underhood serivce

®A MAGAZINE

Feature: Dissecting PCMs Tech Talk: Biodiesel or Bio Mess? Gonzo’s Toolbox: Handling 'Helpers'

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CONTENTS

EditorEdward Sunkin, ext. 258email: [email protected]

Managing Editor Jennifer Clements, ext. 265email: [email protected]

Technical Editor Larry Carley

Contributing Writers Gary Goms, Scott “Gonzo” Weaver, Bob Dowie and Randy Rundle

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

PublisherJim Merle, ext. 280 email: [email protected]

Ad Service Director Cindy Ott, ext. 209email: [email protected]

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

2 February 2013 | UnderhoodService.com

2.13Volume XVIII, No. 2

30Tech FeatureDissecting PCMs

Contributor Omar Trinidad providesan in-depth analysis of how sensor circuits are designed, how the powertrain control module (PCM)interprets the signal voltage and thecriteria that trigger the module to setdiagnostic trouble codes (DTC).

®®

A Publication

30

4022

22Diagnostic DilemmasApproaching No-Code Diagnostics

In this installment of DiagnosticDilemmas, technical contributor Gary Goms discusses in detail how he approached the no-code, intermittentdriveability complaints of three different vehicles — a Jeep Cherokee,a Toyota Camry and a Ford Mustang.

40Tech TalkBiomass or Bio Mess?

Diesel specialist Bob McDonald takes a look into the misconceptionssurrounding diesel bio-fuel. His resultsmay surprise you, no matter whichside of the fence you sit on regardingthe use of bio-fuels in your customer’s vehicle.

DEPARTMENTS

6 Directions

8 Aftermarket Update

16 Gonzo’s Toolbox

46 Tech Tips

50 Products

51 Rapid Response

52 Classifieds

56 Test Drive

56 Guess the Car

A Publication

Brent Crago, ownerTop Tech AutomotiveCleveland, Tennessee

Marc Duebber, owner Duebber’s Auto ServiceCincinnati, Ohio

Audra Fordin, owner Great Bear Auto Repair Flushing, NYwww.womenautoknow.com

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)

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Over the past few years, theautomotive industry hasfocused on plug-in electric

vehicles and various gasoline- anddiesel-electric hybrid designs; butnow, electric fuel-cell vehicles arereturning to the spotlight.Recently, a collaborative partner-

ship approach between Daimler,Ford and Renault-Nissan wasannounced in an effort to beginmass producing hydrogen-fueledfuel-cell electric vehicles (FCEVs)in the next four years.

The benefit of these zero- emissions vehicles is their potential to reduce pollution andcut down on the world’s relianceon oil for transportation.However, the drawback over the

years has been cost. The automak-ers believe that combiningresources could help alleviate thelargest challenge for such vehicles— a fueling infrastructure.Powered by electricity generated

from hydrogen and oxygen,FCEVs emit only water whiledriving. FCEVs are consideredcomplementary to today’s battery-electric vehicles and willhelp expand the range of zero-

emission transportationoptions available to consumers.While each vehicle is expected

to use the same electric coredesign and components, modelswill still be unique to eachautomaker. This allows manu-facturers to offer different bodystyles, cabin designs and brand-ing to buyers.But the concept of sharing fuel-

cell core platforms and compo-nents would also be helpful for

repair shops in the future, asdiagnostic tools used to servicethese vehicles could also beshared, instead of shops pur-chasing tooling for individualmanufacturers. It also would be helpful for the

Society of Automotive Engineers(SAE) to become involved withthe alliance as well as other OEMsto create conformity in fuel-cellcomponents and connectors. “Working together will signifi-

cantly help speed this technologyto market at a more affordablecost to our customers,” said RajNair, group vice president, GlobalProduct Development, Ford

Motor Company. “We will allbenefit from this relationship asthe resulting solution will be bet-ter than any one company work-ing alone.”Daimler’s research division had

reported in the past that itplanned to commercialize fuel-cell vehicles by 2015. However,it did not appear that this goalwould have been met, and part-nering in this alliance will helpthe automaker provide such carsjust a few years later thanexpected.While FCEV technology has

been in the development stage fora number of automakers includ-ing General Motors and Toyotasince the late 1990s, the implementation of a consumervehicle hasn’t taken off due to thehigh costs of development, designand patents. Hydrogen fuelingstations have been introduced inthe U.S., but are mainly concentrated around FCEV testing areas out West. Under the alliance agreement

from Daimler, Ford and Nissan,each company will invest equallyin the technology. The cars couldbe available as early as 2017.According to a release from the

alliance, “The collaboration sendsa clear signal to suppliers, policy-makers and the industry toencourage further developmentof hydrogen refueling stationsand other infrastructure necessaryto allow the vehicles to be mass-marketed.”


» Directions BY Edward Sunkin | EDITOR

Selling the Fuel-Cell Concept


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

» Aftermarket UpdateBrought to you by:

Ford’s Modular engine, used in various Ford,Lincoln and Mercury products during themid- to late-2000s, has been known to

give techs a hard time during a spark plugreplacement. The problem lies with excessive car-

bon buildup on the plugs, espe-cially on engines that havegone beyond an OEM-rec-ommended replacementinterval. This can cause aplug to break in thechamber during itsremoval, creating stresson the tech and additionallabor time to remove thedamaged component.Techs we talked to

advised addressing theissue before it can becomea problem — meaningreplace the plugs prior totheir recommendedreplacement interval. That,obviously, can be a hard sell toyour Ford driving customers.Some techs who have come across

the broken plug problem recommendperforming an engine flush the dayprior to changing out the spark plugs andletting the vehicle sit overnight as a way toloosen up the carbon deposits, allowing forless of a chance for a plug to break. This too,might not be an option, since there are many cus-tomers that expect a spark plug replacement job tobe completed the same day.

Damage Control: Plug RemovalTechniques on Ford Modular Engines

VEHICLES WITH THE PLUG REMOVAL ISSUE:• Ford: 2005-’08 Mustang; 2004-’08 F-150; 2005-’08 Expedition and

F-Super Duty; 2006-’08 Explorer and 2007-’08 Explorer Sport Trac• Lincoln: 2005-’08 Navigator and 2006-’08 Mark LT• Mercury: 2006-’08 Mountaineer


Ford recognized the plugremoval problem and issued atech bulletin — TSB 08-7-6 — toaddress the problems associatedwith plug removal on variousFord vehicles. This article super-sedes TSB 08-1-9.According to Ford, some F-150s,

Mark LTs, F-Super Dutys,Expeditions and Navigators withthe 5.4L 3V engine; Mustangs,Explorers, Mountaineersand Explorer Sport Tracswith the 4.6L 3V engineand F-Super Dutys withthe 6.8L 3V engine mayexperience difficulty withspark plug removal. Thismay cause damage to thespark plug and leave partof the spark plug in thecylinder head.Affected engine build

dates are as follows: 5.4L3V and 6.8L 3V before Oct.9, 2007, 4.6L 3V beforeNov. 30, 2007. The enginebuild date can be read on

the left-hand cam cover informa-tion sticker.To remove the spark plugs on

these engines without damage, itis necessary to adhere exactly tothis procedure before removal isattempted.Caution: Do not remove plugs

when the engine is warm or hot.The engine must be at room tem-perature when performing spark

plug service. Removing the sparkplugs from a warm/hot engineincreases the chance the threadscould be damaged.

Spark Plug RemovalProcedure

1. Remove the coil-on-plugassemblies and thoroughly blowout the spark plug wells and sur-rounding valve cover area with

compressed air. 2. Back out the spark

plugs no more than 1/8to 1/4 of a turn. UsingMotorcraft CarburetorTune-Up Cleaner, fill thespark plug well justabove where the jambnut hex sits (1/2 - 3/4teaspoon). A minimumperiod of 15 minutes ofsoak time is required.The cleaner will wickdown to the groundelectrode shield andsoften the carbondeposits in this time. Donot work the spark plug

back and forth at this point. Caution: Excessive Motorcraft

carburetor tune-up cleaner, orrepeating the process severaltimes with too much cleaner fluid,could introduce enough liquidvolume to hydro-lock the engine.3. Tighten, and then loosen the

spark plug, working the plug backand forth. Some screeching andhigh effort may be noticed. Theexpected removal torque is about33 lb.-ft. (45 Nm). Repeat the backand forth turning as needed untilturning effort is reduced, andremove the spark plugs.Ford says do not use power tools

for the plug removal — sparkplugs must be only be removedwith hand tools.


Figure 1: New plugs should be installed using afilm coating of Motorcraft high-temperaturenickel anti-seize lubricant on the ground elec-trode shield. Do not coat the electrode strap.

» Aftermarket Update

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Separated/Broken SparkPlug RemovalIf the spark plug separatesafter following the Spark PlugRemoval Procedure, it will failin one of three modes. Refer tothe appropriate removal proce-dure as required.• Mode 1: The ground elec-

trode shield is left behind as anempty shell. (See Figure 2.)• Mode 2: The entire porce-

lain insulator and ground elec-trode shield remains in thecylinder head. • Mode 3: The upper section of

porcelain broke off with remain-ing porcelain left inside theground shield.

Mode 1 Procedure:Use Rotunda special service tool303-1203 to remove an emptyground electrode shield from thecylinder head. Note: This tool is only designed

to work with an empty groundelectrode shield. If porcelainremains, proceed to Mode 2 or 3removal.1. Modify vacuum cap to a 3/8′′

(10 mm) length for each groundelectrode shield that needs to beremoved. 2. Use the installation rod pro-

vided with service tool 303-1203update to install the modified vac-uum cap. Push the cap into theground shield down to the elec-trode strap. This will plug andprotect the combustion chamberfrom contamination. 3. Thread-tap the ground elec-

trode shield using a 9.0 x 1.0 mmplug tap (tap profile is about 3-4reduced diameter threads on thetip end).a. Coat the end of the tap with

general-purpose grease. b. Turn the tap about three to

four turns into the ground elec-trode shield. Back the tap up fre-quently to break chips and avoidcut material from coiling-up in thespark plug well. A tap socketadaptor is provided with servicetool 303-1203 update to connectthe tap to a 3/8′′ socket drive.Caution: Do not attempt to

remove the ground electrodeshield with the tap and wrench.The tap may break if this isattempted.4. Thread Rotunda special serv-

ice tool 303-1203 into the groundelectrode shield. See Figure 3 onpage 14.a. Install the stepped end of the

tool pilot bushing into the sparkplug well ensuring it bottoms out. b. Screw the center shank into

the ground electrode shield. Donot over tighten the shank, to prevent thread stripping. c. Install the nylon washer and

jack nut until finger tight. d. Turn the jack nut until the

ground electrode is freed from thecavity and withdraw the toolassembly.

Mode 2 Procedure:1. Add an additional 1/2 tea-

spoon Motorcraft CarburetorTune-Up Cleaner fluid into spark

» Aftermarket Update

Figure 2


» Aftermarket Updateplug well and allow 15 minutes ofsoak time. 2. Using long-nose pliers, grasp

and remove the porcelain with anup and down motion taking carenot to fracture the porcelain. 3. Refer to Mode 1 Procedure to

remove the remaining groundelectrode shield from the cylinderhead.

Mode 3 Procedure:Caution: Do not drive porcelaindown into the ground shield witha punch as fragments may enterthe combustion chamber.Note: Use Rotunda special serv-

ice tool kit 303-1398 to removeporcelain broken inside theground electrode shield. Caution: The engine and the

bonding adhesive must be roomtemperature of 70° F (21° C) orhigher for proper cure and bondstrength. Verify the expirationdate of the adhesive.Caution: Do not reuse pins from

the tool kit. This ensures the correct surface characteristics forbonding.1. Remove any remaining elec-

trode material from broken porce-lain with long-nose pliers. 2. Spray Motorcraft Metal Brake

Parts Cleaner into the porcelain

hole for two to fourseconds using thestraw nozzle suppliedwith the brake cleanercan. 3. Using the tool kit,

insert a pin into thecollet. Screw the colletonto the threaded rod.Install the assembledcollet, pin and thread-ed rod into the steeltool pilot. 4. Retract the collet

and pin into the steeltool pilot, protectingthe pin. Note: Pin tip damage

or bent pins will pre-vent insertion into theporcelain.5. Insert the complet-

ed assembly into the spark plugwell and fully engage the pin intothe porcelain. See Figure 4. 6. Spray Motorcraft Metal Brake

Parts Cleaner two to four secondsbetween the spark plug well andsteel tool pilot. The steel tool pilotmust be lifted up approximately1/2” to allow brake cleaner toflood the porcelain and pin.7. Scrub the porcelain inside

diameter by moving the threadedrod up and down vigorously.

Take care making sure the pindoes not disengage the porcelain. 8. Repeat steps 6 and 7. 9. Remove the tool assembly.

Again flood the porcelain withMotorcraft Metal Brake PartsCleaner for two to four seconds,then blow out the entire sparkplug well and porcelain with drycompressed air. Note: Clean and dry components

are key to bonding the pin to theporcelain.10. Repeat steps 1-9 to prepare

remaining porcelain fragments asneeded.11. Disassemble the collet and

pin from the threaded rod. Drythe tools thoroughly with drycompressed air.

Figure 4

Figure 3

For additional informationand steps for using the bonding agent, e-mail us [email protected] for acopy of TSB 08-7-6.


There are times when Ifind I have more helpersin the shop than I have

on the payroll. I didn’t ask forthis extra help, but there theyare, right in the middle of theshop. Who are they, and wheredid they come from? Ah, yes,it’s those customers who wantto keep an extra eye on theirride.

It’s pretty sneaky how theymanage to get past the frontdesk, the waiting area,through the service door andthen squeeze by the tire racks.For safety reasons, it’s bestthat customers stay in thewaiting room. But some ofthese adventurous individualsare compelled to help me out,no matter what.

There are too many hoses,cords and dangerous types ofequipment to be spending theafternoon in a place withwhich you are not familiar. Alot of times, an unsuspecting

“helper” won’t notice thatfloor jack, or those sharp toolsat the edge of the workbench.The possibility of encounter-ing danger just doesn’t matterto some of these new helpers.They’ll still want to wanderinto the bay and “help” meout.

I can usually spot who’sgoing to be the next shophelper. All I have to do is pull

their car into the shop. Ifthere’s a fresh, icy drink in thecup holder, an open pack ofcigarettes and lighter lying onthe passenger seat, and a bookor a laptop, there’s a goodchance they’ll be poppingtheir head around the corner.

“Do you mind if I get mydrink out of the car?” my newshop helper will ask.

Well, I just can’t say no.Now, sometimes they’ll grabtheir drink and head rightback to the waiting room.Other times, I’m not thatlucky. It’s their perfect excuseto hang around the car.

Soon, the new shop helperis leaning over the fenderwith their ice-cold drink,watching the process of mefiguring out what’s up with

By Scott “Gonzo” Weaver

» Gonzo’s Toolbox

It’s pretty sneaky how customers manage to get past the front desk, thewaiting area, through the service doorand then squeeze by the tire racks. Forsafety reasons, it’s best that they stay

in the waiting room. But some of theseadventurous individuals are compelled

to help me out, no matter what.

Dealing With Customers WhoFind Their Way Into Your Bay

Handling Temporary Helpers

“What do you think it is?”


their ride.At times, it’s rather

interesting; at other times, it’ssimply annoying. I can nevertell until the conversationstarts. If the first question is,“What do you think it is?” Iknow it’s going to be one ofthose days. Like most newhelpers, they’re unaware of thedangers of posing such an inap-propriate and pointless ques-tion at this point in time. I’drather not guess at this stuff. IfI’m wrong, the next thing youknow is that I’m trying toexplain why whatever Ithought it was is “not the prob-lem.” Thinking just gets meinto trouble. It’s always best toverify, diagnose and then repairthe problem.

“Let’s run some tests, andthen we’ll know for sure,” I tellthem. Some realize that they’reout of place and should proba-bly stick to watching the ice intheir drink melt. But, for others,it wouldn’t take much to havethem reach over and pick up awrench or two. They’ll lean onthe A/C recovery machinewhile it’s running as if it’s anold-fashioned hitching post, orstick their head through thepassenger window while I’m

under a dash.I have to keep from laughing

as I watch their jumpy reactionsto the recovery machines’ unex-pected clicks and groans, whilethey stand there trying to actcasual. And, no matter howclumsy they may look with allof their uncoordinated antics,they’re still going to keep afirm grip on that drink.

This little trip into the back ofthe shop isn’t so much to checkup on their car, but a way toobserve the process of diagnos-ing the problem. It’s as if itwere some sort of exhibition.They’ll look high and lowthroughout the shop, take a fewsips from their drink and thenpay attention to what I’m doing

to see how I determine what’swrong.

The new help will concen-trate on what I’m doing, so theycan go home and tell theirfriends about some sort ofcrazy-looking machine, ordetail a technique they watchedme perform on their car.

I guess in another decade ortwo, I’ll be the old guy hangingaround the next generation’srepair tech. There’s no doubtI’ll be that unwanted temporaryhelper telling stories about howI used to fix cars, too. Yep, thatday is coming. I don’t knowwhen, but it’s coming. Guess Ibetter prepare. Now where didI put that ice-cold drink?

» Gonzo’s Toolbox

A lot of times, an unsuspecting “helper”won’t notice that floor jack, or thosesharp tools at the edge of the work-bench. The possibility of encounteringdanger just doesn’t matter to some ofthese new helpers. They’ll still want towander into the bay and “help” me out.


Thanks to the increasing reliability of mod-ern vehicles, most diagnostic technicians areseeing fewer pattern-failure driveability

complaints. For that reason, many techs won’tgamble expensive shop time chasing an illusiveno-code driveability complaint. Instead, many willwrite “no problem found” on the repair order andmove on to the next vehicle.

Unfortunately, at some point in time, the inter-mittent, no-code driveability will either besolved or the vehicle will be traded or sold forscrap. This month’s Diagnostic Dilemma willdiscuss in detail how I approached the no-code,intermittent driveability complaint on three different vehicles.

The Stalling CamryLast summer, I encountered a customer with ano-code, intermittent stalling complaint on a1997 Toyota Camry. According to the customer,the stall most often occurred during enginewarm-up or would manifest itself as an occa-sional hesitation at road speeds. Although well-maintained, this vehicle had rolled up in excessof 200,000 miles. At this point, the crankshaftposition (CKP) sensor had been replaced withno result. While I don’t believe in searching for silver bul-

lets, I do believe in doing preliminary research byconsulting a professional database for technical

and anecdotal case-study information.It didn’t take but a few minutes online to deter-

mine that a faulty engine coolant temperaturesensor (ECT) was causing many Camry stallingcomplaints. The simplest procedure might havebeen to replace the relatively inexpensive ECTand let the customer drive the vehicle to verifythe repair. But, because just about any othercomponent in the engine management systemcould also cause a similar stalling complaint, Idecided to pursue a more complete diagnosis.

As part of my Standard Operating Procedure, Icleaned the throttle plate assembly with throttleplate cleaner with a toothbrush and followed upwith solvent-penetrating oil that lubricates thethrottle plate and bore.

Next, I tested the battery for state of charge(SOC) and state of health (SOH), and checkedthe voltage drop at both battery terminals.

»DiagnosticDilemmas

By Gary Goms, technical contributor

1 997 Toyota Camry

UnderhoodService.com 23

Although the battery terminalspassed both tests with less thana 0.5-volt drop, it’s important toremember that the terminal-to-cable connection on Toyota bat-tery cables can conceal severecorrosion, so I physically tookthese connections apart andcleaned those surfaces. I alsophysically inspected the ECTsensor, throttle position (TP)sensor and idle air control (IAC)connections and used the graph-ing feature on my scan tool towiggle-test each circuit to verifythat these sensors didn’t haveany broken wires.Before starting the engine, I

connected my scan tool to theToyota so I could record coolant

temperature on the data graph.Luckily, I felt the engine “hic-cup” as it warmed up andpushed the “save” button on myscan tool to store the image.After recovering from thatminor stall, the engine ran with-out fail for another 30 minutes.

As Photo 2 indicates, the indi-cated ECT plunged from +14° Fto -4° F for just a few millisec-onds, with the engine rpm drop-ping a few rpm as well. For me,this was the smoking gun thatproved the ECT sensor was atfault. At that point, I replacedthe ECT sensor and asked theowner to report back if he hadanother stalling problem.So why wasn’t an ECT-related

» DiagnosticDilemmas

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Photo 1: The ECT (green connector) appeared to be a frequent culprit inmany stalling complaints.

Photo 2: Notice that, as the indicated coolant temperature plunges to -4° F, the data graph indicates a small but sharp dip in engine speed.


diagnostic trouble code (DTC) stored in the PCM’sdiagnostic memory? Let’s keep in mind that anyfailure must meet the enabling criteria required tostore an applicable DTC. Because seven differentgeneric ECT-related codes are listed for this appli-cation, I can’t list their enabling criteria in thisspace. But, while this glitch didn’t last long enoughto store a code, it did last long enough to richenthe air/fuel mixture ratio and stall the engine atidle speed.

The Stalling CherokeeWhile the engine management technology on a1996 Jeep Cherokee might be obsolete, the diagnostic methods used to find the cause of anintermittent, no-code stalling complaint are not.What makes this case unusual is that the Jeep is aright-hand-drive model driven by an independentcontractor on a daily rural free delivery mail route.Given the replacement cost for a right-hand-drivevehicle, the owner elected to spend whatever itmight cost to keep this Jeep running.

Off the top, the Jeep had a new TP sensor, IACvalve, new ignition coil and remanufactured dis-tributor installed, presumably to remedy thestalling complaint. All of the above indicated thatthe problem might turn out to be a real head-scratcher, which it proved to be.

Once the vehicle was warmed up, it might bedriven for hours without stalling. Other times, thestalling complaint occurred so frequently that thevehicle was impossible to drive. After I began testing, the engine idled from a cold-soak for 30minutes and then stalled. Thanks to my long experience with Jeep systems, I had a two-channellab scope connected and ready to record the CKPand camshaft position (CMP) sensor waveforms. Photo 3 illustrates the correct relationship

between the CKP and CMP sensors. Notice thatthe green trace at the top is the CMP sensor, whichindicates whether the No. 1 cylinder is on a com-pression TDC or exhaust TDC stroke. Notice alsothat the CMP “on” signal below covers four Hallsensor signals indicating the positions of threecylinders while the remaining three cylinders arecovered by the “off” CMP signal. Needless to say,the CMP signal went straight-line when the enginestalled.Since remanufactured distributors can have their

problems, I elected to replace the Hall sensor witha premium-brand CMP sensor. In doing that, I alsorecognized that the failed CMP sensor was a sec-ondary, rather than primary, cause of the stallingcomplaint. I might add that, because it takes about20-30 minutes for the distributor to reach enginetemperature, this time period alone was enough tomake me suspect that the CMP sensor was failing.

After I replaced the faulty CMP sensor, theengine again stalled after about an hour of run-ning time. Here again, I’m guessing that the stallmight be caused by a temperature-related failurein one or more components. Since I couldn’t estab-lish a relationship between the PCM’s temperatureand the stalling complaint, I began to suspect theCKP sensor.

Since a visual inspection revealed that the CKPsensor had recently been replaced, I began to looka little deeper for the cause of the stalling com-plaint. For example, the PCM had reached about130° F hot-soak temperature. At this point, Iremoved the PCM connector to check for possible

1 996 Jeep Cherokee

Photo 3: This waveform illustrates a perfect cam/cranksynchronization on a Jeep 4.0L engine.




corrosion. Before reassembling, I coated the connector pins with some Stabilant-22 connectivity-enhancing agent and cleaned all chassis groundsand both battery terminals. I also verified the bat-tery’s SOC and SOH.I was certain that the stalling problem wasn’t

being caused by the IAC valve because I couldhear a noisy sucking sound as the IAC began toopen up as the engine stalled. I also believed thatthe throttle sensor wasn’t at fault because, in mostcases, an erratic TP sensor voltage at idle willcause the PCM to increase, rather than decrease,engine idle speed. Nevertheless, since the IAC andTP circuits share a ground circuit on this applica-tion, I connected a DVOM set at the min/maxfunction to record any discrepancies in the TPground.

As with the previously mentioned Toyota Camry,the most valuable tool in locating potential wiringfaults and sensor failures is the data graphing

feature included in most scan tools. In this case, Imonitored the synchronization between the CMPand CKP sensors.

As shown in the data capture in Photo 4, a loss ofcam/crank sensor synchronization is extremelyimportant because it indicates that the CKP sensormight be momentarily failing to synchronize withthe CMP sensor. Although a two-channel lab scopeand scan tool was connected to the engine torecord cam/crank sensor data, it was extremelydifficult to capture the failure as it occurred.

In any case, the suspected CKP failure happenedso quickly that I couldn’t capture it on either tool. Iexperimented with setting my lab scope on normaltrigger and still had a normal cam/crank synchpattern at the time of failure.

But there were clues. First, the stalling conditionrequired about an hour of warm-up time from anovernight cold-soak. Second, each stalling incidentincluded a loss of cam/crank synch. So I speculated

Photo 4: Although the baro pressure is irrelevant to the diagnosis, the loss of the cam/crank sensor synchroniza-tion is extremely important.

Photo 5: Notice the disappearance of rpm and the declining CMP count as the engine begins to stall.


that it might take about an hour for the CKP sen-sor located on the bell housing to warm up fromcold-soak to engine temperature.

Keep in mind that, because the failure occurredonly after an hour running time from cold-soak,this testing procedure was becoming very time-consuming. I will say that I am equipped to dealwith this type of diagnostic scenario more so thana technician working in a production situation.Once I understood the time frame, I could warmthe engine up and work on other projects. But, atsome point, it’s also mathematically cheaper toreplace suspect parts than to test to the point offailure.So at this point, I replaced the CKP sensor and

ran the Jeep through several more warm-up cycles.Here again, I’m not sure that the PCM was pro-grammed to recognize a CKP glitch that evidentlyoccurred just for a few milliseconds. Fortunately,the engine didn’t stall during several cold-soakwarm-ups. Because several road tests also con-firmed a no-stall condition, the vehicle was deliv-ered to the customer and, presumably, it’s still run-ning just fine.

No-Code Mustang MisfireLet’s take a brief look at a no-code misfire complaint on a 2002 Mustang equipped with the3.8L engine and automatic transmission and withabout 120,000 miles on the odometer. Because this car belonged to a young, do-it-your-selfer friend of mine, I recommended that he bring

his maintenance up to date by installing new sparkplugs and wires. None of that, of course, solvedthe misfiring complaint.

Fortunately, my friend claimed that his Mustangmisfired most frequently as throttle was appliedfrom a 60 mph cruise condition when climbing anearby hill. At wide-open throttle (WOT), the mis-fire would disappear. Long story short, I verifiedthe identical symptoms and recorded exactly 41misfires during the half-mile climb up the hill.

As most of us know, misfires can be caused byfuel, ignition, compression and timing problems.In this case, the seat-of-my-pants indicated a badsecondary misfire. One diagnostic scenario is thatthe misfire occurs only at part-throttle because theair/fuel (A/F) mixture ratio is transitioning fromlean to rich. A contributing reason is that the run-ning compression in the cylinders increases as thethrottle is opened. So, during lean cruise, the engine doesn’t build

enough cylinder pressure to cause the misfire, but,as the throttle is opened, the lean A/F mixturebegins to increase firing voltages. Once the throttlereaches WOT, the fuel mixture richens enough toreduce firing voltages and eliminate the misfire.

The reason no misfire codes were stored is that 41misfires during a half-mile interval isn’t enough tostore a P0300-series DTC. So after returning to theshop, current-ramping the ignition coils indicated nofailures in the primary ignition circuits or drivers.

At this point, I’m speculating that the waste-sparkignition coil has a potting failure in the epoxy com-pound used to insulate the coil windings and formthe coil body. So the coil developed an internalshort that was sensitive to spark demand createdby both running compression and air/fuel mixtureratio. A new coil fixed this intermittent, no-codemisfire complaint.

2002 Ford Mustang

Photo 6: This Mustang had an obvious part-throttlemisfire problem, but no P0300-series code to gowith it.



Dissecting theControl ModuleUNDERSTANDING CIRCUIT DESIGNSTO IMPROVE DIAGNOSTIC SKILLSBy Omar Trinidad, assistant professor, Southern Illinois University

With the complexity of automotive electrical systems increasing steadily, manufacturers have developed troubleshooting trees and strategies(see example above) to make it easier for techni-cians to diagnose problems. These steps andstrategies are very helpful for technicians whenfollowed, but they can also prevent them fromusing their cognitive skills.

Therefore, it’s veryimportant for techniciansto understand how sensorcircuits are designed, how themodule interprets the signalvoltage, and the criteria that trig-ger the module to set diagnos-tic trouble codes (DTC).This article will help explainhow switch inputs and vari-able resistive-type sensor cir-cuits are designed, and providesimple electrical diagnostic tips.

What Lies BeneathWhen looking at a wiring schematic, it’s temptingto wonder what lies within the box representing acontrol module. The fact is, these thoughts usuallyarise when the technician is already frustrated at avehicle in his bay. Although it’s interesting to knowwhat lies within the depths of a module, the mostimportant parts to understand are the pull-up (PU)and pull-down (PD) resistors (see Figure 1). Understanding these two components and

applying basic electrical principles will explainhow most sensor circuits are designed. The mostimportant point to remember is that switch inputsor variable resistive-type sensors do not producetheir own voltage, they merely control or changethe voltage measured by the module. All modules— including the power control module (PCM),transmission control module (TCM) and bodycontrol module (BCM) — utilize the same inputcircuit design. These resistors are also used formonitoring outputs and other sensors, but thisarticle will focus on switch inputs and variableresistive-type sensors.

» TechFeature CONTROL MODULES

...Turn the ignition switch to the ON position. Test voltage at terminal 2 of connector C302. Is the voltage 4.92V or higher? If yes, go to step 4. If no, check for bad connections...

Figure 1

Dissecting theControl Module

» TechFeature

Basic PrinciplesPull-up and pull-down

resistors are utilized formany electronic purposes, butthey’re mainly used to allow sig-nal voltage to change based onresistance changes in the sensoror switch, and enable the moduleto recognize circuit faults basedon that signal voltage. These re-sistors are inside the module andare in series with each switchinput or variable resistive sensor. The module measures the volt-

age between the two resistors, orbetween the resistor and theswitch, to infer the status (resis-tance) of the sensor or switch.Without these resistors the voltagebefore and after the sensor wouldnever change regardless of anyresistance changes in the sensor. In order to understand how

these sensor circuits function, it’simportant to understand twobasic electrical principles. First,positive and negative

voltage/electrical pressure willbuild up at the highest resist-ance. Last, if two resistors arewired in series, the resistor withthe highest resistance will dropor build up the mostvoltage/electrical pressure.

Switch Input CircuitsFigure 2 illustrates one switch inthe ON/closed position and theother in the OFF/open position.This particular circuit is designedto allow the module and the tech-nician to measure 0 volts whenthe switch is closed and 5 voltswhen the switch is open. Switchinputs such as a brake, door orwindow switch utilize the firstelectrical principle. Due to the fact that the switch

would be the highest resistancewhen the switch is open, thepositive voltage and negativevoltage will meet at the switch.This explains why a technicianand the module would measure5 volts at the sensing side of theswitch. On the contrary, a tech-nician’s meter would read 0

volts when the switch is closedbecause the positive and nega-tive potentials would meet at the4Ω resistor, which is the highestand only resistor in the circuit.The meter won’t see a differencein potential between the twoleads and will indicate 0 volts ifthe switch is closed with oneDVOM lead on a chassis or battery ground and the otherlead on the switch sensing side.Notice that this example uses aground-controlled circuit with a5-volt reference. Some circuits,similar to one that will be discussed later, use a power-controlled 12-volt circuit.

Variable Resistive Input Circuits Using the second electrical princi-ple listed above, Figure 3 on page32 illustrates the fact that the re-sistance of the second resistor af-fects the voltage reading before it.A higher resistance would buildup more voltage/electrical pres-sure before it, and the opposite re-sult would occur if the resistancedecreased. This type of circuit isutilized in variable resistive-typesensors such as the engine coolanttemperature sensor (ECT), throttleposition sensor (TPS) and ambientlight sensor (ALS). Differing from a conventional

conductor, the ECT is constructed of a


Figure 2

***Not Actual Values***


semi-conductive material that decreases in resist-ance as temperature increases. This explains whythe signal voltage to the PCM decreases as temper-ature increases. An increase in temperature willcause the ECT to decrease in resistance, thus build-ing up less voltage/electrical pressure between thePU resistor and ECT. The PCM is programmed tointerpret the signal voltage as an indication ofengine coolant temperature. From this information,the PCM can initiate closed loop, enable monitorsand perform other emissions-related functions. Conventionally, a contact-type ignition switch

directs high current to most of the electrical sys-tem. But with the implementation of push-start,advanced anti-theft and other body control func-tions, the ignition switch is now merely an input toa module rather than a high current switch. Evennon-push-start systems with conventional lock-cylinders and keys can utilize this design. Thesesystems have a specific fixed resistor for each key

position. Figure 4 illustrates a 1.3K Ω inside theignition switch in series with a PD resistor insidethe BCM. The BCM will reference the ignitionswitch position based on the voltage between thetwo resistors. Once the BCM informs the ECM thatthe key is in the start position and the shifter is in

park or neutral, the ECM will send posi-tive voltage to the control side of thestarter relay.

Diagnostic Trouble CodesUnderstanding basic electrical principlesand sensor circuits will allow any techni-cian to efficiently diagnose any complexcomputer-controlled system. However, dueto the current compact design of connec-tors and wires, it’s now very difficult to acquire any voltage measurements at aconnector through probe-type tools such asa t-pin. Fortunately, using a scan tool,DVOM and a jumper wire kit can alleviatethis problem.It’s always wise to start the diagnostic

procedure by verifying the customer com-plaint and checking for DTCs. However,technicians must first understand howDTCs are set and interpret what voltagesthe module should and is currently see-ing. Furthermore, the technician mustanalyze the circuit to verify if it utilizes aPU or PD resistor. The resistors willalways be on the signal side of the mod-ule, not the 5-volt reference or low-refer-ence side of the sensor. Variable resistive-type sensors with a low-reference wirewill utilize a PU resistor on the sensing

Figure 3

***Not Actual Values***

Figure 4



side. On the other hand, sensorswith a 5-volt reference wire, willutilize a PD resistor on the sens-ing side.

Diagnosing Switch InputsAll DTCs are set by certain mal-function conditions. Input switch-es, such as a brake pedal switch,normally experience the lowestand highest voltage parameters (0or source voltage). Most inputswitches can set two DTCs: switchcircuit low input (voltage) orswitch circuit high input (voltage).In addition, the module utilizes asystematic logic to set a DTCwhen certain conditions are met. For example, the brake pedal

should never be engaged for along period of time while thevehicle is accelerating. A P0719brake switch circuit low inputwould be set if the PCM sees 0volts at the brake switch inputfor a certain period of time whileaccelerating. This logic is pro-grammed into the module. The schematic on Figure 5

illustrates a basic brake switch

circuit that can be categorizedinto three sections: the compo-nents before the switch, after theswitch and the switch itself.Normally, 12 volts should befound at the PCM when thebrake pedal is disengaged. If 0volts is found at the brakeswitch, there might be an openbefore it, or a blown fuse causedby a short to ground in betweenthe PCM and the fuse. If thefuse is good, the next stepwould be to diagnose where theopen is located. A technician can test the resist-

ance of each component or wireto find the open, but that wouldtake some time to find everycomponent or connector. Itwould be more efficient to test atthe switch. After testing theresistance of the switch, a volt-meter can be used to verify thesection containing the open.Depending on the source of volt-age, the voltage before theswitch should be high. If so, thenthe open is between the switchand the module. The PCMshould only be suspected onceall three sections are verified.

Diagnosing VariableResistive-Type SensorsAs stated above, it is normal for amodule to measure or sense thehighest and lowest voltagethreshold for switch inputs. How-ever, unlike switch inputs, vari-able resistive-type sensors will seta DTC if the module senses thehighest or lowest voltage thresh-old within a certain period oftime (see Figure 6). Sensor circuithigh-voltage codes, such as aP0118 on an ECT sensor, will setif the PCM senses an output volt-age of 4.92 volts or more for atleast 2 seconds. This fault will

also cause the scan tool to indi-cate an extremely cold tempera-ture. In contrast, sensor circuitlow-voltage codes, such as aP0117 on an ECT sensor, will setif the PCM senses an output voltage of 0.08 volts or less for atleast 2 seconds. With a sensor circuit low-voltage code, the scantool will indicate an extremelyhot temperature. There are also conditional-type

codes that can be set, such as aP0128 cooling system malfunc-tion. These conditional-typecodes are set when the computersenses something illogical happening. The PCM is pro-grammed to infer that thecoolant temperature shouldincrease after a certain amountof engine running time. Utilizingthe IAT sensor and other drivingconditions, the PCM obtains anestimated engine coolant tem-perature. The cooling system

Figure 5

***Not Actual Resistance Values***


Figure 6


malfunction code is set if theactual and estimated coolanttemperatures are too far apart orif the actual temperature islower than the estimated tem-perature reading. This problemcan be caused by a stuck-openthermostat, sensor circuit faultor a defective ECT.As designed, the ECT will

increase in resistance as coolanttemperature decreases. Theincrease of resistance willincrease the voltage/electricalpressure built up before it. Withthis stated, only an open or anextremely high resistance cancause the PCM to sense 4.92volts or more and cause the scantool to indicate an extremely lowcoolant temperature reading (seeFigure 7). Although a DVOMcan be used to diagnose opensand high resistances in the cir-cuit, it’s more efficient to utilizethe scan tool and jumper termi-nals. Similar to the switch circuit

diagnostic procedures, it’simportant to categorize the sen-sor circuit into three sections: thewire before and after the sensor,and the sensor itself. There are four steps to isolate an

open or high resistance on sensorcircuits similar to the ECT:1. Unplug the sensor connector

and test the resistance of the

sensor. This also allows the tech-nician to isolate the sensor,wires and the PCM. The sensorshould be replaced if the resist-ance is overload (OL) or out ofspecification. 2. Use a terminal jumper lead

to short the sensing wire toground (see Figure 8 on page38). Due to the negative voltageon the sensing wire, the PCMshould sense a voltage less than0.08 volts and the scan tool willindicate an extremely hot tem-perature reading. If the scantool does not indicate anextremely hot temperaturereading, the fault is between thesensor and the PCM, see Figure9 on page 38 (circuit 2).3. If the scan tool indicated an

extremely hot temperature read-ing with the shorted sensingwire, the next step would be tojump the sensing and low-refer-ence wires together (see Figure10 on page 39). Similar togrounding the sensing wire, thevoltage should stay low and thescan tool should indicate anextremely hot temperature read-ing. But, if the scan tool reading



Figure 7


stays extremely cold, the fault is in the low-ref-erence side of the circuit, Figure 9 (circuit 3). 4. Once the sensor and wires are confirmed,

the only parts that could cause the fault are theterminal connections to the sensor or the PCM,Figure 9 (circuit 4).

One of the most misunderstood and often the

first to be stated fault is a short.A short to power on the sensingwire will cause a sensor circuitvoltage high DTC, and a short topower on the low-reference sidewill melt the wire or destroy themodule. On the other hand, onlya short to ground on the sensingwire or an internally shorted sen-sor will trigger a sensor circuitvoltage low DTC (see Figure 11).Both of these faults can be testedwith an ohmmeter. A techniciancan measure the resistance of thesensor to verify that the sensor iswithin specifications. But if a short to ground is sus-

pected, the technician should dis-connect the sensor and PCM con-nectors, insert a jumper terminalin the sensing wire connector ter-minal and test forresistance/continuity to ground.The ohmmeter should read OL.Again, it’s crucial that the PCMshould only be suspected after allof the three sections have beenthoroughly tested. A technician doesn’t need to

know everything about the inter-nals of a module. However, it’svery important for all technicians

Figure 8



to understand how the sensor circuit is designed,the normal voltage range of the sensor and theenabling conditions of any DTCs they are diagnosing.

» TechFeature



Figure 9

Figure 10

Figure 11



At the shop, I often hearthe bad side of every-thing. One day, a cus-

tomer started talking aboutbio-diesel and had nothinggood to say about the subject.As time went by (over thecourse of a period of years),there was still nothing promising to report aboutbio-fuels. This has been quite disappointing becauseI hoped that after a lot of time, money and researchwent into a bio-fuel program, that someone mighthave finally figured the process out. I decided tolook into the bio-fuels program to figure out thereal truth.

The bio-fuel issue really intrigued me when Iwas working on two particular Ford vehicles. Theengines in question were the 7.3L IDI diesels that

were used in Ford trucks up until 1994 when thePower Stroke was introduced. These trucks werevirtually identical, with roughly the same amountof miles and symptoms. The problem plaguingthe two trucks was that they both had just shutdown and would not run. After some diagnosis, I found that the injection

pumps on both trucks were strangely acting thesame way, yet they had two different owners.The injection pumps appeared as if they were

» TechTalk BIODIESEL

Biomass orBio Mess?

Problems Associatedwith ‘Home Brewed’Bio-DieselBy Bob McDonalddiesel specialist

This diesel injection pump has been subject to home-brewed bio-diesel. Notice the corrosion along with thenasty deposits and residue.



worn completely out, and simply would not makeany pressure to send to the injectors. If you crackedthe line at the injectors, the fuel would just barelydribble out. What’s odd is this type of injection pump failure is

not at all common on these engines. The injectionpumps have a “rotary” design that was manufac-tured by Stanadyne and when they start to fail, thereare generally “tell-tale” signs which alert the ownerthat something is wrong. You just don’t see thesepumps running down the road and suddenly dieunless something strange or major happens. It wasvery odd that both of these pumps had gone badwith the same symptoms at the same time. When an injection pump needs a rebuild, I’ll often

send the pump to Carolina Diesel, the Stanadyneremanufacturing facility in Charlotte, NC, locatedabout 70 miles away. When I sent these pumps to Carolina Diesel, they

immediately contacted me to ask what kind of fuelthese engines had been running. Since I wasn’t sure,

I took a sample out of the vehicles in question andall I could tell for certain was that I wasn’t 100% theywere running diesel. I cut the fuel filters open andfound that both of the filters from two differenttrucks were completely stopped up with some sortof brown “ooze.” The guys at Carolina Diesel toldme that the pumps were internally damaged andcorroded, literally eaten up from the use of bio-diesel. I asked how they knew that this was bio-diesel and they said that they see this happen quiteoften when someone tries to make their own fuel. As we talked, I recalled all the bad things that I

heard about bio-diesel. Were they universally true? Itwas sure starting to look that way until I realizedwhat he said: “This type of pump failure tends to happenwhen people try to make their own fuel.”I wanted to get to the bottom of things and find out

more about bio-diesel — this would be a great edu-cation for me if I could figure out the situation. InNorth Carolina, there are only certain counties thatoffer bio-diesel and none of them are close to me. So,


if there have been any ill effects from using bio-diesel, Ihave not heard about it because no one around me hadany access to the product.I recall that several years ago equipment manufactur-

ers, along with several auto makers, had undergonesome testing and stated that the use of bio-diesel wasapproved for use in their vehicles. So why would a man-ufacturer suggest that it would be fine to use a bio-fuel ifit was going to destroy major engine components? Bio-diesel is manufactured as a replacement fuel for

compression ignition engines and can be made fromthree different types of oil: plant oils (such as soybean,cottonseed or canola), recycled cooking greases, oils oranimal fat. You can’t typically run a vehicle on this typeof oil — to make these oils a bio-fuel, they have to bebroken down by a process known as transesterification.This is a process where the oils are reacted with alcohol(usually methanol) with a catalyst (generally sodiumhydroxide) to produce bio-diesel. When properlyrefined, they produce a byproduct — glycerin (sugar) —which then needs to be extracted.

» TechTalk


Bio-diesel is often used as a fuel for compres-sion ignition engines and can be made fromdifferent types of oils: plant oils (soybean,cottonseed or canola), recycled cookinggreases, oils or animal fat.



But these processes have to be handled throughsuper refining and filtering processes. In order for abio-fuel to be produced legally, it has to conform to aspecification known as ASTM D6751. ASTM D6751gives a specific guideline for proper refining of bio-diesel. The EPA will only register bio-diesel as fuel ifit is made to this specification. Bio-diesel is generally rated as a percentage, such as

B5. This means 5% bio-diesel is mixed with 95%petroleum fuel. There are many different blendsranging from 5% concentrations to 100%. The con-centration is generally rated for various applications.Most automotive manufacturers will allow a maxi-mum of a B20 blend for on-the-road vehicles. While conducting research, I located a facility

nearby that made bio-diesel. Foothills-Bio Energiesmakes a bio-diesel that meets ASTM D6751 specifications. Another thing I learned was that it is nearly

impossible to make bio-diesel at home, whichanswers the question of where the negative comments had come from.

Motor Fuel ‘Moonshiners’Without the proper refining through the transesterifi-cation process, there are a lot of by-products that getleft behind that will damage engine components.Even though there are machines that make bio-fuel,this doesn’t mean the result will be suitable for

vehicle use. The biggest problem faced by the‘home brewer’ is handling the methanol. When the oil undergoes the transesterification

process by the use of methanol, the methanol ulti-mately has to be removed. Unfortunately, this leavesbehind methanol, which causes corrosion and doeslittle for the cetane rating of the diesel fuel. This iswhere the engine damage comes from: improperrefining leads to many chemicals left behind. Andwhat about the glycerin? How does the home brewerextract all of that? Who wants sugar in their fuel?After all this, it must be remembered that bio-diesel

is a good fuel when properly refined. Studies haveshown that bio-diesel produces more energy thanpetroleum energy. Also, bio-diesel reduces green-house gas along with tail pipe emissions. Petroleumdiesel fuel combustion has always been toxic andcarcinogenic. By using a B20 blend, these toxins canbe reduced by 40%. When properly blended, bio-diesel will not cause

any serious side effects for a fuel system or compo-nents. In fact, because of the way it is made, it isactually going to clean your fuel system.Manufacturers recommend that the filters should bechanged quite frequently when first using a bio-diesel until all of the fuel system is cleaned out. Thesediment you may find in your filters after changingfrom petroleum diesel to bio-diesel is leftover residuefrom the petroleum diesel.

The B20 blend is most commonlyused, although sometimes in coolerclimates a blend of B5 is more com-mon. This is due to the fact that attemperatures below 39° F, B20 willstart to gel.Just be certain when using bio-fuel

to make sure that it is coming froma reliable source; make sure that theprocesses that were used to makethe bio-fuel conformed to the ASTMD6751 specification. As for the Ford trucks I was work-

ing on, I found out the fuel fromboth trucks had been home-brewed.So warn your customers to be care-ful, the money they save from tryingto beat the system will end up cost-ing them in the long run if the fuelis not properly refined.



» TechTips HONDA \ SUBARU This month is sponsored by:

Applies To:

2003 Accord V6 — All2004 Accord V6 2-door —From VIN 1HGCM8...4A000001 through1HGCM8... 4A024092

2004 Accord V6 4-door —From VIN 1HGCM6...4A000001 through1HGCM6...4A1 00943

If a customer complains oneof the above vehicle models isexperiencing excessive crank-ing or hard starting, there aretwo possible causes:1. Contamination in the fuel

pressure regulator causes theregulator to stick or intermit-tently stick, causing a delay infuel pressure at start-up.2. Exhaust gas backflow into

the intake manifold at engineshutdown may cause a poormixture of intake air and fuelat the next engine start-up.

Corrective Action:

Replace the fuel pressure regu-lator, if needed, and use theHDS to update the PGM-FI soft-ware in the ECM/PCM.Note: The 2004 Accords with-

in the following VIN rangesalready have an improved fuelpressure regulator. For thesevehicles, skip Diagnosis, andgo to step 10 of the RepairProcedure to update the PGM-FI software in the ECM/PCM:— VIN 1HGCM8...4A018621

through 1HGCM8...4A024092— VIN 1HGCM6...4A068600

through 1HGCM6...4A100943.

Parts/Tool Information:

Fuel Pressure Regulator: P/N16015-SDB-A00Fuel Pump Module Gasket

Set: P/N 17046-SDA-A30Fuel Sender Wrench: P/N

07AAA-S0XA100

Diagnosis:

1. Install a fuel pressuregauge. (Refer to steps 1 and 2on page 11-332 of the 2003-’06Accord V6 Service ManualSupplement, or online, enterkeyword Gauge Test, andselect Fuel Gauge Sending UnitTest [V6 Engine] from the list.)2. Start the engine, and let it

idle for 2 minutes.3. Turn off the engine. Check

the fuel pressure gauge.Pressure should be 380 to 430kpa (55 to 63 psi).4. Monitor the fuel pressure

reading. If the fuel pressurebleeds down quickly after theengine is turned off, go to theRepair Procedure. If the fuelpressure does not drop quick-ly, go to step 10 of the RepairProcedure to update the PGM-FI software.Note: There is no specification

for fuel pressure bleed rate.Many variables can affect fuelline pressure, such as the fuel

Honda Suffers from Hard Start/Long Crank Time

Software Information:

HDS Software Version: 2.004.004 or later, PGM-FI Software Versions or later.

Year Program ID Program Part Number2003 CA3150 37805-RCA-315

CA 3160 37805-RCA-316CAA060 37805-RCA-A06CAL060 37805-RCA-L06

2004 CAA250 37805-RCA-A25CAA750 37805-RCA-A75CAL250 37805-RCA-L25CAL750 37805-RCA-L75


pump and fuel injectors. A badregulator will lose most of thefuel pressure in the first few min-utes after shutting off the engine.

Repair Procedure:

1. Relieve the fuel pressure.2. Remove the fuel tank unit.3. Remove the fuel tank unit

from the case.— Disconnect the fuel tank

sending unit connector. SeeFigure 1.

— Release the three clips, andthen pull out the fuel tank unitfrom the case. See Figure 2. 4. Release the clips, then remove

the fuel pressure regulator mountfrom the fuel tank unit.5. Remove the clip, then remove

the fuel pressure regulator. Installthe new regulator with new O-rings. Reassemble the fuel tankunit.6. Place the new gasket onto the

tank body.7. Align the marks on the fuel

tank unit and the fuel tank. (See

page 11-327, step 11of the 2003-’06 AccordV6 Service ManualSupplement.) Installthe fuel tank unit intothe tank without dis-lodging the gasket.Using hand pressureonly, slide the fueltank unit into thetank until it is proper-ly seated.8. Using the fuel

sender wrench,torque the new fueltank locknut to 93 Nm (69 lb.-ft.).Note: Do not use the locknut toforce the pump into the tank.9. Reinstall all removed parts.10. Use the HDS to update the

PGM-FI software in theECM/PCM, using HDS version2.004.004 or later. To update thePGM-FI software, refer to servicebulletin 01-023, Updating ControlUnits/Modules.11. Do the idle learn procedure:— Make sure all electrical items

(A/C, audio unit, defogger,lights, etc.) are off.— Start the engine, and let it

warm up to its normal operatingtemperature (the cooling fanscycle twice).— Let the engine idle (throttle

closed and all electrical items off)for 10 minutes.12. Do the low-rpm CKP

pattern learn procedure:— Test-drive the vehicle on a

level road. With the A/T in sec-ond gear or the M/T in second orthird gear, decelerate (with thethrottle fully closed) from anengine speed of 2,500 rpm downto 1,000 rpm.— Stop the vehicle, and put the

transmission into park or neutral.Set the parking brake. Do notturn off the ignition.

13. Connect the HDS to theDLC, and check the status ofPULSER F/B LEARN:— On the Selection Menu, select

PGM-FI.— On the Mode Menu, select

Data List.— Check the value of PULSER

F/B LEARN.— If the value is Completed, go

to step 14.— If the value is Not

Completed, be sure the engine isat normal operating temperature(the ECT SENSOR [1] value is 176or higher), and repeat step 12.14. Do the high-rpm CKP pat-

tern learn:Note: The low-rpm CKP pattern

learn must be completed beforeyou do the high-rpm CKP patternlearn.— Test-drive the vehicle on a

level road. With the transmissionin first gear, decelerate (with thethrottle fully closed) from anengine speed of 5,000 rpm downto 3,000 rpm.— Stop the vehicle, and put the

transmission into park or neutral.Set the parking brake. Do notturn off the ignition.15. Connect the HDS to the

» TechTips HONDA

Figure 1

Figure 2

DLC (if not already connected),and check the status of PULSERF/B LEARN (HIGH RPM):— On the Selection Menu, select

PGM-FI.— On the Mode Menu, select

Data List.— Check the value of PULSER

F/B LEARN (HIGH RPM).

— If the value is Completed,you’ve completed the CKP pattern learn procedure.— If the value is Not

Completed, be sure the engine isat normal operating temperature(the ECT SENSOR [1] value is 176or higher), and repeat step 14.

16. Start the vehicle a coupletimes to make sure the symptomis repaired. If it is not, continuewith normal troubleshooting procedures for hard-starting problems.Courtesy of ALLDATA.

HONDA / SUBARU » TechTips

The Mitchell 1 Techline has heard of a very limited number of cases involving engine oil seals leaking afterbeing displaced from their normal positions. As the engine heats and cools, condensation can accumulate inthe PCV system, which, in extreme cold climates, can eventually turn to ice. Upon closer inspection, technicians have reported finding accumulations of ice restricting or blocking air-

flow through the PCV system. When the engine’s PCV system cannot “breathe” properly, excessivecrankcase pressure can build, resulting in oil seal displacement/leak. Once the seal is displaced, the pressure buildup condition is gone. This situation can easily be overlooked if

the vehicle is brought into the shop the night before inspection and/or repairs begin and allowed to “thawout.” Once thawed, the blockage is gone and the PCV system returns to operating normally. This conditionhas only been found to occur on turbocharged vehicles operating in extreme cold temperatures. Courtesy of Mitchell 1.

Mysterious Subaru Leaking Engine Oil Seals? Check the PCV!


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equipment supplier products in the original brand packaging have never been this accessible untilnow! Visit www.NAPAonline.com.Reader Service: Go to www.uhsRAPIDRESPONSE.com

Several popular Toyota, Honda, Subaru, Hyundai and Kia applica-tions will be among dozens of late-model import vehicles that arebeing added to Tenneco’s Walker line of catalytic converters in2013. The company also is significantly increasing its offering ofEPA- and CARB-compliant manifold converters to reflect the latestemissions control designs being used by global vehicle manufac-turers. Tenneco will introduce more than 40 additional converterpart numbers during the first quarter of 2013 and approximately120 new SKUs over the course of the year. Reader Service: Go to www.uhsRAPIDRESPONSE.com

Bosch’s newly expanded line ofmass air flow (MAF) sensors,with nearly 30 new part numbers, now features morethan 120 part numbers coveringpopular vehicles in operation inNorth America. This new cover-age, available through distribu-tion channels immediately, willhelp assure distributors and retailers that they will not misssales due to gaps in coverage.And this coverage will help assure repair shop owners andtechnicians that they can findthe OE-quality part they need,quickly and reliably, from theirregular supplier of Bosch products. Reader Service: Go towww.uhsRAPIDRESPONSE.com

Rislone introduces a full line ofsuper-concentrated fuel additives,packaged in six-ounce bottles fea-turing Rislone’s new patent-pend-ing EZ Nozzle delivery system thatworks on any vehicle, includingthose equipped with capless orobstructed fuel systems. The newline includes: Fuel Injector Cleanerwith Upper Cylinder Lubricant,Fuel Injector & Carb Cleaner, Octane Booster, Gas Treatment,Ethanol Fuel Treatment and Water Remover Fuel Dryer. 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 Airtex Corporation 5, 23ALLDATA 39APA Management Group 17Auto Value/Bumper to Bumper Cover 4BendPak 29Champion Spark Plugs/Federal-Mogul 12, 13Delphi Products & Service Solutions Cover 2, 1DENSO Sales California, Inc. 25Dipaco Inc. 43Federated Auto Parts 20, 21GAAS 35Hughes Engines, Inc. 44Jasper Engines & Transmissions 47King Electronics 36Mr. Gasket Performance Group 10NAPA 3NAPA Belden 15NGK Spark Plugs 11Nissan Motor Corp. USA Cover 3O'Reilly Auto Parts 27Parts Master 33Schaeffler Group USA 8, 9Spectra Premium Industries 41TechSmart SMP 19TYC/Genera Corp. 7WIX Filters 45

>> 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.

Post your job for just $50 a month!Visit AutoProJobs.com to get started today!

Contact: Karen Kaim p) 330.670.1234 ext. 295 f ) 330.670.7153 [email protected]


Reader Service: Go towww.uhsRapidResponse.com

WANT DETAILS ONTHE PRODUCTS & SERVICES YOU

SEE IN

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

ERIKSSON INDUSTRIES • 800-388-4418Old Saybrook, CT • FAX 860-395-0047 • www.zftranspart.com

Audi • BMW Jaguar • Porsche

Range Rover • VW

Filters Mechatronics

Kits Oils

Hard Parts Manuals

Torque Converters

Authorized Distributor

Transmissions/Parts




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.

AdvertisingRepresentatives

The Tech Group

Bobbie [email protected], ext. 238

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



The original 1966 TV Batmobile sold for $4.62 million at Barrett-

Jackson Auction Company’s Scottsdale Auction last month.

The original Batmobile started its life as the one and only 1955

Lincoln Futura concept car, which was heavily modified by George

Barris to become the Batmobile in the live-action TV series Batman,

as well as the movie adaptation, starring Adam West.

The auction tent was brimming with excitement as fans watched

the price for the Batmobile skyrocket to historic proportions on

the Barrett-Jackson auction block. Legendary customizer and

creator Barris looked on with pride from the auctioneer’s stand,

even adding his signature jacket to the sale, as the crowd cheered the auctioneer on.

The original Batmobile is now the highest selling car at the company’s annual Scottsdale Auction.

For more information about Barrett-Jackson auctions and classic vehicles, visit www.barrett-jackson.com.

» Test Drive

More than 160 racing teams have completed their two-minutevideo entries into the Champion spark plug brand’s $125,000“Search for a Champion” racing sponsorship contest, and it’snow time for consumers to choose their favorites by logging on,viewing and voting on the website.

Voting for the grand-prize winner will take place Feb. 22through March 24, with the $50,000 Search for a Championsponsorship being awarded by NASCAR Sprint Cup driver andChampion spokesperson Kevin Harvick on April 2, 2013.

For more information about the contest and “PerformanceDriven” Champion products, visit www.AlwaysaChampion.com.

‘Holy Car Fan, Batman’

‘Search for a Champion’ Racing Sponsorship Contest Narrows Finalists to 15

GUESS THE CAR! WIN $50!

Employees of Babcox Media, industry manufacturers and Underhood Service advertisers are not eligible to enter.

December Solution: Touareg (Volkswagen) Solved by: Gina Gaddis, office manager, Cecil’s Hi-TechAuto Care, Vacaville, CA

CONGRATULATIONS Gina!

What vehicle MAKE does the picture on the left represent? Submit your guess with our online contest form by visitingwww.UnderhoodService.com/guessthecar or scan the QRcode to the right with your smart phone.

The winner will be randomly selected from correctentries and awarded $50. Entries must bereceived by FEBRUARY 28, 2013.

#11

#10

Photo courtesy Barrett-Jackson/George Barris

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