underhood service

®A MAGAZINE

■ Extended Oil Change Intervals ■ A/C System Inspections ■ Gonzo’s Toolbox: Professionally Speaking

Reader Service: Go to www.uhsRAPIDRESPONSE.com

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 April 2013 | UnderhoodService.com

40A/C UpdateCompressor Inspection

When a customer comes in complaining that their vehicle’sA/C system is not working, theproblem can stem from a numberof things. And the best way tobegin any A/C repair as is with a thorough inspection of the components.

18

4032

32Teck TalkExtending Oil Change Intervals

Technical contributor Gary Gomsexplains that extended oil changeintervals can be a mixed blessing.On the upside, they help conserveoil and reduce carbon emissions.On the downside, many vehicleowners are forgetting to checktheir engine’s oil level between oilchanges — and risking damage.

TECH FEATURE: Hall Effect Sensor Diagnosis

DEPARTMENTS

6 Perspectives

8 Aftermarket Update

10 Directions

14 Around the Shop

46 Tech Tips

52 Shop

54 Rapid Response

55 Guess the Car

55 Classifieds

60 Gonzo’s Toolbox

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)

(April 2013, Volume XVIII, Number 4): 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. 260, 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.

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Classified Sales Tom [email protected], ext. 224


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

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Columns

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46

AUGMENTED REALITY CONTENT IN THIS ISSUE:

Publisher’s Perspectives 6Auto-Video Inc. 29 and 45Extending Oil Changes 38A/C Hose and Line Inspections 42


If not, don’t miss the excitement provided by Augmented Reality (AR) technology powered byAVI PLAY within the pages of Underhood Service. Once you’ve downloaded AVI PLAY, openthe App and hold your smart device over this page to unlock a special message from me.

We launched our AVI PLAY App last month, providing a seamless transition from the pages ofUnderhood Service to digital information on your mobile device in the form of video, 3-D imagingand other exciting types of content supported by AR.Are we heading down the right path? I believe we are, and so does Apple. Apple is quickly moving into Augmented Reality in an attempt to stay ahead of its customers’

expectations. They have identified Augmented Reality as a new content channel with a plethora ofapplications that includes education; we have a similar strategy in place. Each issue of Underhood Service will continue to include insightful technical features in print,

supplemented by relevant video content powered by AVI PLAY. And there’s more. Watch for ouradvertisers taking advantage of this technology by bringing an additional dimension to theiradvertising and promotional messaging.

Start now by downloading AVI PLAY by following these two easy steps:

Share your thoughts by contacting me at 330-670-1234ext. 280, or by e-mail at [email protected].

DID YOU EXPERIENCE THE MAGIC OF AVI PLAY IN THE LAST ISSUE?IF YOU HAVE, THANK YOU!

» Publisher’s Perspective By Jim Merle | PUBLISHER

Step 1: From your Apple or Androidsmart phone or tablet, visitwww.AVIplayApp.com to downloadAVI PLAY.

Step 2: Open the AVI PLAY App. Onceit’s downloaded, hold your device overthis page to unlock a special requestfrom me.


For free e-mail updates with the latest aftermarket news, tech tips and supplierpromotions, log on to AutoCarePro.com.

» Aftermarket UpdateBrought to you by:

Automotive Parts Associates’ (APA) 32nd annual Shareholders’ & Manu-facturers’ Conference, held March 14-16 in St. Augustine, FL, boasted 310people in attendance, building on the momentum of last year’s successfulevent. Serious about fueling their business success, the 66 members and74 vendors in attendance engaged in several networking opportunitiesand one-on-one meetings. The general session kicked off with opening comments by Dan

Freeman, APA president and CEO. Keynote speaker Tim Knox, sharedcommonsense business advice in the areas of customer service andleadership. Read more on the conference at: http://bit.ly/10eGRHw.

Veyance Technologies, Inc., manufacturer of Goodyear Engineered Prod-ucts, announces that Robert Ostrander of Mr. Fix It in Otter Lake, MI, isthe 2012 Goodyear Gatorback Club grand-prize winner.Ostrander received a $1,750 Snap-on Tools gift card, a $1,750 Visa

debit card and an array of Goodyear Engineered Products apparel andmerchandise.Ostrander has been a Gatorback Club Member for two years and was

thrilled to be named the 2012 grand-prize winner. To learn more aboutthe Gatorback Club and to sign up for rewards, visit:www.goodyearep.com/gatorbackclub.

It’s time to “Get Dirty with Kenny” and this year, Kenny Schrader isbringing along his friends, Kevin Byrd and Willie B., the hosts of theFederated-sponsored SPEED show “Two Guys Garage.” Kenny and theTwo Guys will be taping a special on-location episode of “Two GuysGarage” as Federated entertains the winners of this exclusive FederatedCar Care promotion. The annual “Get Dirty with Kenny” dirt track driving extravaganza

will again take place this year at the Federated Auto Parts I-55Raceway in Pevely, MO, outside of St. Louis. Winners of this FederatedCar Care promotion will receive the opportunity to race with NASCARdriver and dirt track legend Schrader as well as get a behind-the-sceneslook at the racing business. To be eligible to win a chance to “Get Dirtywith Kenny and the Two Guys,” a shop must be enrolled as aFederated Car Care Center member by June 1, 2013. To find out if youare up to the “dirty” challenge, visit www.federatedautoparts.com.

Tenneco has launched a new website for its Walker emissions controlbrand products that provides a wealth of valuable, timesaving diagnostictools and other important content designed specifically for automotiveprofessionals.The new WalkerExhaust.com features continuous access to compre-

hensive eCatalog tools through a highly visible new location along theleft side of the screen, as well as a convenient part search feature cover-ing the complete offering of Walker catalytic converters. Read more at:http://bit.ly/10j1XWo. ■

INDUSTRY NEWS...


Many of you readingthis have probablybumped elbows with

Al Duebber at one time or an-other. In fact, in the automotiveservice and repair industry, itwould almost be hard not to.Duebber, as you may know, is

the founder of Duebber’sAutomotive, a nine-bay auto-motive repair shop thatincludes a full-service gas sta-tion and convenient store inCincinnati, OH.In the past 40 years, Duebber

has been active in industryorganizations. He’s served asvice chairman for theAutomotive ServiceAssociation (ASA) and hasserved on the board of trusteesfor National AutomotiveTechnicians EducationFoundation (NATEF). He’s been ASE-certified as a

service consultant (level C1)and an Accredited AutomotiveManager through theAutomotive ManagementInstitute. And his shop, whichwon the 2004 CARQUESTExcellence Award, was one of

the first service centers in thecountry to be recognized byASE as a Blue Seal ofExcellence facility. Besides his service in various

automotive repair organiza-tions, Duebber also has servedas an advisory board memberfor Underhood Service since themagazine was founded back in1995.

Many of you know Duebberretired late last year, and hand-ed the reins over to his sonMarc. We’re proud to haveMarc continue the Duebber

tradition of serving on ouradvisory board that is used foradvice on article ideas andtrends in the industry, as wellas assistance in completing surveys or questionnaires aboutthe industry for our researchneeds.And, look for profiles of our

other helpful advisory boardmembers (listed on page 4) inupcoming issues of this maga-zine. We take this opportunityto thank them for their servicein providing content ideas thathelps us generate a beneficialmagazine to you, our readers.

Passing the AdvisoryBoard Torch

» Directions BY Edward Sunkin | EDITOR

You can read more about Marc andDuebber’s Automotive beginning onpage 14 in our “Around the Shop”column.

In case you missedits introduction inlast month’s issue,we are continuing

our exciting bonus AugmentedReality (AR) content throughoutthis issue with AVI PLAY.Using your smart device, (seedownload instructions to theright), you can view additionaltechnical content that comesalive at your fingertips.This AR content (listed on

page 4 of this issue) is pre-sented in short, informativeclips that we at UnderhoodService believe is next step inthe dissemination of technicaland instructional content toshop owners and technicians. Email us your ideas and

comments on AR at [email protected]. ■


If there’s one steady themerunning through 40 years ofbusiness at Duebber’s Auto-

motive in Cincinnati, OH, it’sstellar customer service. It’s thetradition passed from the originaltwo-bay shop founded in 1973, tothe eight-bay shop transitioned inDecember to the capable handsof current owner, Marc Duebber.Customer service, Duebber

says, is what he likes best aboutthe business. “Definitely, 100%, it is taking a

situation where somebody isdistraught and making that situ-ation better for them,” he said. When someone comes in with

a blown radiator hose, Duebbergets the car in, gets it fixed, anddelivers it to the customer’shome or work. “Whatever they need, it’s just a

matter of getting it taken care ofand making them happy. That’swhat we do best, no question.My goal is to equate to them‘you really don’t have a prob-lem, just a situation,” Duebber

says. “Like they say in Jamaica,no problem mon, just situation.”And to ease that situation,

Duebber’s offers pick up anddelivery service, early and late

pick-up and drop-off, and arental car for local driving whilethe vehicle is serviced. For customers working during

servicing, Duebber’s has freeWi-Fi, free drinks and even aprivate office available.In Cincinnati, you’d better

stand out from the crowd.“There’s probably 10 shops in a

five-mile radius from us,” hesaid. “It’s competitive.”He compares the competition

to that of banks. “They all do the same thing.

It’s just a matter of their level ofservice. That’s where we’re at,”he said.Technology and convenience

makes a difference in servingthose customers as well. “It’s crazy, but there are some

people I’ve never even talkedto.”With early and late drop-off

and pick-up, thanks toDuebber’s Carry Out, the con-venience store right next door tothe shop, the vehicle can be

» Around the Shop ADVISORY BOARD PROFILE

Customer Service is Key toLongevity for Duebber’s AutomotiveBy Cheryl McMullen, Contributing Writerwww.duebbersautomotive.com

Marc Duebber, owner

dropped off before the shopopens. The tech takes a look dur-ing work hours. But where oncehe showed the customer theirworn brake pads in person, nowit’s pictures on the iPhone by textor email.A lawyer in court or a teacher in

the classroom can’t take a phonecall, he says, but a text showingthe problem, the fix and the costdoes the trick. That’s how somecustomers want it: simple.But technology, too, can pose its

own headaches, Duebber said.“Technology keeps creeping in

to the business. The Internet hasbecome an absolute animal,” hesaid.A problem every shop faces is

people with access to partsonline. When Duebber tells a cus-tomer the final cost of service, thecustomer invariably brings up apart found on eBay at half price.Duebber does his best to explain. “I sell my service and warranty

first. Here’s what I’m giving you.And I’m going to 100% cover it,”he said. “You can’t pick up some steaks

at the butcher and take them ondown to Outback and have themcook them up,” he says. Still, thereare those who want to pick upthat eBay pump even if it’s non-returnable and not guaranteed. “I just say, ‘yes, you can buy

that part. But if that part fails,you’ll pay me to do that job againand you’ll pay me to take the partback off.’ We’re in the business tomake a profit.”

EDUCATIONOf course, state-of-the-art technol-ogy and equipment have helpedDuebber’s Automotive meet thechanging needs of customers. Butthat quality equipment doesn’t

mean much without top, educatedtechnicians. The shop, founded by Duebber’s

father, Al, celebrated 40 years inMarch. Duebber says he grew upin and around the shop since theage of 10. In December, Al retiredand transitioned the business tohis son. And if the emphasis oncustomer service was passed fromfather to son, so was the idea thateducation keeps technicians state-of-the-art as well.“Cars are changing. Technology

is changing,” Duebber says.“Let’s be the best at what we’redoing. The idea behind gettingASE certified, taking classes andcontinuing education is state-of-the-art.”

His team embraces the chal-lenge. Recently, Duebber tookthe entire shop to professionaltraining classes at an expo put onby an auto parts supplier inCincinnati.“We all went to different class-

es. I paid for the training, and Ipaid them to be there.” The team wants to improve as a

whole, because they want to bethe best.That’s a lesson young techs

coming up in the ranks can learn,Duebber says.“If you don’t have passion

about what you’re doing, I don’tcare what it is, it’s never gonnawork for ya. It’s all about passionand drive.” ■

» Around the Shop

UnderhoodService.com 17

Hall effect crankshaft position (CKP) andcamshaft position (CMP) sensors are crit-ical components of an engine manage-

ment system. The inputs they provide enable thepowertrain control module (PCM) to determineengine speed and position including where agiven cylinder is within the four-stroke cycle.Such information is vital to command ignitioncoils and fuel injectors in proper time and se-quence. The data from these sensors also is uti-lized for other important functions including fuelmetering, misfire detection, variable valve timing(VVT) control and more. Although two-wire variable reluctance sensors

producing an alternating current can still befound, the three-wire digital Hall effect sensor hasbecome the most prevalent type on late-modelvehicles. Despite such importance, CKP and CMPsensor diagnostics are often misunderstood. This

article will examine three-wire Halleffect CKP and CMP sensor opera-tion, function and diagnostics.Hall effect position sensors

contain a magnet and elec-tronic components, but, at asimple level, are switches.The switch is a transistorwithin the sensor. The func-tions of the three wires aresensor supply voltage, signalvoltage and ground. Unlike theirtwo-wire counterparts, Hall effectsensors require external power andground to function. The transistorwithin the sensor connects or dis-connects the signal circuit toground. Voltage on the signal circuitis provided by the PCM utilizing five


» TechFeature CRANK AND CAM SENSOR

Crank and Cam Position Sensor Operation, Function, and Diagnostics

By Matt Dixon, assistant professor, Southern Illinois University at Carbondale

or 12 volts. A small level of current is passed through a magnetic field within thesensor, which is altered by a revolving metallic tone ring. The actual Hall effect is achange in voltage in relation to the change in magnetic field. Hall effect voltage is processed using several electronic conditioning compo-

nents to switch the transistor base. The result on the signal circuit is a digitalhigh or low voltage signal. While positioned over a metallic section of tone

ring, the transistor is switched on, resulting in a low-voltage state.When over an air gap, the transistor is switched off, resulting in

a high-voltage signal state. A DVOM and a ferrous pieceof metal such as a feeler gauge can be used to test basic

functionality of a three-wire CKP or CMP sensor. SeeFigures 1 and 2.The tone ring provides a metallic pattern of slots

that rigidly connect to the crankshaft or camshaft(s).The tone ring for the crankshaft can be an externalplate located directly behind the harmonic balancer,be a part of the flexplate or flywheel, or bolted to thecrankshaft internally. Likewise, a camshaft tone ringcan be placed and attached using different methods.Location and placement choices have pros and cons.

For example, flexplates can crack around the centersection often without the expected noise or other symp-

toms. Such a crack can shift the outer section contain-ing the tone ring slots. This has a dramatic impacton timing and results in noticeable driveabilityissues. See Figure 3 on page 20. The trend over time has been an increasing number

of slots in the tone ring pattern. Each slot provides anengine position pulse to the PCM. Additional slots provide

improved timing precision and misfire detection. Often a CKP signature notch orgroups of notches allow the PCM to quickly identify companion cylinders. SeeFigure 4 on page 20.


» TechFeature

Figures 1 and 2: Voltmeter monitoring the CMP sensor signal wire. The ignitionis in the run position. As the metallic feeler passes under the sensor, signal volt-age is pulled low by the sensor. When the feeler gauge is moved away, voltageremains at the 5 volts provided by the PCM.


As the engine revolves, theCMP pattern enables the PCMto synchronize crank andcamshafts and determinewhich cylinder is on whichstroke. Unique signature pat-terns afford some engines thecapability to start even if aCKP or CMP sensor fails.Other engines will not start atall. If the engine does start ononly one sensor, it may experi-ence long crank time, reducedpower output, lower rpm lim-its and an illuminated MIL. Tone ring patterns can

change between model yearson the same engine. SeeFigure 5 on page 22. This isimportant when consideringinstallation of used or remanu-factured engines or parts. Thiscan be more difficult to visual-ly catch than one might think.Incompatibility between CKPand CMP tone rings or thePCM family can result in a nostart. The number of CKP slots per

unit of time provides the rpmvalue. Rpm value is used formany items beyond thetachometer and rev limiter,including fuel pump relaycontrol strategy. If the rpmvalue is lost, the PCM is programmed to de-energize

this relay. Rpm is also anoften-overlooked value in loadcalculation. Fuel injection sys-tems determine airflow basedoff of either rpm and mass air-flow signal or rpm and mani-fold absolute pressure values.Correct air mass per unit oftime is essential for accurateinjector pulsewidth. Enginerpm can also be comparedwith transmission input shaftspeed to verify torque convert-er lock up.Crankshaft position is used

for timing functions includinginjector firing. Port injectionsystems typically pulse injec-tors during the exhaust stroke.Gasoline direct injection sys-tems pulse on the intake orcompression stroke dependingon operating mode. Pulsinginjectors on the wrong stroke

Go to www.uhsRAPIDRESPONSE.com

Figure 4: The tone ring can bea part of the flexplate. Thisflexplate features signaturenotches to quickly identifyengine position.

Figure 3: Upon closeinspection of this flex-plate, a crack can be seenforming around the centersection of the plate. Oncethe crack makes it all theway around, actual crankposition in the center canshift compared to the out-side. If the CKP tone ringis utilized on the outerportion of the flexplate,measured crankshaft posi-tion will be incorrect.


can result in increased emissionsand power loss. Base ignitiontiming and spark advance eachdepend on accurate position cal-culation. An important sparkadvance input, the knock sensor,may only be monitored duringcertain degrees of crankshaftrotation. With camshaft phaserVVT, the CMP to CKP relation-ship is used to determine ifadvance or retard commands

have been carried out. A mal-function or slow operating sys-tem results in degrees of varianceand a possible DTC. Crank posi-tion and acceleration is also usedto detect misfire. When eachcylinder is “up to bat” on thepower stroke, the PCM expects tosee an acceleration in crankshaftspeed. A lack of acceleration iscounted as a “strike” or misfire.Enough misses in a group of rev-

olutions result in a misfire code.See Figure 6 on page 24.There is one new function to

mention. Engine start-stop tech-nology is appearing on conven-tional gasoline-powered vehiclesto improve fuel efficiency. Whenthe PCM determines conditionsare suitable for automaticengine shutdown, the PCMclosely monitors and logs theCKP pattern. Crankshafts usuallystop in one of a few placesdepending on number of cylin-ders. As the crankshaft comes toa rest there is no guarantee thatit will only rotate in its normaldirection. Up until now, it wasunnecessary to ever think aboutmonitoring for reverse rotation.However, with automaticrestart, it’s imperative to logexact crankshaft position for arapid and seamless start. BothCKP and CMP patterns are uti-lized along with upgraded PCMsoftware to accurately log shut-down crankshaft position. PCM, CKP and CMP sensor

diagnostics can be confusing.Unlike a typical five-volt enginecoolant temperature sensor, CKPand CMP sensors utilize the endsof the voltage spectrum during



Figures 5a and b: Be careful of changing patterns even on the same engine year to year. These are bothDodge 2.7L V6 CKP and CMP scope patterns. The left (a) was taken from a 2001 model and the right (b)from a 2008. Though the crank pattern is obviously different and perhaps easy to spot, take a look at thecam pattern. The left has a slot code pattern of 1-2-3-1-3-2 while the right is 1-3-1-2-3-2. This is importantto consider during engine or head replacement using different parts.



normal operation. There is noway to reserve a section for voltstoo low or too high types of fail-ures. Instead, rationality isemployed using a “tattletale”method. If either the CKP or aCMP sensor reports a togglingvoltage pattern while the other(s)

do not, the opposite sensor(s)are deemed to be inoperative. P0335 no crank signal and

P0340 no cam signal codes areset this way. Such rationalitysounds simple enough butsometimes the PCM can be“tricked” into declaring the

wrong failure. This is more likelyduring an intermittent failure.Failures such as P0339 intermit-tent crank signal failure can bedownright perplexing. Also, ifneither CKP nor CMP sensors arefunctioning, it is possible toencounter a no start without anycodes. It should be mentionedthat CKP and CMP sensors oftenshare a PCM supply voltage anda sensor ground. See Figure 7. A

Figure 6: Honda scan tool screen shotshowing misfire counters. Engine miss-es are detected by the PCM usingcrankshaft acceleration or lack of it asmeasured by the crank position sensor.Such data is helpful in detecting missesor verifying a repair even without acorresponding code.

Figure 7: CKP and CMP sensorsoften share supply voltage andsensor ground with each otherand other sensors. An open orshort in a shared circuit canbring multiple sensors to a halt.



short in one sensor can bring down all sensors on asupply voltage circuit as can a sensor ground open.Monitoring key-on sensor supply voltage is a logicalstep during a no start. If sensor voltage is not detect-ed, checks need to be repeated with different sensorsdisconnected. Whether diagnosing a CKP or CMP sensor code,

no start or other driveability issue, a two- or morechannel oscilloscope is a powerful tool. Manyscopes feature a recording function that is extreme-ly helpful in catching glitches. One reason for thisis the extremely large number of switches. If a CKPtone ring has 34 slots and the engine spins at 2500rpm, then 85,000 slots pass by per minute. A glitchis sure to be felt in vehicle operation, but no othertool is likely to catch it. The scope is also valuable in determining correct

camshaft timing. Just a few degrees of CKP to CMP

variance can result in codes and driveability issues.Without a known-good picture, it’s difficult to inter-pret the image with complete confidence. Onlineresources such as the International AutomotiveTechnicians Network (iATN.net) feature a waveformdatabase that can be helpful. Deciding to tear into anengine for a suspected cracked flexplate or shearedoff cam to sprocket dowel pin is easier done with aknown-bad pattern. While scope images can save time compared with

component disassembly, scope hook up is best per-formed using the easiest access point. Some vehicleshave a starter, manifold or other obstacle in the wayof sensors. In such cases, the PCM is an easier accesspoint. See Figures 8 and 9. Obtaining an accurateconnector pin out is necessary to tap into a sensorsignal at the PCM. Care needs to be taken with frag-ile connector covers and while backprobing the cir-cuit. Terminal inspection and wiggle tests are legiti-mate, but collateral damage resulting from roughhandling is best avoided. Scan tools have mixed value for CKP/CMP sen-

sors. CKP/CMP variance can be a helpful value inspotting timing chain stretch or related componentwear. Many tools also offer a crank/cam relearn fea-ture. Though the specifics of this procedure canvary, it generally resets a correlation value in thePCM. Service procedures often call for a relearn afterreplacing sensors, timing chain/belts, tensioners orresetting cam timing. The relearn procedure may benecessary for the misfire monitor and may requiredriving the vehicle. Somewhat less helpful if notdeceptive are datastream values such as CKP andCMP present/not present or SYNC true/false. Ihave experimented with intermittently interruptingand manipulating CKP/CMP signals while

Figure 8: This 2012 Chrysler 300 6.4L V8 CKP sensor is revealed after the underbelly AERO shield andstarter removal. Luckily there is an easier way to monitor it.

Figure 9: The easier way. After removing a fewtrim clips, the cowl can be pulled back to accessthe PCM on the 300C. The PCM is often but notalways the easier choice in getting to the CKPor CMP signals.

» TechFeature


monitoring such PIDs. The scanner sometimes catches it. Scan tools convert serial data and, depend-ing on the specific tool and number of PIDs beingviewed, the update rate may not be nearly fastenough. These sensors are normally very reliable, however,

they do occasionally fail without good explanation.Heat, vibration and mechanical shock are plausiblesuspects for the sensor, while wiring issues, termi-nal spread and occasional PCM issues account forremaining circuitry. Some sensors last hundreds of thousands of miles

while some fail right out of the box. When replacing a sensor, first be careful not to drop

it as the magnet or internal electronics can be damaged. Also, follow instructions in regard to airgap. It is typically not adjustable, but be sure mount-ing surfaces are clean and fasteners are properlytorqued. Some sensors come with a sticker on theend that gets removed as the tone ring spins. I havetested increase of air gap using shims and found

signal failure in as little as 0.100”. Without a doubt,CKP and CMP sensors collect vital information forthe PCM. When one or more fail to operate, your cus-tomer will know there’s a problem. As the big wheelkeeps on spinning around, hopefully you’re ready totest these sensors to get the lowdown on why andkeep customer satisfaction switched on high. ■



Auto manufacturers, in general, are contin-uing to reduce vehicle maintenance re-quirements by extending oil change

intervals. But extended oil change intervals are amixed blessing. On the upside, extended oilchange intervals are conserving precious oil andreducing carbon emissions. On the downside,many vehicle owners are forgetting to check theirengine’s oil level between oil changes.The most common result is an engine ruined

by excess accumulations of varnish and sludgedue to using motor oils that are not approvedby the engine manufacturer. In less commoninstances, the engine fails due to low engine oillevels and a subsequent lack of lubrication.Whatever the case, extended oil change intervalsare changing how we should recommend andperform scheduled vehicle maintenances.

Sensing LevelsThe oil level sensor obviously warns the driverwhen the engine oil level is critically low.Although many auto manufacturers install oillevel warning systems as standard equipment,many vehicles in the current fleet aren’t soequipped. In other instances, the oil level sensor

might not function correctly.Consequently, it’s always important for the

technician to check the engine’s oil level when-ever the vehicle is being serviced. If the oilappears very dirty or the oil change interval hasnearly expired, an oil change and scheduledservice recommendation should be made. If the oil appears clean but the level is low, it’s

important to know the vehicle owner’s brandpreference for engine oil before adding oil. Mostwon’t know or care, but some owners mightprefer using a specific brand of oil. In any case,if the engine oil level is low, always inspect theengine and oil filter for leakage or other signs ofoil consumption and make the appropriate service recommendations.

Monitoring Oil LifeModern oil life monitors use data from thePowertrain Control Module (PCM), such as calculated engine load, trip length, averageoperating temperature, etc., to measure oil life.It’s not unusual for oil life monitors to extend oilchange intervals to 10,000 or more miles.The primary issue in dealing with oil life

monitors is to ensure that the replacement

» TechTalk OI L

By Gary Goms, technical contributor

engine oil meets the manufacturer’s extendedmileage requirements. The “generic” 5w-30 oilmight, for example, expire at 6,000 miles becauseneither the base oil nor the additive packagemeets original equipment (OE) requirements,which results in disastrous consequences. In a few situations, the oil life monitor might not

accurately indicate expected oil life. The evidencemight be a varnish or sludge accumulation on inter-nal engine parts. Valve train sludge, for example,can often be observed when the engine oil cap is removed for service. Similarly, rust, varnish andsludge can form on the upper portions of the oildipstick. If varnishing or sludging is apparent, ashorter oil change interval should be recommended.

Controlling DepositsWhile lead-free, high-detergent gasoline has dra-matically reduced intake port and combustionchamber deposits, modern engine oils are also spe-cially formulated to prevent carbon from formingin the combustion chamber, piston rings fromsticking and oil additives from contaminating thecatalytic converter. In particular, modern engines generally use nar-

row, low-tension piston rings that are fitted verytightly into the piston to increase piston ring seal-ing and reduce oil consumption. On the upside,low piston ring tension reduces rotating frictionand cylinder wear. On the downside, low-tensionrings with tight side-gap clearances tend to stickwhen the incorrect engine oil is used. Therefore,the ability of an engine oil to clean and lubricatethe piston ring package is critical.

» TechTalk


Filter replacement intervals are designed to mini-mize maintenance expense for the vehicle owner. Photo courtesy of WIX Filters

» TechTalk OI L


Anti-Scuffing IssuesOil suppliers have also eliminated zinc and phos-phorous-based anti-scuff additives that reduce catalytic converter efficiency. While the eliminationof these particular anti-scuff additives hasincreased camshaft wear on some high-perform-ance pushrod-style engines, it hasn’t affected over-head camshaft engines due to the lower valvespring pressures used on overhead camshaftdesigns.On the other hand, some engines equipped with

direct fuel injection require a high degree of anti-scuff protection to prevent the camshaft-drivenhigh-pressure fuel pump and camshaft lobe fromwearing out. In most cases, oil refiners have goneto much higher quality base oils to prevent wearon the high-pressure fuel pump and cam lobe.Again, it’s vitally important to make sure that thereplacement oil is either OE oil or is approved bythe OE manufacturer.As for older, performance pushrod, flat-tappet

engines that are not equipped with catalytic con-verters, specially branded performance oils areavailable with anti-scuff additives to preventcamshaft and valve lifter wear. In addition, zinc-based “ZDDP” additives are also available toenhance the anti-scuff qualities of over-the-count-er motor oils. Again, these oils and additives arenot intended for vehicles equipped with catalyticconverters.

Causes of SludgingNeglected oil change intervalscan ruin the best engine oils. Asengine oil accumulates miles, itbecomes contaminated with car-bon, water and various acids, allof which are a by-product ofinternal combustion and whichwill form a film of black, gooeysludge on the interior parts ofthe engine.Cold-engine operation acceler-

ates the formation of sludgebecause the oil temperaturesaren’t sufficient to evaporateaccumulated moisture. Oilsludging is also aggravated byshort-trip, cold-weather drivingand by thermostats that are stuckopen. See Photo 1 on page 36.When the engine is operated at

high speeds and temperatures,sludge often dislodges and clogsthe oil filter. Since most oil fil-ters incorporate bypass valvesthat allow the lubricating oil toflow around a clogged filtermedia, the dirty oil can pass

OIL FILTER MAINTENANCE TIP:When installing the O-ring, it must be lubri-cated with clean, new engine oil.

The new O-ring must be installed with new,clean engine oil to allow it to roll smoothlyacross the sealing surface and preventingshearing, cutting, tearing or displacement outof its groove. Lubing the O-ring reduces theforce required for installation and acts as asafety check to ensure there is an O-ring inits intended groove. Dirty oil can have dirt,grit or metal particles that would not allowthe O-ring to move smoothly to its intendedgroove. Source: WIX Filters


» TechTalk OI L


directly into the engine and clogsmall-diameter oil galleries.

Getting DirtyIn any case, heavily sludged oilwill eventually clog the engine’soil pump pickup screen, oil filterand oil galleries. The initialsymptoms of oil starvation areengines that become noisy dur-ing cold start-up and oil pressuregauges that rise very slowly.Broken timing belts are alsosymptomatic of oil starvation onoverhead camshafts. Because thedamage usually includes thecrankshaft and piston assemblies,don’t be too eager to quote acylinder head replacement as thecure for a seized camshaft. SeePhoto 2.

All too often, the detergentscontained in fresh oil will accel-erate the clogging of oil pumpscreens and oil filters by loosen-ing accumulated sludge.Volumes of engine sludge anddirty engine oil also easily clogtoday’s compact oil filters. If theoil filter bypass valve opens dur-ing cold starts, more sludge anddirt will pass into the enginebearings and reciprocating parts.In addition, engine life is drasti-cally shortened when operated atextreme loads and temperatureswith badly degraded engine oil.See Photo 3 on page 38.The problem with any heavily

sludged engine is that internalrepairs tend to dislodge evenmore sludge into the oil stream.Because attempting to clean anengine in-chassis is both expen-sive and risky, you can best address the situation by replac-ing or rebuilding the engine.

Interference with VVTMost modern engines are verysusceptible to lubrication prob-lems because they are equippedwith variable valve timing (VVT).

Photo 1: While the slightly varnished interior of thisengine is normal, the varnishmight not have accumulated ifthe oil change intervals hadbeen shortened.


Photo 2: A loss of lubricationquickly scores pistons andother vital engine components.

OIL FILTER MAINTENANCE TIP: An efficient tool to add to anytoolbox for ensuring a spin-onoil filter is tightened properlyis a silver Sharpie marker.

When an oil filter is spun onthe engine until gasket contact,mark the filter at 12 o’clock witha Sharpie and finish tighteningper the filter’s instructions. Withthe mark, you will know exactlyhow far you’ve turned the filter,thereby helping prevent over-tightening or under-tightening.

Source: WIX Filters

» TechTalk OI L


A pulse-modulated control valve that meters oilpressure to a hydraulic piston or vane-typecamshaft timing phaser controls the amount ofadvance or retard. A separate valve-timing sensoris used to monitor VVT position.Quite clearly, the phaser must react to small

changes in oil pressure. Since sludge can interferewith the smooth modulation of the oil pressurecontained inside the cam phaser, the result can bepoor engine performance at specific engine speedsand loads. In many cases, a DTC will be storedthat indicates a problem in the VVT system.

Adding it All Up Since oil prices have climbed dramatically the pastfew years, customers are becoming more price- sensitive. But it’s also important to understandthat, to remain profitable, a shop’s pricing struc-ture for modern vehicle oil change and inspectionintervals must be realistic.In addition, you’re doing a disservice to your

customers if you’re exclusively selling low-costgeneric engine oils and budget-priced oil filters tomeet price-sensitive competition.OE-specification oils and filters often become

the cheaper (and wiser) choice when weighedagainst a costly engine replacement. If you do themath, it will become clear to you and your customer that using the correct engine oil and filter is the less expensive and far more prudentchoice. ■

Photo 3: Oil filter cutters are handy fordetecting metallic debris trapped in the oil filtering media. The duct tape helps the filterwrench grip the filter canister.

TAXICAB CONFESSIONSIf you find you have customers who often go beyond theOE-recommended conventional oil change interval fortheir vehicle, you may want to suggest to them moving toa synthetic oil.In an effort to demonstrate the performance of its syn-

thetic motor oil in severe service, one manufacturer con-ducted a field test using Las Vegas taxis. The combinationof continuous severe-service operation and challengingambient conditions created the ideal scenario for sludgeformation and catastrophic component wear.


» TechTalkThe oil manufacturer reported its syn-

thetic motor oil was used in six vehi-cles, representative of a typical taxifleet. During the 18 months, motor oilwas changed every 15,000 miles. Usedoil samples were drawn according to adefined, repeatable process and ana-lyzed on a routine basis.The test vehicles operated up to 24

consecutive hours each day, with theengine shut down only during refuelingor personnel changes. Excessive timeidling combined with stop-and-go driv-ing loaded with passengers and cargocharacterized typical driving conditions.Average speed over the course of the18 months in service was 14.6 mph,illustrating the severity of service.During summer months, ambient temperatures often exceeded 100º F,further increasing severity.

After accumulating 100,000 miles ofservice, one of the test vehicles — a2010 Dodge Charger — was removedfrom the fleet for inspection. TheCharger was randomly selected forteardown and analysis. The engine andparts were rated for sludge, wear andother distress by an independent

calibrated rater according to the criterion given in the appropriateCoordinating Research Council manual.The company reported that its oil

demonstrated superior ability to guardagainst the formation of sludge, withthe oil pan earning a high rating. Theoil screen was free of sludge anddeposits, proving the oil’s ability toprovide increased protection in severeservice while practicing extended drainintervals.Following 7,033 hours of operating

using the synthetic motor oil, theCharger’s cylinder heads (seen here)earned high ratings and demonstratedsuperior cleanliness. The varnish thatdid appear was considered normal tolow levels for this engine, despite thechallenging operating conditions. ■Source: AMSOIL

Confessions Continued


When a customer comes in complainingthat their vehicle’s A/C system is work-ing improperly, the problem can stem

from a number of things. And the best way tobegin any A/C repair is with a thorough inspec-tion of the components.

After checking components like the belts, thehoses and the related connections, the next stepis a visual inspection of the A/C compressor. This can be challenging sometimes because on

some vehicles they can be well hidden. So what do you want to look for? Well, you

need to check for any oil leakage and inspect theclutch and the bearing for good condition.Note: To perform detailed inspections, you

might want to look into acquiring a flexible auto-motive inspection-type mirror to allow you tosee into some of those tight spots and find outwhat’s going on in any particular area.Next, check the compressor clutch itself. You’ll

find that there’s an air gap between the compres-sor clutch and the bearing face. Inspect thatclutch air gap for its recommended spacing. To measure the air gap, you need to slide a gap

gauge between the compressor clutch and thebearing face. Verify that it’s not thinner than

0.014” and not greater than 0.030”.

MONEY TESTIf you discover that you just need to do a quickgap test and you don’t have access to service in-formation, try a money test. It’s an old rule of thumb using a nickel and

dime. The dime can be used for the minimummeasurement. If the air gap is thinner than adime, it’s too thin. Use a nickel to measure themaximum thickness. If you find that the nickeleasily slides in and out of the air gap, you canbet that the clutch is totally worn out. While this is a simple, quick test, to get the best

results, you always want to use the appropriateservice information and check it the way the carmanufacturer would want you to do it.

HOSE CONCERNSOne concern techs have is the issue of replacingA/C hoses following a compressor failure.Metallic debris that is spewed into the A/C

system when a compressor fails can block orificetubes and possibly damage a new compressorwhen it is installed. Getting all of the debris out of the system is

» A/C Update CLUTCH PROBLEMS

COMPRESSOR INSPECTION MAY LEAD TO WORN CLUTCH PROBLEMBy Underhood Service and AVI staff

therefore essential to make sure the new compres-sor won’t suffer the same fate. While most of the garbage ends up in the con-

denser, some can migrate from here to other partsof the system or be thrown backward into the suc-tion hose from the compressor’s intake port. Serpentine-style condensers with large diameter

tubes can usually be cleaned by flushing with anapproved flushing chemical. But parallel-flow con-densers or those with very small tubes may beimpossible to clean, requiring replacement to elimi-nate possible contaminants.As for the refrigerant hoses, replacing the suction

and discharge hoses should not be necessary, pro-vided they can be thoroughly flushed and cleaned.Hoses that contain mufflers or orifice tubes, howev-er, usually cannot be cleaned and must be replaced.

Installing a protective screen in the end of the suc-tion hose that attaches to the compressor and/orinstalling an inline filter to trap any residual debristhat may have been missed also is recommended foradded insurance against a future compressor failure.The suction hose is located is between the evapora-

tor and condenser. The high-pressure hose is between the compressor

and condenser. Late-model vehicles with R-134aA/C systems require “barrier” (nylon lined) hoseswith crimped end fittings. Older (1994 and earlier)vehicles with R-12 systems can use unlined hoseswith barbed end connections.When replacing A/C hoses, always use new O-

rings or seals.

CHECK THE RADIATORFollowing an inspection of a compressor clutch andcompressor that appear to be in good condition,check the front of the condenser for any type of airflow or debris, or anything that would restrict theability of the air to flow through the condenser andinto the radiator.

» A/C Update


IN THE CLUTCHBelt-driven compressors have a magnetic clutchon the input shaft that cycles the compressor onand off to control cooling. If needed, the clutchcan be replaced separately. If the compressor hasfailed, the replacement unit may or may not comewith a new clutch installed. We recommend order-ing a new clutch if one is not included.

» A/C Update


A suitable shop light should be used to visuallyinspect the radiator and condenser.On most vehicles, you’ll need to remove the plas-

tic cowl on the front of the radiator and then lookdown in between the components.Consequently, any vehicle with more than 100,000

miles on the radiator is a perfect candidate for aradiator inspection and evaluation. If the coolant isexcessively rusty or the radiator core is excessivelydamaged from road debris, it’s time to considerreplacing the radiator.

Tech Tip: Continued Inspection — How toSpot the Type of Refrigerant Leak for an

Accurate DiagnosisWhen diagnosing a refrigerant leak, it’s helpful to

know what type of leak is present in the air condi-tioning system. There are two types of refrigerantleaks — active and passive. An active leak is easi-er to locate than a passive leak. Knowing the typeof leak you’re dealing with will help determine thetype of refrigerant leak detection tool to use forlocating the leak.

ACTIVE REFRIGERANT LEAKThe active refrigerant leak is a continuous leak.

Using an electronic leak detector is an effective toolto locate an active leak. There are a number of common causes for active

leaks in an A/C system that include:• Corrosion porosity on a refrigerant line,

evaporator or condenserNote: Paint flaking from a steel refrigerant line or

condenser is not always an indicator of a refriger-ant leak. Paint flaking is normal and it will occurover time. Evidence of oil around the rusted orpaint-flaked refrigerant line does, however, indicatethat a leak is present.• O-ring or sealing washer

- Debris trapped between an O-ring or sealingwasher joint or mating surface.

- An incorrect size O-ring or sealing washerused on a joint or mating surface.

- A rolled O-ring.- A missing O-ring or sealing washer.

• Refrigerant line- Damage from bending a line during a refriger-

ant system repair.- An impact that caused the line to become

deformed.• Improperly torqued components

- An over- or undertorqued refrigerant line orcomponent joint or component fitting.

- An under-torqued pressure switch or cyclingswitch.

- A loose service port cap

Corrosion buildup around the O-ring and metal linedegradation at the O-ring may be the source of arefrigerant leak. Source: Delphi Product & Service Solutions

Did You Know… Most compressor failures arecaused by loss of lubricant and/or refrigerant.Repeat failures are usually due to system contamination (sludge or metallic particles froma previous compressor failure).


• Compressor- A crack in the compressor

housing.- Loose compressor through

bolts.- Compressor shaft seal.- Compressor body seals.

• Service valve or pressureswitch

- A pintle that is off center andis not seating properly

- A loose valve pintle• Component casting porosity

- Porosity from an improperlymanufactured part, such as thecompressor housing or a thermalexpansion valve (TXV) body.

PASSIVE REFRIGERANT LEAKA passive leak is a type of refriger-ant leak that occurs intermittently.Passive refrigerant leaks arecaused by changes in pressure,temperature or vibration. Since this type of leak is inter-

mittent, the use of the electronicleak detector may not be effec-tive; therefore, theuse of refrigerantultraviolet leakdetection dye willbe more effectiveat finding theleak. Once the dye is

added to therefrigerant system,it may requiretime to locate theleak, dependingupon the severityof the leak and the

driving habits of your customer.This could take from a few min-utes to a few days. Some air con-ditioning systems have dyeinstalled from the vehicle manu-facturer. Check before addingadditional dye to the system.The following are some examples

of how a passive leak can occur:• Pressure

- Expansion and contraction ofan under-torqued refrigerant line,component joint or componentfitting during operation of the airconditioner.

- Compressor shaft seal leak.• Vibration

- A cracked braze on a condenser or evaporator from arefrigerant line that is not supported properly.• Temperature

- Compressor body or fronthead O-ring.Source: Delphi Product & Service

Solutions ■

An impact to the refrigerant line resulted in this pinhole leak.

» A/C Update CLUTCH PROBLEMS


» TechTips Mazda \ Nissan \ Dodge \ Chrysler

Applies To:2003-’06 Mazda6 vehicles equipped with

manual air conditioning systemSome vehicles may experience an air selector

mode switch that will not switch into recircula-tion mode. This condition may be caused by alack of continuity in the mode switch.

Repair Procedure:1. Verify the customer’s concern.2. Record the customer’s pre-set radio stations.3. Disconnect the negative battery cable.4. Remove the climate control unit assembly.

See Figure 1. 5. Replace the mode switch with a modified

part. See Figure 2. 6. Reinstall the climate control unit assembly.7. Reconnect the negative battery cable.

8. Re-enter the customer’s pre-set radio stations.9. For 2006 models only: Perform the “Power

Window Initialization Procedure.”10. Verify the repair.

Power Window InitializationProcedure:1. Turn the ignition to the On position.2. From the driver’s seat, ensure the window

lockout switch is not depressed. See Figure 3. 3. Press the window switch down to fully

open the door window.4. Pull the window switch up to fully close

the door window; hold the switch up for twoseconds and then release it.5. Move to the front passenger seat and repeat

steps 3 and 4 on the passenger window switch.6. Verify the proper window operation using

each door switch.Courtesy of Mitchell 1.

Mazda Air Intake Selector Mode Switch Failure

Figure 1

Figure 2

Figure 3

This month is sponsored by:



» TechTips NISSAN

Nissan & Infiniti Dual Mass Flywheel Installation

Figure 4

Figure 6Figure 5

APPLIES TO:

2003-’07 Nissan 350Z 3.5L

2008-’12 Nissan 370Z 3.7L

2002-’06 Nissan Altima, Maxima 3.5L

2005-’12 Nissan Xterra, Frontier 4.0L

2003-’07 Infiniti G35 3.5L

2008-’12 Infiniti G37 3.7L

Today’s vehicles are becomingmore and more complex to service,so proper procedures are very im-portant to follow when making re-pairs. This is especially true whenworking on Infiniti and Nissandual mass flywheels. The vehicles listed at left have a

crankshaft tone ring built into theflywheel. The dual mass flywheelis not indexed on the crankshaftand can be installed differentways.When installed incorrectly, the

vehicle may not start, have acheck engine light and the enginewill not rev past 2,000 rpm. When removing a dual mass

flywheel from these vehicles, it’srecommended to make your ownindexing marks on the flywheeland crankshaft. When installingthe new flywheel, transfer yourmarks from the old flywheel tothe new flywheel to ease installa-tion and assure proper indexing. If you’ve already removed the

flywheel and did not make anyindexing marks, follow this pro-cedure for proper installation:1. With the flywheel removed,

look for the alignment dowel pin-hole on the end of the crankshaft. 2. Find the same alignment

dowel pinhole on the new fly-wheel. This can be done by find-ing the locating hole and notchon the front side of the flywheel(see Figure 5 on the previouspage).When you’ve located the notch

and hole on the front side, flipthe flywheel over and find thesame hole that goes all the waythrough the backside. Then lookat Figures 4-6 and find the dowelpinhole.

3. When both have been located, align the two holes andtorque the flywheel to the properspecifications.

4. See Figures 4-6 to aid in locat-ing the correct dowel pinholes. Courtesy of Schaeffler Automotive

Aftermarket, manufacturer of LuKClutches.

» TechTips

Reader Service: Go to www.uhsRAPIDRESPONSE.comUnderhoodService.com 49

Applies To:2006 300 3.5L2006-’07 300 5.7L2006-’07 Charger 3.5L2006-’08 Charger 5.7L2009 Grand Cherokee 3.7L2006 Magnum 5.7L

Customer Concern:P2767 trouble code (TorqueConv Clutch Press Ctrl SolenoidCtrl Circ Range/Perf) is setting.Transmission is in limp in mode.

Potential Causes: Lead Frame or TransmissionWiring

Tests/Procedures: 1. Check the wiring between the

transmission and the transmis-

sion control module. Make surethe #2 signal wire is not open,shorted to ground, or shorted toany other circuit.2. If the wiring checks OK, raise

all four wheels off the ground,start the vehicle and place theshifter in drive. While lab scopetesting the #2 signal wire, obtainsecond gear. When the transmis-sion is in second gear, thereshould be a 5-volt square wavepattern being produced by the #2sensor. If not, replace the sensor.

Tech Tips: The speed sensors are sold as acomplete assembly, which maybe called the “lead frame” or possibly the “electrohydrauliccontrol unit.”Courtesy of Identifix.

» TechTips Dodge \ Chrysler


Dodge Has a P2767 Code with Transmissionin Limp In Mode

Applies To:1998-2004 Intrepid 2.7L1999-2004 Concorde 2.7L 2001 LHS 3.5L2001-’04 Sebring 2.7L2002 300M 3.5L2002-’04 Intrepid 3.5L andStratus 2.7L

2003-’04 Concorde 3.5L2003 Stratus 2.4L

Customer Concern:Trouble codes P0172 and P0175;fuel pressure is OK.

Potential Causes:Camshaft Timing Oxygen (O2) Sensor

Exhaust Gas Recirculation (EGR) Valve

Tests/Procedures:1. Test to see if the EGR valve

is stuck open at idle. Make ablock-off plate and put it underthe EGR valve, if necessary.Replace the valve assembly ifit’s stuck open.2. Verify that the camshaft

timing is correct and repair asneeded.3. Check the downstream O2

sensor operation. It should switchlike the front sensor but at a slow-er rate. This will affect the waythe engine runs. Replace the sensor as needed.Courtesy of Identifix.

Chrysler’s Fuel Pressure Is OK, butCodes P0172 and P0175 are Detected

Since the introduction of theOBD II system, manufacturershave continued to improve onthe monitoring of evaporativeemissions — the complete evap-orative system is under a scruti-nized surveillance. Codes likeP0440 to P0456 are all related tothe fuel vapor control, includingleaks. Starting early this century,

manufacturers have increasedthe development of fuel vaporretention, preventing thevapors from escaping into theatmosphere. This promptedmany changes in the designand location of certain compo-nents such as charcoal canistersmounted near the fuel tank.A fuel tank pressure sensor is

used to monitor the pressuredecay in the system during thetesting and will turn on thecheck engine light if the pres-sure decay moves out of speci-fication. Remember that theevaporative system test will notbe performed if the fuel level isbelow a 1/4, as it would causefor too much pressure built upin the tank or simply wouldtake too much time to build anypressure. A helpful tool to identify leaks

is a smoke-generating machine.During the smoke machineprocess, loose or broken hosesare usually identified as themain cause of evaporative fail-ures. An additional componenthas started to surface and isbecoming the leading cause ofevaporative emissions leaks —

the fuel filler neck.Most fuel filler necks are made

of steel and are secured to thefuel tank via a rubber hose. Thefuel filler neck is usuallyenclosed in the rear fender wellwhere an accumulation of dirtand debris causes the filler neckto rust and leak. These modelsare hard to diagnose, as theinner fender protection must beremoved to get access. Othersare totally exposed behind thefender where plashing and roaddebris erosion removes paintand perforates the filler neck.The filler cap, which besides

not being properly securedafter refueling, may cause mul-tiple failures of the system aswell. The fuel filler cap mayhave a defective control valveand prevent pressure hold inthe system. Second, the fillerneck itself may have rust on theouter seam, which will preventthe cap from sealing properlyto the filler neck. Some modelshave the part where the capscrews on that is made of plas-tic and can be damaged by thefueling nozzle when insertedduring refill, which will pre-vent proper sealing. All of these scenarios will

cause the check engine light toturn on. So make sure to imple-ment fuel filler neck inspectioninto your regular vehicle main-tenance or during fuel tankremoval. This will preventcomebacks and headaches foryou and your customers.Courtesy of Spectra Premium. ■

» TechTips


Fuel Filler Necks and RelatedCheck Engine Light Conditions


»Shop


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quality, coverage and original match. Intermotor provides more extras like

factory-installed separator clips, anchors,protective loom and trays to keep

wires sorted properly and safely. Intermotor wire sets install with ease for

exceptional power, performance andextra-long service life. Visit

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Help your customers better understand TPMS with Bartec USA’s newTPMS Consumer Kit. “We surveyed hundreds of shops and found a com-mon message: technicians and counter people need help explaining whattire pressure monitoring systems are all about,” said Scot Holloway, CEO.This Consumer Kit comes with a counter mat, mouse pad, informativewall poster, large window banner, two versions of consumer-orientedbrochures and an attractive countertop display. Bartec also created acomprehensive reference book. Bartec’s goal in developing this kit is tobuild knowledge and confidence and improve on the abilities of technicians to help consumers better understand TPMS. Reader Service: Go to www.uhsRAPIDRESPONSE.com

ToughOne A/C compressors are performance-tested, premium productsthat meet or exceed OE specifications. Low defect rates — about halfthat of competing brands — mean fewer comebacks. ToughOne A/Ccompressors feature a low-friction coating used on the swash plate to improve the part’s durability, and PTFE-coated pistons improve perform-ance and reduce wear over time. The rubber-dampened clutch plate ensures smooth clutch engagement and reduces wear. ToughOne, avail-able exclusively from Advance Auto Parts Professional, offers industry-leading coverage for foreign and domestic applications. For the latestpromotions on ToughOne products, visit AdvanceCommercial.com/seasons or call your local Advance delivery store.Reader Service: Go to www.uhsRAPIDRESPONSE.com

Supercool offers the Power Jet Aerosol A/C Flush Kit,a ready-to-use, high-pressure flush system completewith 15 oz. replaceable flushing agent, nozzle depres-sor valve and hose. This easy-to-use flush kit appliesconstant pressure until the flush can is empty, withoutrequiring shop air. The Power Jet Aerosol A/C FlushKit features Supercool’s Flash Flush, a powerful andfast-evaporating flush that removes oil, debris andother contaminants from the A/C system. Flash Flushleaves no residue, is non-corrosive and is safe for allA/C systems.Reader Service: Go to www.uhsRAPIDRESPONSE.com

NAPA Silver Oil Filters are theright choice for conventional oilchange intervals. With 10%more cellulose filtering media,metal end caps to provide posi-tive seal to prevent oil bypass,an innovative combination by-pass and anti-drain back valve,and a coiled steel spring to prevent damage from pressuresurges, you can’t do better byan engine. Visit your localNAPA AUTO PARTS Storetoday for more information.NAPAFilters.com or 800-LET-NAPA.Reader Service: Go towww.uhsRAPIDRESPONSE.com

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

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In the automotive repair pro-fession, ASE certifications,manufacturer certifications

and years of service are justsome of the ways to distinguishone as a pro vs. a parts- swapping technician.

I try to approach each job as aprofessional. This includesdetailing my repair work andstriving to make each repair asneat and orderly as possible.

I recently got a car from asmall motor swap shop that Iused to visit once in a greatwhile. They never sent me a lotof work, but their techs wouldcall me constantly asking forinformation on how to repairsomething.

Grudgingly, I told them Iwould look at this one car,even though it didn’t soundlike one I wanted to deal with.

While checking under thehood, I found a lot of newparts slapped on and severalthings that were out of place,most of which were not fas-tened down correctly withtheir retainers or clips. Youcould tell they had no ideawhat was wrong or what theywere doing, and were onlythrowing parts at it, hoping itwould start.

The main complaint was thefuel pump wasn’t coming on.They had already replaced thefuel pump relay, and eventhough it had all the correct sig-nals (at the relay), it refused tocooperate. I found something

that I rarely see, but it doeshappen — the relay was assem-bled backward. For now, theeasiest solution was to reversethe leads at the relay. Once Iswitched it over, the car start-ed. It ran terrible, the servicelight was flashing and a misfirecode was stored.

Upon further diagnosis, Ifound even more issues; Ithought it was time to call theseguys and give them the news.

“We can handle it fromhere,” they told me. They paidfor my time, and, as expected,it wasn’t long before theyneeded more help. I could tellthere was already some tensionon the other end of the phone,and I was going to be thescapegoat for this car’s demise.

“I’d check the fuel pressuresince it sounds like that mightbe part of the original problem,before all this other stuff wentwrong,” I told him before herudely hung up the phone.

I always thought these guyswere a little shifty, and it wasn’tlong before I found out for sure.

The owner turned out to be justas unprofessional as his hiredhands. What was my clue? Hestopped payment on the check.I was furious. But, I cooleddown a bit. Let’s be profession-al about this, I told myself. Ikept my cool and called them.

“I’m not here to lie, cheat orsteal, and I’ve never-ever donethat to you or anyone else.Your lack of handling things ina professional manner portraysthe caliber of a person you real-ly are. If you had a problem, allyou had to do was call me orbring the car back. But, tryingto save a few bucks on yourpart, after the efforts I put inthis, is not acceptable. I don’twant your money. I also don’twant your techs calling me topick my brain for answers. It’snot about the money now; it’sabout the principle.”

I said my peace, and hung upthe phone. Case closed. Shopslike these give the rest of us abad name. I felt 100% betterafter handling it this way. Ididn’t see any reason to standthere toe-to-toe, and try to getcompensated for my profes-sional time. My professional-ism means more to me than afew bucks. Let’s face it, for arepair shop to insult anothershop, especially when theycouldn’t figure out the problemon their own, shows that theirtrue colors definitely came shining through. ■

By Scot t “ Gonzo” Weaver

» Gonzo’s Toolbox

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