile’ App Selected for NorthAmerican Customer ValueLeadership Award

American Petroleum Institute’sMotor Oil Matters Program Calls ForConsumers’ New Year Car-Solutions

Motor Oil Matters (MOM) recently launched its “New Year’s Car-Solution” Sweepstakes, a Facebook promotion to encourage car andtruck owners to resolve to use high-quality motor oil in their vehiclesin 2014. Those who share their resolution with MOM have a chance towin a pre-paid $100 gift card.“MOM created this sweepstakes to continue the push to edu-

cate car and truck owners in a fun, interactive way about theimportance of using high-quality motor oil and its importance totheir second largest investment: their vehicle,” said Kevin Ferrick,API’s Engine Oil Licensing and Certification System manager.“Proper engine maintenance, particularly regular oil changesusing oils that meet specific performance standards, is pivotal tothe overall health of your vehicle, especially in harsh weather likemany of us are experiencing.”Consumers can enter the sweepstakes by logging on to the Motor

Oil Matters Facebook page (www.facebook.com/MotorOilMatters)and posting a comment on that day’s “New Year’s Car-Solution”Sweepstakes Facebook post. Ten lucky winners will be determinedthrough a random drawing to be held soon after the sweepstakesclose.


» AftermarketUpdate

Sammy Guinn of Guinn’s Tire & Auto in Marietta, GA., is the2013 CARQUEST ‘Ten To Win’ Sweepstakes Grand Prize Win-ner. Guinn is the winner of a fully restored 1965 Ford Mustang.He took delivery of his prize Jan. 18 at the Barrett-Jackson Auc-tion in Scottsdale, AZ.The CARQUEST Ten to Win Sweepstakes was a 10-monthcontest, held February 2013 to November 2013, exclusivelyfor professional customers of CARQUEST Auto Parts stores.Each month featured a customer winning a trip to the 2014Scottsdale Barrett-Jackson Auction and a chance to win thefully restored 1965 Ford Mustang.Grand Prize Winner Sammy Guinn is owner of Guinn’s Tire& Auto, a family-owned and operated business in theMarietta, GA., area for more than 35 years. His business isalso a proud member of TECH-NET Professional AutoService.

CARQUEST Auto PartsAnnounced ‘Ten To Win’Sweepstakes Grand Prize Winner

live technical support. Nearly5,500 industry professionals havedownloaded the app since itsintroduction in late September.“SmartChoice Mobile is a cen-tral part of the growing digitalecosystem available to profes-sional technicians who rely onany Federal-Mogul product,”said Brian Tarnacki, director,global market strategy, Federal-Mogul Vehicle Components seg-ment. “The entire automotiveparts and service industrydepends on the continued opera-tional efficiency and competitive-ness of independent service busi-nesses. This tool, like our manyother online and in-market tech-nical resources, is ultimately aninvestment in our customers’long-term success.”The vehicle service professionalcan use the app’s “SendInspection Results” feature tocompose and send to the con-sumer a shop-branded email,complete with inspection results,repair estimate and images of thevehicle’s worn parts. This emailsummary also includes instant-reply and callback buttons toencourage the vehicle owner toask questions and/or authorizethe repair. Technicians can alsouse the app to connect with anASE-certified technical specialistat the Federal-Mogul TechnicalEducationCenter (F-M TEC) inSt. Louis.The free Federal-MogulSmartChoice Mobile app can bedownloaded through the AppleApp Store and Google Play aswell as the company’swww.SmartChoiceApp.comwebsite.


» AftermarketUpdate

xx

The Alliance of AutomobileManufacturers (Alliance), theAssociation of GlobalAutomakers (Global), theAutomotive AftermarketIndustry Association (AAIA)and the Coalition forAutomotive Repair Equality(CARE) have announced theircollective acceptance of anational agreement to ensureconsumer choice in post-war-ranty auto repair, decisivelyending the longstanding “Rightto Repair” debate within theindustry.

The national agreement isbased on a recent law finalizedin the Commonwealth ofMassachusetts (Chapter 165 ofthe Acts of 2013). The signedMemorandum ofUnderstanding (MOU) extendsnationwide the essential provi-sions for all light vehicles nego-tiated in the Massachusetts law;it impacts all companies andorganizations that are currentlymembers of the signatory asso-ciations.This national agreementensures the Alliance, Global,

AAIA and CARE will standdown in their fight on “Right toRepair” and work collectivelyto actively oppose individualstate legislation while therespective groups work toimplement this MOU. In themeantime, the parties agreethat further state legislation isnot needed and could serve toweaken the effectiveness andclarity of the MOU.“We are excited that consumersand independent repair facilitiesaround the nation will have thesame access to the information,tools and software needed toservice late-model computer con-trolled vehicles as is requiredunder the Massachusetts right torepair statute,” said KathleenSchmatz, president and CEO ofthe Automotive AftermarketIndustry Association. “Webelieve that the resulting compet-itive repair market is a win-winfor car companies, the independ-ent repair industry and, mostimportantly, consumers.”“Automakers manufacturehigh-quality, innovative vehi-cles that provide strong value,safety and convenience to ourcustomers,” said MitchBainwol, president and CEO ofthe Alliance of AutomobileManufacturers. “Accessible,efficient, accurate and competi-tively priced repair and serviceare paramount, and franchiseddealers and the aftermarketplay unique and importantroles in the repair process.” �

Automakers, Aftermarket To PreserveConsumer Choice In Auto Repair


Troubleshooting an automatictransmission can be one ofthe most intimating diagnos-tic procedures at a shop. The

first reaction is typically, “We don’t dothat type of work.” But there is profitin performing drivetrain diagnosticsand “in-the-car” repairs. The modern automatic transmis-

sion and attached drivetrain hasmany “mechatronic” parts that controland protect the traditional clutches andplanetary gears. These devices shift thegears, lock the clutches and regulate the fluidpressures. Most of these items can be diagnosedand replaced while the transmission is still inthe vehicle.

Tool UpSpecial tools are often needed when diagnosing

transmission problems and when overhaulingunits. In days gone by when transmissions wherepurely mechanical and hydraulic, all you neededwas a set of high-pressure gauges to check linepressures. You also needed a vacuum gauge tocheck the engine’s intake vacuum and the integri-

ty of the vacuum modulator. But withtoday’s electronic controls, you

need a scan tool, scope and amultimeter.

Transmission codes and sensor data on late-model vehicles is accessed through the OBD IIdiagnostic connector and the Powertrain ControlModule (PCM) diagnostic gateway module. Buton some vehicles, the information is often foundin a separate Transmission Control Module (TCM)or Body Control Module (BCM). Either way,you’ll need a scan tool to access fault codes andoperating data.A scan tool can also help you check for commu-

nication faults between the PCM and transmis-sion controller if the vehicle has separate comput-ers. Problems here will typically cause the trans-mission to go into a “limp in” mode that may lockit in 2nd gear.Some transmission problems may or may not

set a fault code and turn on the MIL lamp, so it’simportant to always scan the PCM or transmis-sion module for codes if there’s a transmission-related complaint or driveability issue. Someengine sensor failures (for example, the throttleposition sensor, MAP sensor or vehicle speedsensor) can also affect the operation of the trans-mission. So, it may be necessary to also checkthese sensors.

»DrivetrainDiagnostics By Andrew Markel | EDITOR

In-the-Car Diagnostics: SOLVING TRANSMISSION ELECTRONIC CONTROL PROBLEMS


» DrivetrainDiagnostics


If you find atransmissionfault code, youmay have tocheck the resist-ance of a sole-noid in the valvebody, its operat-ing voltage orthe frequency ofits control signalfrom the computer. Thiswill require adigital multime-ter (DMM) thatcan read voltage,resistance and frequency ordwell.You’ll also

need the appli-cable serviceinformation that includes wiring schematics andOEM diagnostic charts with test specifications forall the components that need to be checked. Thiskind of information can be found in OEM servicemanuals, on OEM websites (daily one-time accessfees are typically $15 to $25), or through online tech-nical information service providers. You should alsocheck for any technical service bulletins (TSBs) thatmay be related to the transmission problem. Insome cases, it may be necessary to reflash (repro-gram) the PCM or transmission module to cure aparticular fault.

Diagnostic Strategies and TransmissionsWhen using a scan tool to diagnosis a drivetrain

problem, it’s often what is not displayed on the scantool that will lead you to your final diagnosis. Themodern transmission is one of the most connectedcomponents on a vehicle. If a PCM or TCM can’t seeinputs like engine speed, load or throttle position, itwill assume the worst and put the transmission intoa safe or limp mode.The transmission does not have discreet sensors

connected to the throttle body, crankshaft or intakemanifold. Instead, the transmission shares informa-

tion with the engine control and other modules inthe vehicle using a serial data bus. Most vehiclesmanufactured after 2004 put the TCM or PCMmodule on the hi-speed, two-wire CAN networkalong with BCM and ABS modules. The topology for these networks is typically a loop.

If a module is not operating, the existing modulescan still communicate on the bus. When you’re usingyour scan tool to solve a transmission problem, youmay have to look at the PIDs or datastream from theECM or BCM to see what modules are talking on thebus. If you can’t communicate with a transmission con-

trol module with your scan tool, look for transmis-sion information in the connected modules. TheBCM will monitor information from the TCM ongear position so it can tell the instrument clusterwhat gear to display for the driver. It can also work the other way. If a TCM is not able

to communicate with the ECM, looking at the trans-mission-related PIDs for calculated engine load,throttle position and manifold air pressure mayshow that the ECM is not communicating on the net-work or has other issues.

THINKING OUTSIDE THE CASE: Three Causes of Transmission Complaints

Non-Transmission SensorsCausing Transmission ProblemsMost transmission control modules useinputs from other sensors on the vehicle. If avehicle can’t accurately calculate the load onthe engine, it will adjust the line pressure andslippage to the inaccurate calculation. Thiscan damage the transmission. Sensors used to calculate the load caninclude the Mass Airflow Sensor (MAF),Throttle Position Sensor (TPS) and ManifoldAir Pressure (MAP). If unmetered air is enter-ing the cylinder through a leak, the engineload will be below the actual percentage. Thiscan cause the module to use different shiftpoints and line pressures. This could causethe transmission to delay shifts, overheat andpossibly burn the fluid. Maintenance items like a restrictive air filter,dirty air flow meter or blocked crank case ven-tilation system can change the calculatedengine load to the point where it can influenceshift points and shift quality.

Wiring Harness ProblemsThe wiring harness and connectors on mosttransmissions operate in a unique environ-ment. Normal automatic transmission fluid’sconductivity is very low. Hybrids usually havea specification for a fluid that is non-conduc-tive. In most cases, the fluid will not damageor short the connections; the detergents andchemicals will cause the degradation of thematerials in the wiring harness that might beoutside of the case. Also, check for any damaged wires and con-

nections that could be damaged by impactwith road debris, weak or shifting motormounts and hot exhaust systems.

GroundsSince the mid 1990s, the grounds for sole-noids and sensors have changed dramatically.Never assume the chassis ground is comingthrough the case or valve body. Study thewiring diagrams before trying to diagnose adead or open solenoid. Some transmissionscan have multiple ground points for the sole-noids, module and sensors. �



Passing the ASE A1 canbe difficult. Do not gointo this test with thenotion that this is an

exam for engine rebuilders.Many of the tasks in the A1 tasklist are required every day at ageneral repair shop for top-endengine repairs.

From the ASE A1 TaskList: A1 #17: Inspect cylinder head

mating surface condition andfinish, reassemble and installgasket(s) and cylinder head(s);replace/torque bolts accordingto manufacturers’ procedures.

Surface FinishThe level of surface finish isdetermined not only by theengine materials, but also thegasket type. The aluminumcylinder head surface shouldbe resurfaced to the cylinderhead gasket manufacturer’sspecifications. In short, thehead gasket surface shouldappear polished rather thanrough, with composite gas-kets requiring a finish of nomore than 45 roughnessaverage (RA). The rougherthe surface on an aluminumcylinder head, the shorter thecylinder head gasket life. Butcheck the service informationand the recommendationfrom the gasket’s manufac-turer for the recommendedsurface finish.

Inspection and CleaningAny debris that’s snaggedand drug across the metal bythe milling head may mar themating surface. Clean baremetal is all you want to see fol-lowing the initial cleaningprocess. Checking for cracks incast iron heads requires a cleansurface for the magnetic parti-cle detection powder. Likewise,checking aluminum castingsfor hairline cracks with pene-trating dye also requires aclean surface. Even porosityleaks in aluminum heads andblocks may be masked ifthere’s a heavy layer of gunkon the metal.

Failures and CracksThe vulnerability of alu-minum-head engines to headgasket failure is caused by thealuminum cylinder head

expandingapproximately 1.5 timesmore than the cast-iron block.Although measured in thou-sandths of an inch, this smalland seemingly insignificantdifference between the expan-sion rates of aluminum andcast iron will eventually wearout the head gasket and causefailure.Cracks typically form whena cylinder head undergoestoo much thermal stress. Lossof coolant, severe overheat-ing as well as suddenchanges in operating temper-ature from hot to cold can allcreate the kind of conditionsthat cause cracks to form.Cracks do not necessarilymean a cylinder head has to bereplaced. Many cracked heads

»ASE A1 TestPrep

Cylinder Heads and Gaskets

once thought to be beyond repair are now beingfixed by skilled machine shops

Do Not Reuse BoltsBolt breakage and uneven gasket loading or loss oftorque can cause a newly installed head gasket toleak. TTY head bolts are designed for one-time usebecause they stretch permanently once they aretorqued down. This helps even out the clampingforce of the cylinder head on the head gasket.

Head Bolt InstallationDirty or damaged threads

can give false torque read-ings as well as decrease abolt’s clamping force by asmuch as 50%. Wire brush allbolt threads, carefully inspecteach one, and replace any thatare nicked, deformed or worn. Ifa bolt doesn’t thread into a holesmoothly with finger force alone,there is a problem.Dirty or deformed hole threads in

the engine block can also reduceclamping force. Run a bottoming tapdown each bolt hole in the block. Thetops of the holes should also be cham-fered so the uppermost threads won’tpull above the deck surface when thebolts are tightened.Make sure the washers are positioned

with their rounded or chamfered side up, and thatthere is no debris or burrs under the washers.Anaerobic sealant might be required for some headbolts that are exposed to the coolant in the waterjacket. When using these products, make sure theyare applied to the correct area of the bolt. Anaerobicsealers cure without the presence of air and havespecific procedures when it comes to application,torque and cure times. Always look up the specified tightening sequenceand recommended head bolt torque values for anengine before installing the head gasket, and use anaccurate torque wrench to tighten standard-typehead bolts in three to five incremental steps follow-ing the recommended sequence and torque specs forthe application. �

» ASETestPrep

Go to www.uhsRAPIDRESPONSE.com


News broke during production of thisissue that platinum miners in SouthAfrica went on strike. This stoppage inplatinum mining carries a butterfly ef-

fect potential for the U.S. aftermarket. Vehicles cannot meet today’s environmentalstandards without precious metals. Platinum isone of the key catalyzing, emissions-reducing ele-ments within a catalytic converter. An averagecatalytic converter contains several hundred dol-lars worth of platinum, palladium and rhodium.A butterfly effect in chaos theory refers to how asmall change in one place can result in large dif-ferences down the road in a different time or dis-tant place. A labor issue in another country is nosmall issue, but that situation half a world awaycould have real impact on the price, sales andsafety of catalytic converters.

Labor unrest backgroundAccording to reports, around 70,000 employeesfrom the world’s three biggest platinum produc-ers — Anglo American Platinum, ImpalaPlatinum and Lonmin Platinum — are participat-ing in the strike. The mines employing those70,000 workers are said to contribute 70 to 80percent of the world’s platinum. A strike of thissize will mean a shortage of 9,000 ounces per day. As of press time, the government was attempt-ing to mediate the labor dispute.

The price of platinumStoppages in production occurred at randomtimes starting in November 2013, enough to dropproduction 5 percent from the previous year. Thisunrest, prior to the actual strike, already movedthe platinum price needle. The metal’s priceclimbed about 12 percent in the previous monthand six percent during a two-month period. Again, even without knowing how the strikeplays out, estimates already show platinum pricesto average $1,632/oz. in 2014 and $1,750/oz. in2015. The price was sitting near $1,480/oz. atpress time. In 2011, the post-financial-crisis priceof platinum hit its peak of $1,901/oz.

Converter theft deterrentsAs the price of platinum goes on the rise, so towill the rate of catalytic converter thefts, especial-ly for trucks and SUVs. The thefts are already hitting the news inRoseville, Calif. One inventive truck owner suc-cessfully thwarted a potential theft by welding apiece of metal rebar across his catalytic converter.Resourceful muffler shops in that area are said tobe offering a rebar-welding service for a fee.For the those without rebar or a welder, there areproducts on the market that offer similar protection:• The CatStrap takes advantage of the built-inheat shields in most catalytic converters by rout-ing the strap beneaththe shield. If a thiefattempts to saw freea catalytic converter,the CatStrapresponds with a 125decibel alarm andhardened steel pinsthat will actuallymelt the teeth of the saw blade.• The CatClamp is installed by placing the splitclamp assemblies in place before and after theconverter. A cable is then routed through bothsplit clamps and around or through the chassisand back through both split clamps.Another potential converter crime preventionmeasure is etching a vehicle’s license plate num-ber into the converter. The Sacramento Bee articleabout therebarcrimestoppernoted thatfour automotive service shops in the Roseville,Calif., area offer free catalytic converter etchingsby appointment. If catalytic converter thefts start to uptick andmake the news in your area, you might considerbrushing up on your etching skills or considerselling theft deterrent products. �

»EmissionsUpdate By Chris Crowell | Managing Editor

STRIKE IN SOUTH AFRICA COULD HAVE CONSEQUENCES FOR CATALYTIC CONVERTERS


The modern enginemeasures twothings extremelywell, the

amount of air goinginto the combustionchamber with themass airflow sensor(MAF), and thebyproducts that aregenerated by the combustion event withthe oxygen sensor. Thesemeasurements allow the engine’scomputer to put the right amount of fuel and sparkinto the cylinder to give the most efficient and cleanestcombustion event.Carburetors are stuck with a limited range of fuel

trim due to fixed jets. In order to get a cold engine tostart, a carburetor would block off the air to a ven-turi with a choke. The fuel mix would be richer, andthe engine could start. The same phenomenon hap-pens on fuel-injected engines with dirty air filters. But fuel-injected engines are able to compensate by

changing fuel trim. Since there is less oxygen, theengine will need less fuel. Less fuel means a leanerfuel trim and less power. This adjustment comes atthe detriment of performance by taking away fuel.It also works in the opposite direction. If unmetered

air makes its way past the MAF sensor, the oxygensensor will detect a lean combustion event. The ECMwill then instruct the injectors to pulse for a longerperiod of time. This increases fuel consumption anddecreases fuel economy.The ECM can only compensate so long before it

becomes unbalanced and can no longer add orrestrict fuel to achieve a proper oxygen senor read-ing. This is when codes are set for a too rich or toolean fuel trim. A restrictive air filter may not set acode, but the restriction and compromised fuel trimwill hurt the power and efficiency. Replacing the filter and resetting the fuel trims may return the system to normal.

What are FuelTrims?Fuel trim is the

adjustment the enginecomputer makes to thefuel mixture to main-tain a balanced air/fuelratio. Fuel trim is usually displayed as a percentage readingon a scan tool.A rich fuel mixture can produce more power (up to

a point), but it also increases fuel consumption andemissions. Conversely, a lean fuel mixture reducesfuel consumption but can also increase emissions ifthe mixture is so lean that it fails to ignite and causeslean misfire.Accurate fuel trim values require an accurate feed-

back signal from the oxygen sensor, otherwise theengine computer has no way of knowing whetherthe fuel mixture is running rich or lean. When theengine is shut off, the fuel trim values are retained inthe computer’s memory so the next time the vehicleis driven it can pick up where it left off. Erasing thecomputer’s memory with a scan tool or by discon-necting the battery or the PCM power supply to clearcodes also wipes the fuel trim values, which meansthe computer has to start learning the fuel adjust-ments all over again the next time the engine runs.

» Filters By Andrew Markel

Air Filter Fuel TrimDiagnostics

» FiltersHow to Read Fuel TrimThe engine must be started and

running to read the fuel triminformation. Choose the optionthat allows you to read systemlive data, which varies dependingon the scan tool. This will displaya long list of sensor outputs andother readings called PIDs(Parameter IDs). There will betwo fuel trim values:Short-Term Fuel Trim (STFT)

values change rapidly and canbounce around quite a bitdepending on engine load, speed,temperature and other operatingconditions. Values normally rangefrom -10% to +10%, though thereadings may jump as much as25% or more in either direction.Long-Term Fuel Trim (LTFT) is

a longer-term average of what theengine computer has been doing

to balance the fuel mixture over apredetermined interval of time.This value is a more accurateindicator of how the fuel mixtureis being corrected to compensatefor changes in the air/fuel ratiothat are occurring inside theengine.

Understanding Air Filtersand Fuel TrimsIf a filter is clogged or restrictive,

it will show a negative fuel trimvalue, which means the enginecomputer is subtracting fuel —decreasing the pulse width or on-time of the fuel injectors — toreduce the amount of fuel injectedinto the engine. This is done tolean out the fuel mixture to com-pensate for what it perceives as arich running or choked condition.Positive fuel trim air filter diag-

nostics are a little more complicat-ed. If an air filter or air inductionsystem is delivering more thanthe normal amount of air, it willcause the oxygen sensor to detecta lean condition. It will add morefuel and cause the fuel trim to bepositive. Some possible factors:

1. Collapsed Filter: This couldbe caused by a clogged wet filterthat has become damaged,ripped or dislodged by the vacu-um generated by the engine. Itwill typically flow better than aclean filter.2. Blocked MAF Sensor: If a fil-

ter is made of low quality materi-als, pieces of the filter media canbe dislodged and block the MAFsensor. They can even damagehotwire MAF sensors.

3. Damage to Air FilterHousing: If an air filter housing isdamaged, cracked or cannot cre-ate a seal around the filter, the airmay create turbulence or allowunmetered and unfiltered air toget past the MAF sensor. 4. Bad Filter Design: A lot of

engineering goes into an air filter.Base fuel trims are calculatedusing a stock filter. If a replace-ment filter used the wrong mate-rials, pleat design or gasket mate-rial, it can influence fuel trims. �



This Month's Diagnostic Dilemma: 1999Dodge Dakota, 5.2-liter engine, auto-matic transmission, four-wheeldrive, 250,000 miles.

Complaint: Engine intermit-tently stalls after 20-30 min-utes of driving time. Nodiagnostic trouble codesrecovered. Client shopreports that engine ran-domly loses ignition andfuel injector pulse andoccasionally loses com-munication with thescan tool. Black tapecovers the “checkengine” and “ABS”lights. Diagnosing intermittent stallingcomplaints is a challenging experiencefor any diagnostic technician because anynumber of electrical and mechanical failurescan cause an engine to intermittently stall.Most of us immediately narrow this laundrylist of potential failures down to the mostcommon few, which include components likethe crankshaft position sensor and electricfuel pump. In this case, my client shop had replaced thefuel pump earlier because it consistentlyfailed to produce fuel pressure. After replac-ing the fuel pump, the Dakota developed anintermittent stalling complaint that wouldoccur after about 20-30 minutes of drivingtime. Since late summer is the busy part ofthe season in our area, the client shop calledme to help locate the source of the intermit-tent stalling complaint.

The Common ElementsLet's form a strategy for solving this month'sDiagnostic Dilemma by analyzing the variouselements of the case. 1) The stalling complaint was intermittent; 2) The stall required at least 20-30 minutesof drive time before it would occur; 3) The ignition coils and fuel injectors wouldfail to pulse when the stall occurred; and 4) The scan tool would occasionally lose communication.

The constant in this case was the 20-30 min-utes of driving time required to cause the fail-ure. This is always a major clue because com-ponents like distributor pick-ups, ignitionmodules, power train control modules(PCMs) and crankshaft position sensors often

»DiagnosticDilemmas By Gary Goms

11999999 Dodge Dakota Intermittent Stall

UnderhoodService.com 33

require that amount of time to reach operatingtemperature. Next, the ignition coil and fuel injectors werelosing pulse, which might indicate crankshaftposition sensor failure. Lastly, the shop's scan

tool losing communication with the PCM wasan issue, which could also be caused by afaulty diagnostic link connector (DLC)cable or scan tool. So that was not anissue at this time.

To determine the commonelements of a case, I printedan engine performance electri-cal schematic. In many cases, Itape multiple pages togetherto help trace various circuits.This helps familiarize me with

the basic circuitry and to makemy own highlights and notationson the operation of various cir-cuits. These annotated schematicsalso provide a quick reference for

pin-testing the PCM and the Power DistributionCenter (PDC). Since it powers the ignition and injector circuits,the auto shut down (ASD) relay deserves particu-lar attention. According to the schematic, the pri-mary side of the ASD relay is powered from theignition switch through a junction blockequipped with a 10-amp fuse. Current flows fromthe junction box to the ASD relay’s primary sole-noid coil. When the ignition is turned on, thePCM is activated through the key-on circuit, asare the ASD and fuel pump relay primary, igni-tion coil and fuel injector circuits. But the ASDrelay operates only when its primary circuit ispulled to ground by the PCM. Obviously, theASD relay circuit is a primary suspect in thisintermittent stalling complaint.

Unraveling the DataWe've all heard about making decisions “in thefog of war.” The same can be said of makingdecisions “in the fog of diagnosis” because, while

» DiagnosticDilemmas

11999999 Dodge Dakota

Issues like the aftermarket relay located at the upper right-hand corner of the photo raised somequestions when diagnosing the intermittent stalling complaint on this venerable 5.2L Dodge Dakota.


we have some of the facts, wedon't have all of the facts. Myimmediate diagnostic strategywas to collect the rest of thefacts by connecting my ownscan tool to evaluate the inter-mittent no-communicationproblem and to collect codesand data. The codes included aP0443 evaporative failure code,which was irrelevant to ourstalling problem. Next was amore significant P1678 DTC,indicating, according to thescan tool, that the mechanicalinstrument cluster wasn'treceiving bus communicationmessages. Polling the variouson-board modules indicated aglaring “Body Module Fault” inthe body control module and anumber of two-digit flash codesin the ABS module.

OK, we know we're losing theASD relay and now we havesome very relevant bus commu-nications DTCS.

Diagnostic ScenariosThe ABS module had beenreplaced with a used modulethat might not fit this particularVIN. Although the ABS fusehad been removed because theABS pump wouldn’t deactivate,the module was evidently stillactive on the bus communica-tions circuit. Perhaps the ABSmodule was pulling down thebus circuit, perhaps not. But abus communications problemdoesn’t adequately explain themalfunction in the ASD relaycircuit. Nevertheless, when Ientered Chrysler’s bi-direction-al Automatic Test Mode (ATM)


This photo illustrates how I use electrical schematics. Critical circuitpins are highlighted in yellow and annotated in red. Working froma schematic is the quickest way to cut your diagnostic time.



to diagnose the instrument cluster, all thegauges activated when commanded.My next step was to install a relay circuittester attachment under the ASD relay,which allowed me to test the relay’s pri-mary power, ground and B+ output to theignition coil and fuel injectors. At thattime, I noticed that the primary for anaftermarket relay had been spliced into thepower distribution center (PDC) wiring.Next, I connected a fuel pump pressuretester so I could keep an eye on the fuelpump and pump relay activity.

Back to the Scan ToolWith my underhood diagnostics in place,it was time to start the engine and recordscan tool data. Sure enough, after about 30 min-utes of run time, the engine stalled. The fuelpressure gauge indicated specified pressure, so Itested the ASD test jumper attachment to see ifthe PCM was pulling the primary circuit to

ground. With B+ voltage present at both primaryterminals, it was obvious that the PCM wasn’tpulling the ASD primary circuit to ground duringcranking.Then my scan tool lost communication. More

ominously, a bright green “nobus” message appeared in theodometer display. A quickpolling of all modules indicatedthat all modules were reportingexcept the PCM.Quickly, I disconnected the scantool from the DLC and tested theNo. 16 port for B+ (present), No. 4port for ground (present, using atest light), No. 5 port for ground(present, using a test light) and,most important, the No. 3 andNo. 11 ports for the presence ofthe required +2.5, -2.5 voltage atthe Chrysler Collision Detection(CCD) bus communications signalports (not present). The systemwas behaving erratically and thevalues were changing very quick-ly, so I didn't check for activity atthe serial command interface(SCI) ports, which allows the scantool to communicate with thePCM and the transmission control


Connecting a fuel pressure gauge is a simple way tosimultaneously monitor the fuel pump relay and fuelpump activity.

module (TCM) where applicable. The No. 2 port isthe programmable communications interface (PCI),which allows communication with the body control module (BCM) where applicable. Also apparent was the intermittent lack of fuellevel, coolant temperature and oil pressure gaugeactivity on the instrument panel (IP). Going backto our schematics, it's important to note that allthree gauges report directly to the PCM and fromthe PCM to the instrument cluster. Since the PCM was evidently not reporting to

the scan tool or to the instrument panel, a quickcheck for power and ground was in order. Usinga test light with a No. 194 bulb, I verified theavailability of No. 2 key-on and No. 22 fused B+voltages as well as the integrity of the two redun-dant PCM grounds (No. 31 and No. 32). Next, testing directly at the No. 3 ASD relay pinyielded full battery voltage, which indicated thatthe PCM was not grounding the No. 3 pin duringcranking. At this point, I used a non-contact pyrom-eter to verify that the PCM had reached about 110°F operating temperature, which is normal for thisvintage of Chrysler PCM.

Conclusions1) The PCM was the only module lacking com-munications; 2) The IP was not receiving fuel, oil and coolantmessages from the PCM;3) The PCM was not commanding the ASD relayclosed by grounding the ASD relay primary circuit;4) No voltage was present at the No. 3 and No. 11CCD bus terminals located in the DLC; and



This “no bus” message at the odometer display indicates a bus communications failure in theDodge Dakota's CCD bus network.


5) The PCM had key-on andB+ voltages as well as redun-dant grounds. All of the diagnostic arrowswere pointing at a failed PCM.While the failure of the PCM’sASD driver was the root cause ofthe stalling complaint, the failureof the CCD bus system producedthe most apparent and visiblesymptoms of a failing PCM. Asevents developed, it was appar-ent that the CCD signal wasbeing intermittently lost at thePCM. With that in mind, the keyto solving this month’s DiagnosticDilemma is understanding thebasics of the CCD bus communi-cations system.Chrysler’s CCD bus is one ofthe most comprehensive sys-tems introduced during the1990s. To clarify, the term “col-lision detection” has to do withhow the system separates busmessages being sent by variousmodules. From a more globalperspective, it’s important tobegin mastering the basics of

bus communications. Currently,all vehicles sold in the UnitedStates since 2008 use the high-speed Controller Area Network(CAN) protocol to network on-board modules and to prioritizetheir messages. Bus communications is a com-plex subject and there are a num-ber of excellent training DVDsavailable that provide detailedinformation on how bus commu-nication and CAN systems oper-ate. Since each bus communica-tion and CAN system is config-ured differently for a wide rangeof applications, I recommendmoving from basic to complex inthe learning process. Serviceinformation can be very sketchyon some early applications, butmost of the service data on cur-rent CAN applications are generally very complete. With that, I close the book onthis case study of the '99 DodgeDakota with an intermittentengine stalling complaint. �

Testing for adequate key-on and B+ powers and redundantgrounds at the PCM is a must for analyzing any suspected PCMfailure.


»DiagnosticPathfinder By John Forro

Iusually like to see a problem first hand a halfdozen times before I feel comfortable callingit a silver bullet. However, I have seen thissame problem occur three times now this

winter season, and I think I have found the issue.Silver bullets can be a real time saver. Often Iam asked when a new Silver Bullet Book(www.johnforro.com) will be made available. Ihave found over the last several years that vehi-cles are simply made better and are not havingas many pattern failures as they once did. Sure,there are still some, like various vacuum leaks,but nowhere near as many as we once had.

No Crank, No StartThe subject vehicles were 2002-2006 Ford trucks— the first was a 2002 Ford F-150 with a 5.4 liter,second was a 2006 Lincoln Navigator with a 4.6liter and finally a 2004 Ford F-250 with a 5.4 literengine. All of the customer complaints with thesevehicles were the same: “The vehicle will notcrank/start when cold.” One customer added thatit would be fine if it was kept in the garageovernight, and one handy guy said if he jumpedthe starter it would be fine. These three vehicleswere not at my shop all at once, but over a periodof approximately 6-7 weeks.

For this article I will discuss the first vehicle,the 2002 Ford F-150, in detail. The other vehicleshad similar diagnostic processes. The customerwanted to have the vehicle towed in to my shopbecause it was having trouble starting. Somemornings it would start while others it wouldnot. This person was not a regular customer ofmine and was recommended to me by a daugh-ter-in-law. After providing the address to havethe vehicle towed in, I tried to rapidly finish upthe vehicles I was currently working on to makeroom in the shop so the tow truck could justdrop the vehicle inside upon arrival (big mis-take). I normally try to do this when possiblebecause it is difficult for me, as a one-man facili-ty, to get the dead vehicle in by myself.

First TryThe vehicle shows up about anhour later and is dropped offinside the shop as I had planned.The vehicle sat inside my shop at58 degrees while I proceeded tofinish up another vehicle I wasworking on. After another halfhour I turned my attention to theF-150. I wrote up the vehicle,tried cranking with no luck, but Inoticed the security light flash-ing rapidly.


Cold Weather Diagnostics:When the Temperature Goes Down, So Can Some Modules.

» DiagnosticPathfinder

This warranted a scan of the security system aswell as all the other modules for codes. No codesfrom any of the modules were found.At this point I thought I had a PATS (passive anti-theft system) issue, but I decided to take a visualinspection both under the hood by the ECM andunder the dash by the ignition switch areas for anypotential obvious wiring conditions. Everythinglooked up to par in both areas. I even went as faras unplugging the ECM and looked at the termi-nals both inside the ECM and the harness side ofthe connectors. Once I went back inside the vehicle, the problemwas gone! The truck cranked and started with noissue several times.At this point I considered everything I did wrongthus far. I shouldn’t have disturbed anything. Ishould have looked over a schematic and per-formed some specific circuit testing at the variousECM and ignition switch circuits. I would nowhave to wait to see if the problem would comeback. Wasted time.

I left the vehicle in the shop overnight, and inthe morning it started without any problem. Iparked the vehicle outside and throughout theday it started without any issues. I had no choicebut to call the customer and give the vehicle backwithout figuring out the problem or making anymoney.


Second TryAbout a week later the phone rings again and, aswe all already know, the vehicle was once againnot cranking and was getting towed back in. Mymind started racing to formulate an attack plan.What will I test first? What did I do last time tomake the problem disappear? Are there any simi-larities between this day and the last day that itwould not start?The only similarity between bothdays was that the temperatureoutside was very cold. Much likethe entire country, it has been anunusually cold winter here inOhio. This time I had the towtruck place the vehicle outside.Once the vehicle arrived I madesure the problem was present —no crank and security light flash-ing. I scanned for any relatedtrouble codes again, and this timeI pulled a code indicating it wasunable to communicate with theECM.

Cold Car, Hot ECMI quickly printed a schematic tocheck the ECM’s power andgrounds and, upon verifying theywere present, I removed the ECMand brought it inside the warmshop. After an hour or so I tookthe ECM back outside andinstalled it into the truck and thevehicle started right up.I was on to something. Could Ihave a bad circuit board inside thePCM, or is it a mating problem atone of the ECM connectorsbecause I disturbed them bothtimes to get the vehicle started? Ilet the vehicle sit outside longer toallow the problem to reoccur. Thistime, I took my heat gun outsideand applied heat to the ECM for acouple of minutes. After a littleheat, the vehicle started. This con-firmed my suspicion of a badboard inside the ECM. I probably

would have been able to figure this out the firsttime around if I didn’t drop the vehicle inside theshop.A new PCM, with an installed flash and program-ming the keys, repaired the vehicle. Both of theother vehicles mentioned earlier were repairedwith the same procedures. Looking at the upcom-ing forecast, we may have more of these vehiclesshowing up in the near future. �


» DiagnosticPathfinder

» TechTipsThis month is sponsored by:


GMC Sierra: Has No-Crank/No-Start Condition

Vehicle: 2009 GMC Sierra1500 SLE 5.3L, V8, MFI,OHV, VIN 0, Eng Desg LMG

Customer ConcernThe battery was jump-startedwith the key on, which resultedin a no-crank, no-start condi-tion. Theft deterrent module(TDM) DTC B3060 is present.

The module will perform the relearn, work properly threetimes, then go back into the failure mode.

Tests:1. Verify battery voltage onthe red/white wire at pin 1.2. Verify switch voltage onthe yellow wire at pin 2.

3. Verify a good ground onthe black/white wire at pin 3.4. Verify communications onthe dark green wire at pin 4.5. If OK, replace and programthe TDM.Courtesy of Identifix’s “Five Fast

Fixes”

The 1998 Jimmy-Blazer Fuel Tank DilemmaThe Chevrolet Blazer and GMC Jimmy are popularGM vehicles, and in 1998 they were equipped with anumber of vehicle options that make determining thecorrect fuel module for either application confusing.These vehicle applications could potentially offerthree different fuel modules to fit. They areFG0072, FG0052 and FG0071.The FG0072 fuel module is designed for use ontwo-door applications. This is easy to identify, sothere is little confusion regarding these applications.The confusion typically surrounds the remainingtwo fuel modules, FG0052 and FG0071, whichboth fit four-door applications.The catalog indicates that FG0052 fits the four-door Blazer with an 18-gallon fuel tank, whileFG0071 fits a four-door Blazer exc. 18-gallon fueltank. Regardless of the descriptions, mistakes canbe made when fuel tank size cannot be determined.If you are having difficulty determining the tanksize, see if the tank is made of plastic or steel. The18-gallon tank option is made of plastic, usingFG0052. The exc. 18-gallon tank option is made ofsteel, using FG0071.If you do not know either the fuel tank size ormaterial, you can determine the correct module byexamining it once removed from the fuel tank.The FG0052 fuel module, which is used in the 18-gallon plastic tank, uses a cuff-style seal and coverdesign as shown in the photo.By spending minimal time determining the type

of fuel tank and/or module used in these applica-tions, you can reduce part returns and increasecustomer satisfaction. Courtesy of Delphi.

This is the seal and cover design used on theFG0071 fuel module. This design was made foruse in a steel fuel tank.

This is the seal and cover design used on theFG0052 fuel module. This design was made foruse in a plastic fuel tank.


Models: •1997-2010 GM passenger cars and light dutytrucks, including Saturn•2010 and prior HUMMER H2, H3•2005-2009 Saab 9-7XAn analysis of returnedpower steering (PS) pumpsthat had been replaced fornoise, no power assist, noor low pressure and leakingconditions has indicated ahigh number of "No Trouble Found" results.When attempting to repaira power steering concern,the steering system analyzer should be used toassist the technician in asuccessful diagnosis. TheSaturn ASTRA, however, does not use the PowerSteering System Analyzer.

In addition, extensive warranty analysishas shown that the following situationsare all significant root causes of PS pumpfailures:• Improper pulley installation• Re-using the O-rings• Using fluid other than the OE-specified steeringfluid• Failure to flush the PS system

GM recommends the following tips forreplacing a PS pump:1. Low or no pressure from the PS pump may bethe result of dirty or contaminated fluid, which

could cause the pressure relief valve to stopfunctioning. Using the proper tools, flushand bleed the PS system. Any residual con-taminants will result in pump failure.2.When removing the pulley, use theproper special tools. Because the pulleyalignment is critical, distorting the pulleymay damage bearings on the new PS pump.Note: Some new PS pumps may notinclude a new O-ring. Please refer to theappropriate Parts Catalog. 3. Be sure to use only the new O-ringsincluded with the PS pump. The new reser-voir O-ring must be lubricated with OE-spe-cific PS fluid prior to installation. Also make

sure that the control valve O-ring is in its exactgroove position and is NOT covering the pressurebypass hole.4. Bleed the PS system according to the procedures/recommendations in the serviceinformation.Following these procedures and using the correcttools and fluids should help ensure that the new PSpump operates properly. Skipping steps may cost you time and troublelater.

Courtesy of ALLDATA

» TechTips

Most rear wheel drive, and some front wheel drive,vehicles with manual transmissions use a pilotbearing/bushing. The pilot bearing/bushing supports and centers the transmission input shaftand clutch disc. When the clutch is disengaged, thepilot bearing/bushing allows the flywheel to maintain engine RPM while the input shaft is slowing down and stopping. Types of pilot bearing/bushing include conven-tional ball bearings, needle bearings and sinteredbronze bushings.

When a pilot bearing/bushing fails, avehicle may exhibit: • No release; • The transmission may pop out of gear; • Noise; • Vibration; and• Catastrophic failure of the transmission if notfixedEarly signs of the pilot failing may be noise when-ever the clutch is disengaged. The driver may alsonotice that the transmission is difficult to shift

GM: Power steering pump replacement tips

Failing Pilot Bearing / Bushing


» TechTips

between gears or hard to put intoreverse or first gear whenstopped. When the pilot is failing, or hasfailed, the input shaft will beallowed to walk around causing itto go off center. When this hap-pens, the transmission input shaftwill begin moving around insidethe transmission causing the gearsand synchronizers to be off centerresulting in the transmission pop-ping out of gear.If the vehicle has a high outputengine, the misalignment willcause the input shaft gear to notmesh with the counter shaft gearproperly and ultimately will causethe gears to fail. (see figures 1and 2).When a clutch is replaced, thepilot bearing/bushing shouldalways be replaced as part of theservice. Courtesy of Schaeffler Group USA /

LuK �

Figure 1

Figure 2


XADO Atomex Total Flush is an effective complex solutionfor treatment of the engine oil system. REVITALIZANT anda unique combination of special detergent and dispersantcomponents provide cleaning of the oil system up to thelevel of technical cleanliness before changing oil, anticarbontreatment and mobility restoration of the piston rings aswell as creation of an antiwear protection reserve for fric-tion parts of the engine. For more information, visit xado.usReader Service: Go to www.uhsRAPIDRESPONSE.com

CRP Automotive, a source of OE-quality replacementparts for Asian and European vehicles, offers coverageon Asian and European applications with its AJUSACylinder Head Bolt Kit program. The program features aline of torque-to-yield (TTY) head bolts that come pack-aged as sets to meet vehicle specific applications. Thesets are provided in a shrink-wrapped cardboard boxwith assembly lube included.Reader Service: Go to www.uhsRAPIDRESPONSE.com

»Shop

AMSOIL’s new OE Synthetic Automatic Transmission Fluid is available inMulti-Vehicle and Fuel-Efficient formulations. AMSOIL OE Synthetic ATFprovides outstanding protection in normal and severe service, resistingwear on vital parts and extending transmission life. It is thermally stable,guards against the harmful effects of thermal breakdown and helpscomponents stay clean by resisting heat-related evaporation and viscosity loss. Reader Service: Go to www.uhsRAPIDRESPONSE.com

Delphi Product & Service Solutions announced 12 new ignition coilsto its engine management portfolio covering almost 7 million GM,Nissan, Hyundai, Toyota, Chrysler and Volkswagen applications from1986 to 2012. Part numbers: GN10265, GN10304, GN10305,GN10341, GN10345, GN10345, GN10348, GN10349, GN103050,GN10351, GN10352 and GN10333. Delphi ignition coils are backedby a 3-year/36,000-mile warranty. Delphi uses a winding processtechnique to control the length of wire between adjacent windings. Reader Service: Go to www.uhsRAPIDRESPONSE.com


Bar’s Leaks Head Gasket & Cooling Sealant (P/N HG-1) repairs blownhead and intake gaskets, cracked cylinder heads and cooling systemleaks. It can be poured directly into the radiator of a vehicle capable ofidling for 15 minutes without overheating or losing coolant. The liquidsealants contained in Head Gasket & Cooling Sealant are absorbed bythe gasket material, harden, then form a barrier. Head Gasket & CoolingSealant now comes packaged in a box for greater shelf presence andvisibility.Reader Service: Go to www.uhsRAPIDRESPONSE.com

The PlatinumNAPAFilter offers technology for the latest advancements in synthetic oil and performance oil filters. Featuring a host of oil filter innovations,including wire re-enforced fully-synthetic media, ultra-durable HydrogeneratedNitrile compound anti-drain back valve (where applicable), this oil filter providesthe ultimate protection in the NAPA Family of oil filters. Visitwww.napafilters.com for more information.Reader Service: Go to www.uhsRAPIDRESPONSE.com

»Shop


It’s Fast, Easy and Accurate!Get FREE PRODUCT AND SERVICE INFO from the companies featured in this issue of Underhood Service.

Advertiser Page Advertiser Page Advance Auto Parts Professional 35Airtex Corporation Cover 2, 1, 34AST 36Auto Value/Bumper to Bumper Cover 4Automotive Service Equipment 51Bar's Leaks 14Bosch Automotive Service Solutions 5CARQUEST Auto Parts 3CRP Industries 21Dipaco Inc. 38ETE Reman 17Federated Auto Parts 24, 25Fram Filtration 31Intermotor by SMP 9Jasper Engines & Transmissions 47Motorcraft,Ford Motor Company 13, 43NAPA Cover Call Out, 15NGK Spark Plugs 37Nissan Motor Corp. USA Cover 3O'Reilly Auto Parts 7

Penray 44Perfect Stop 40, 41Schaeffler Group USA 10, 11Toyota 28, 29TYC/Genera Corp. 23US Motor Works 45VISION HiTech Training & Expo 30Wells Manufacturing 19WIX Filters 27

>> VISIT www.uhsRapidResponse.com and click on the company from which you want information.

>> OR, go to www.UnderhoodService.comand click on the Underhood Service Rapid Response Logo.

Reader Service: Go towww.uhsRapidResponse.com

WANT DETAILS ON THE PRODUCTS & SERVICES YOU SEE IN


DI R E C T C L A S S I F I E D S


Advertising RepresentativesThe Tech Group

Bobbie [email protected], ext. 238

Jamie Lewis [email protected] 330-670-1234, ext. 266

Dean Martin [email protected] 330-670-1234, ext. 225

Sean [email protected], ext. 206

Glenn [email protected], ext. 212

John Zick [email protected] 949-756-8835

List Sales Manager Don [email protected], ext. 286

Classified Sales Tom [email protected], ext. 224


Call now to order or to receive a free 2012 catalog 1-800-434-5141www.autobodysuppl ies.com

Why switch to PDQ? PRICES. Low prices. High Quality. Always.1st time buyer? Order from this ad and receive these special prices.


»DiagnosticLogic By Andrew Markel

The perfect internal combustion vehicle wouldbe able to put the exact amount of fuel and airinto the combustion chamber. If the perfectcombustion event happened, you would get

nothing more than water and carbon dioxide. Therewould not be any unburned fuel or oxygen. It wouldalso be at the right temperature so oxides (“hyperac-tive” oxygen turned on by higher temperatures) wouldnot combine with nitrogen and carbon to form nitricoxides (NOx) and carbon monoxide (CO). This perfectcar would not need a catalytic converter or any otheremission-control device. We are not there yet,in the mean time, wehave exhaust gasrecirculation systems(EGR), secondary airinjection and catalyticconverters.

EGR SystemsEGR systems put asmall amount of inert gasinto the combustion cham-ber to control the tempera-tures. Since exhaust gases donot typically burn, this lowersthe combustion temperature andreduces NOx emissions from the engine.When things heat up in the combustion chamber totemperatures around 1,300° C or 2,500° F, oxygen andnitrogen start combining with each other and formNOx and CO. By putting exhaust gases into the combustion cham-ber, the air fuel mixture is watered down by the inertexhaust gases. This slows down the combustionprocess and lowers combustion temperatures to lev-els where NOx does not form. Unlike older EGR systems, modern EGR systemswork constantly, not just during deceleration orclosed throttle conditions. Newer vehicles with vari-able valve timing on both exhaust and intakecamshafts can adjust timing so that a small amountof exhaust gas is sucked back into the chamber dur-ing the intake stroke.

Secondary Air Injection SystemsSecondary air injection systems pump outside airinto the exhaust stream so unburned fuel can beburned. Early systems have a belt-driven air pump.Newer aspirated systems use the vacuum created byan exhaust pulse to pull air into the pipe. The latestsystems use an electric motor to pump air. These sys-tems are critical for the life of the catalytic converter.Electric motor systems can be found on many newvehicles like the GM LS series, Toyota V8s andCalifornia emission Ford 3.8 V6s and 2.0 four cylin-

der. These systems typically areactive during the first 20 to 120seconds of engine operation byforcing air downstream into theexhaust manifolds to oxidize the

hydrocarbons and carbon monoxide createdby running rich at startup. The system injectsthe correct amount of air using inputs likecoolant temperature, air temperature andoxygen sensors.

Catalytic Converter Under ideal conditions, a three-way catalystcan reduce somewhere between 50% and95% of NOx emissions and 99.9% of the

unburned fuel. It is the last stop for pollutants, and ifan emissions system upstream is compromised, it canonly compensate so much before tailpipe emissionsincrease.

DiagnosticsTo properly diagnosis a high-emission vehicle, youmust look at it like an engineer looking at the entiresystem, from the air intake to the exhaust pipe. Whena vehicle is engineered, it must meet a specified emis-sion level. To do this, an engineering team will bal-ance the systems and make them work in harmonyso the price is affordable. If a vehicle has a combustion chamber design thathas higher than normal temperatures, the engineerswill balance out the amount of exhaust gases intro-duced to the combustion chamber to the size of theconverter so the vehicle meets mandated emissionlevels and the warranty period. �

EGR and Secondary AIR Systems

Underhood Service, February 2014

Documents

Transcript of Underhood Service, February 2014