Tomorrow's Technician

October 2012

� FULL THROTTLE DIAGNOSTICS � COMPACT UNDERCAR UPGRADES � SMOKIN' DIESEL PERFORMANCE

TomorrowsTechnician.com

UNDER THE HOOD 10Going Full Throttle: Mazda Driveability DiagnosticsWe take a look at the popular MAZDA6 and MAZDA3models and cover some of the common underhood repairsthat find their way into today’s repair shops. We’ll alsocheck out some of the new technology that has been incorporated into Mazda engines.

UNDERCOVER 18Subcompact Vehicle Undercar UpgradesLooking into the near future, it would appear that therewill be a shift toward smaller, lighter and more fuel-efficientvehicles. And, we believe that there will be some subcom-pact owners who will want to modify and improve these“grocery getters.” While the little Toyota Yaris and itscousins from Scion may be a little early for this market,we’re beginning to see that the availability of modificationparts will keep the popularity of the growing subcompactmarket around for a while. Find out what undercar opportunities there are for modifying these vehicles.

PERFORMANCE PRIMER 24Burnin’ Rubber and Blowin’ Smoke You may have not realized it, but diesels are making inroads into a number of racing venues. Diesel-poweredrace cars and trucks are setting land speed records atBonneville, winning endurance races at LeMans, and running more than 200 mph in the quarter mile at thestrips. Before you consider making a move into diesel performance service, check out what some of the expertsare saying about this growing niche market.

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CONTENTS

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Tech Tips: Volkswagen with DTC P1297 Stored in Memory 31

Report Card: Supercar Silhouette — Peugeot’s ONYX Concept 32

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Each month, Tomorrow’s Technician takes a look at some of the automotive-related student competitions taking place in this country, aswell as the world. Throughout the year in “Finish Line,” we will highlight not only the programs and information on how schools can enter,but we’ll also profile some of the top competitors in those programs.Because there are good students and instructors in these events, we feel it’s time to give these competitors the recognition they deserve.

Utah State Universityresearchers are walkingon air after setting aland speed record witha novel race car of

their own design. Adding to theirexcitement is the vehicle’s fuelsource: a USU-developed biodieselcrafted from surprising origins.“How many people get to drive a

car they helped build with fuel theycreated from a living microorgan-ism?” asks USU undergrad bio-chemist Michael R. Morgan, whodrove the dragster across Utah’sBonneville Salt Flats Speedway to itslandmark finish.The Aggie A-Salt Streamliner, as

it’s officially known, runs on yeastbiodiesel derived from the industrialwaste of cheese production. Thesleek, Aggie-blue hot rod was amongsome 200 high-tech racers compet-ing at the Utah Salt Flats RacingAssociation’s 2012 World of Speedevent Sept. 8-11. See the video at:

http://www.youtube.com/watch?v=mTDklVuEjmU“This is a real pole in the ground

for Utah State,” said LanceSeefeldt, professor in USU’sDepartment of Chemistry andBiochemistry and a principal facultymentor on the interdisciplinary proj-ect. “Setting the land speed recordin this vehicle’s class on sustainablebiofuel produced at USU under-scores the outstanding quality ofour school’s biochemistry and engineering programs and further

validates the technology in thisimportant sector.”At its top speed, the Aggie

vehicle clocked in at 65.344 milesper hour. At first glance, that speed

may fail to impress NASCAR fans oreven most interstate motorists. Butmake no mistake; it’s a head-turningachievement for a biofueled vehiclewith a one-liter, two-cylinder engine.The USU team raced the dragster inseparate runs, using petroleumdiesel and the yeast biofuel, respec-tively. Powered with the latter, thespeedster was able to match its pre-vious petroleum-fueled run.“Developing a biofuel on a large

enough scale to run in the dragsterwas a tough undertaking,” says USU

biochemist Alex McCurdy, a third-year doctoral student in Seefeldt’slab, who is supported by a NationalScience Foundation research assist-antship and is the recent recipient

edited by Tomorrow’s Technician staff


LIFE IN THE FAST LANE: USU-BUILT BIOFUELED DRAGSTER ZOOMS TO LAND SPEED RECORD

“How many people get to drive a car theyhelped build with fuel they created from a livingmicroorganism?”

–Michael R. Morgan

At Utah's Bonneville Salt Flats, USU biochemist Michael R. Morgan posesbeside the 'Aggie A-Salt Streamliner,’a USU-built dragster powered withUSU-developed biodiesel the undergrad drove to a land speedrecord.


of a departmental environmentalchemistry award. “It’s one thing toproduce a small amount in the laband discuss how it will work in the-ory. It’s another to actually put it ina dragster, while everyone watchesit take off.”With McCurdy, Morgan and

other student team members in thecolleges of Science and Agriculture,Seefeldt and Bruce Bugbee, pro-fessor in USU’s Department ofPlants, Soils, and Climate, havebeen working for more than a yearto perfect the production of thefuel using yeast and bacterial plat-forms, as well as developing fuelfrom carbon dioxide and the Sunusing microalgae platforms.“We’ve recently succeeded in

producing quantities of fuels fromall of these sources that have supe-rior properties in test engines, com-paring favorably to biodiesel pro-duced from soybeans,” saysSeefeldt, recipient of USU’s 2012 D.Wynne Thorne Career ResearchAward, the university’s top researchhonor. “The USU fuels are a renew-able, low-footprint replacement forpetroleum diesel and they don’tcompete for food crops.”Meanwhile, student and faculty

team members in USU’s College ofEngineering, mentored by ByardWood, professor and head of theDepartment of Mechanical andAerospace Engineering, have beentesting the USU biodiesels andreport excellent horsepower andfuel emissions. The dragster team,led by Michael D. Morgan, directorof USU Engineering’s StudentPrototype Laboratory (and,

incidentally, father of MichaelMorgan, the car’s undergraddriver), built the diesel streamlin-er, with assistance from UtahChassis and Mott Motorsports, inpreparation for the Septembercompetition.“It was amazing for me to

have my dad check my belt andgear and give me a ‘thumbsup,’” says the younger Morgan.“It’s just you and the car as youfeel it take off and rumble downthe track giving it everythingshe’s got. The Salt Flats lay outbefore you in an expanse so farthat you can see the curvature ofthe earth.”Morgan and McCurdy praise

the team effort that enabled USUto achieve the milestone.“It really is an honor to help

provide fuel for such a well-designed and engineered dragster,”McCurdy says. “We’re trying to getpeople excited about our biofuelresearch and I think setting a landspeed record ought to get theirattention.”Here is some additional video of

the dragster during some early testruns:http://youtu.be/FkhFWrYQPbA

MICHAEL MAKOWSKY NAMED 2012 MITCHELL 1 EDUCATOR OF THE YEARMichael Makowsky of Oakville, CT, was named the Mitchell 1 2012 Educator of

the Year during North American Council of Automotive Teachers (NACAT) conference held recently at Tyler Junior College in Tyler, TX. Each year, Mitchell 1recognizes one of the nation’s top teachers for excellence in automotive repairinstruction. Makowsky was presented with a check for $500 and a recognition certificate. He will also receive a one-year complimentary subscription to Mitchell 1’s ProDemand™ repair, diagnostic and maintenance information program for the school where he teaches.Makowsky has been an automotive instructor at the Porter and Chester Institute in

Watertown, CT, for six years, where he has been full-time for the past two years andwas part-time for four years. His automotive career also includes experience workingat various Chevrolet dealerships for 35 years. During that time, Makowsky received atremendous amount of training from General Motors, including being certified as aGM technician. He firstpassed all eight ASE auto-motive tests in 1976.Makowsky graduated withhonors from DenverAutomotive and DieselCollege in 1976. �

Do you have an outstanding student or a group of students that needs to be recognized for an automotive-related academic achievement? E-mail us at [email protected].

The Aggie A-Salt Streamliner,as it’s officially known, runs onyeast biodiesel derived from theindustrial waste of cheese production.Photo courtesy Eli Lucero/The HeraldJournal, Logan, UT


Mazda has long enjoyed a reputationas a performance car company withthe RX8 and MX5, as well as hasbeen able to consistently hit thetarget when it comes to affordable

sport sedans that are as reliable as they are fun todrive. In this article, we’ll take a look at the popularMAZDA6 and MAZDA3. We’ll cover some of thecommon underhood repairs that find their way intoshop. We’ll also check out some of the new technology that has been incorporated into Mazdaengines.

Common ComplaintsLet’s start with cars that have driveability

problems. One thing that hasn’t changed in allthe years I’ve been doing this are the basic complaints we hear. It’s either running rough atidle, missing or “skipping” under load, hesitating(at speed or throttle tip in) or there’s no power.It’s up to the service writer to ask the right ques-tions when the appointment is made so the techhas the information needed to make a successfuldiagnosis and repair.One of the most common failures we see on

both early- and late-model Mazdas is a torn airintake hose between the airflow sensor and thethrottle body. The symptoms that result fromthis failure are hard to miss. The usual complaint is a big stumble or stall on initial

on Mazda Driveabilit

Under the Hood

GoinG Full Thr

acceleration, but it may or maynot set a system lean code. As theengine torques on the mounts,the crack in the hose will open,allowing unmetered air into themanifold while, at the same time,reducing airflow through the sen-sor. Of course, when the enginestumbles, the crack closes, allow-ing the engine to accelerate,starting the entire process all over.Many times, the customer will mistakenly think the transmissionis the problem.

Although it’s simple to diagnose

with a visual inspection, I’ve seensome good technicians tricked bythis one. Be sure to inspect the hoseclosely for cracks that won’t be obvi-ous but will become evident whenthe engine is loaded against themounts.A vacuum hose can be the cause

of another problem that may haveyou shaking your head.On the popularMAZDA3, youmay have a cus-tomer complain-ing about asiren-like orscreechingnoise comingfrom underthe hood.The moreattentiveones maymentionthat itchanges withthrottle position. While your first thoughts will

have you looking at the drive belts,the real culprit is a failed PCV hoselocated under the intake manifold.The hose will weaken and split,allowing air to be drawn through thehose and causing the noise. While

the hose can be accessed withstarter removal, some techs feelremoving the intake manifold is aneasier way to go. So, while the repairsounds simple, be careful when writing the estimate.While we’re talking about the

MAZDA3, there have been somereports of an erratic stalling problem that may or may not set acrank sensor code, but the sensorwill check out fine. If the car hasaftermarket drive belts installed withan alternate cut, suspect a buildupof static electricity that finds its way

to the sensor. You may see sparksjumping to the sensor when the caris idling, but if you’re faced with an intermittent stall, keep it in mind.

No Zoom-ZoomWhen it comes to no-power

complaints, a couple of thingsshould come to mind. As with anydiagnosis, your first step should be

to hook up your scanner and seewhat codes are stored. If a

code is present, besure to look atfreeze-framedata to seewhat the con-ditions werewhen thecode wasset. Manytimes,you’ll havea systemlean codeas the only

hint for the no-power issue, and

this coincides with the things we’rethinking about for a low-powerissue.Leave the scanner hooked up for

the initial road test so you can lookinto the system as the car is driven.

Look at the temperature parame-ters to confirm that the coolant andair intake readings are correct andchanging as expected.On the road, look at the fuel trims

and calculated load as your windowinto what the fuel system is beingtold to do and how well it’s reachingthe goal. If all looks good on theintake side, the next step will haveyou checking exhaust back pressure.I’m sure we all know what the trim

numbers mean at this point; it’s aneasy concept to grasp. If there is aminus sign in front of the number,

TomorrowsTechnician.com 11

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the ECU is removing fuel; no minussign means fuel is being added. Inan ideal situation, the numbers areclose to zero, since the only way theECU knows what the engine needsto meet its fuel requirements will bethe pre-cat air/fuel ratio sensor (for-merly known as the O2 sensor), withsome consideration given to rearO2 sensors. If you’re faced with a car with

a low-power complaint or arough idle, take a look at thelong-term trim. If you have a positive number in the 20s, thinkabout the things that will make itrun lean. If you also have a mis-fire code or a rough idle, don’toverlook the possibility of anintake gasket leak. While it’s nota real common problem, we haveseen some on the four-cylindercars. If you’re looking at a multi-bank engine, make note if bothbanks are showing a similar num-ber or if it’s just one bank.Freeze-frame data will also tellyou when the limit was reached. You can make some decisions

once armed with this information. Ifthe limit was reached at idle, itwould have you looking forunmetered air finding its way intothe engine. It could be the EGRvalve, but it could also be an intakemanifold gasket leak or the O-ringseals on the V6s.On the four cylinders, a leaking

intake gasket will usually set a mis-fire code, along with the systemlean code. Usually all it takes is ashot of intake cleaner at the mani-fold flange and a stethoscope toconfirm the diagnosis. The six-cylinder engine’s upper manifoldO-ring leaks can be a bit morechallenging and, if in doubt, asmoke test will confirm you’re onthe right track.

We already talked about thePCV hoses failing, and this willundoubtedly cause a lean condi-tion with or without the noise.Other not-so-obvious sources ofvacuum leaks include a leaking

EGR valve that’s more commonon the older cars (but there arestill plenty of them out there),and sticking purge valves on thelater cars.The EGR valve is an easy diag-

nosis; if exhaust gases are leakingthrough the valve, it will benoticeably warmer than the adja-cent area. The purge valve can bea bit more difficult since theproblem is more a sticky valvethan it is a hard failure. This isone of the times where you haveto rely on what you know andmake your best decision. If youhave an evap code, along with asystem lean with no obviousproblem for either, it’s a safe betthat the purge valve is sticking.Any sign of charcoal contamina-tion should have you recommend-ing a new canister.On the other hand, if the

freeze-frame information is tellingyou that the code was set atspeed, the idle is smooth and thedriver reports no additionalsymptoms, think about whatmakes it lean under those condi-tions. My first thought would bethe mass air sensor; by now, weshould all be aware of how debrisfinds its way to the hot-wire sen-sor. If you’re going on an initialroad test after checking andclearing codes and memory, setthe scanner up to monitor thefuel trims and calculated load.Before you hit the road, makesure the short-term trim is react-ing as expected.On the road, do a couple of

wide-open accelerations makingnote of the calculated load — itshould be a 90-plus percentage. Ifnot, take a close look at the air sen-sor for contamination. The sensors can be carefully

cleaned, and we’re having goodluck with some of the productsdesigned for the job; but be gen-tle as they are fragile. We look atcleaning the sensor as part of thediagnostic process and recom-

2009 mazda V6:

The MAZDA6 was available witha 60° 3.7L V6 engine. DesignatedMZI, and developed for the 2008North American Truck of the Year-winning CX-9 model, the enginewas then fitted to the 2009MAZDA6.The list of advanced features

includes light and stiff aluminum con-struction for the block and cylinderheads, a forged-steel crankshaft withinduction-hardened journals and vari-able intake-valve timing. Dual over-head camshafts are chain-driven andequipped with maintenance-freedirect-acting bucket tappets.Cast-in iron cylinder liners pro-

vide a dependable bore surface.The intake manifold is injection-molded nylon-reinforced plastic tosave weight. Two close-coupled cat-alytic converters minimize the timerequired following a cold start forthe emission controls to reach fulleffectiveness. A dual exhaust sys-tem provides low restriction forexcellent high-rpm power.

To achieve best-in-class smooth-ness and quietness, the MAZDA6s’3.7L V6’s crankshaft has a full com-plement of counter-weights and adual-mass damper. The aluminumcylinder-head covers are rubber iso-lated to minimize the amount ofradiated valvetrain noise.


mend a new sensor to ensure asuccessful repair (note that on theinvoice to prevent any misunder-standings).Once the problem is diagnosed

and repaired, make sure that thebolts holding the sensor to the air fil-ter housing are tight, that the air fil-ter box is not allowing unfiltered airinto the sensor, and that the air filterelement is of high quality and ingood condition. There have alsobeen reports of the sensor housingbolts coming loose, letting dirt intothe air stream. Be sure all the air isbeing filtered.

Managing MisfiresAs I mentioned earlier, misfires

that are evident shouldn’t be a realchallenge to diagnose. To protectthe cat converter, misfires are moni-tored closely and it’s rare not tohave the check engine lamp evenblinking along with a solid misfire.Your first step should be to get thecodes and other info the system iswilling to share.You would expect a misfire code

directing you to the offendingcylinder, but don’t overlook theother available information. Anaccompanying fuel-trim code, forexample, is an important clue as towhat could be causing the misfireand, if nothing else, it should haveyou looking for additional issues asthe misfire is diagnosed. Don’t for-get to check the freeze-frame infor-mation for conditions when thecode was set. This is especially trueif the car is currently running welland the misfire is intermittent. Before the initial road test, look

at the live data to see if the tempsare accurate, whether the throttleswitch is changing, if the air masssensor is reacting as expected (andlook at the long-term trim to see ifthe computer is adding or removingfuel to maintain the correct mix-ture), and see if short-term trim isclose to zero. You should keepthese things in mind as the diagno-

sis moves forward. In recent years, Mazda has

changed over to the coil-on-plug system to bettercontrol those catalyticconverter-killing misfires.While I’m sure this systemdoes a great job of dealingwith misfires better than theold ignition wires, it is notwithout its problems. In manycases, the easiest way to confirma coil problem is to switch itwith an adjacent cylinder andconfirm the misfire moves withthe coil. Don’t forget to look atthe condition of the spark plugsand it takes only a couple ofminutes to test compression.With extended service intervals,

drivers tend to forget about routinemaintenance. With that said, if theplugs are shot, chances are the car isin need of a service. Fix the misfirefirst, but don’t overlook the opportu-nity to recommend the rest of theservice.

Our diagnostic and repair strate-gy changes a bit when you’re deal-ing with a six cylinder where it’smore labor intensive to access thecoils. In the case of a solid misfire,before you dig into removing themanifold, listen to the injectorswith a stethoscope to confirm theyare working and sound similar. Alsodouble-check for any severe vacu-um leaks. Of course, either ofthese problems would result in ahigh positive fuel trim number. Ifwe suspect a coil failure, we alwaysrecommend that all coils in thatbank be replaced along with thespark plugs.I know we’re all familiar with

diagnosing and repairing misfiresand it’s just our nature to get intothe job and fix it with an “I know

how todo this”attitude. But,in this day and age,it’s more important thanever that you get into the serviceinformation and online forums to

check for service bulletins andrecalls. You can spend a lot of timelooking for that random miss at1,500 to 2,000 rpm, only to findout that there was a reflashoffered that took care of it. Makeit one of the first steps, even ifthere are no bulletins, as I’m sureyou’ll get some useful tips on therepair.

Pedal to the MetalThe latest technology from

Mazda that’s finding its way to us isdrive-by-wire throttle control.These systems are pretty muchtrouble free but have to be takeninto consideration as we performroutine service and diagnose prob-lems. It’s really a fairly simple sys-tem; a 12-volt motor opens the

“I know how to do this” attitude.

throttle as controlled by the PCMbased on various inputs.Along with the electronically

controlled throttle body, an accel-erator pedal assembly was addedthat mimics the feel of a mechani-cal throttle, yet houses the neces-sary accelerator pedal position sen-sors that tell the PCM what thedriver is asking for. It’s easy to thinkthat we replaced a simple cable-operated throttle with a complexelectronic unit, but this has reallysimplified things, while providingengineers with even more optionsfor vehicle performance, conven-ience and vehicle stability. It changes the way we service

these cars when it comes to clean-ing the throttle plates. To preventdamage to the electronics, it’simportant that we use very littlesolvent in the process. The beststrategy is to apply the solvent tothe shop rag or brush that’s beingused in the cleaning process, withvery little or no solvent beingsprayed into the housing. If youhave to use some solvent in thehousing, avoid the shaft area whereit could find its way into throttleactuator and position sensors.One of the advantages of this

system is its ability to open thethrottle and maintain the target idlespeed, even if the plate is dirty,eliminating the need for and thelimitations of an idle speed controlmotor. That certainly doesn’t meanthe plates should be ignored; it’sstill important that they are cleanedto ensure smooth operation. These systems have been very

reliable. While there were someproblems when the system was firstintroduced in 2003, most of thosetroublesome units were replacedunder warranty, although we haverecently seen one. The service bul-letin is available in your serviceinformation, but the short descrip-tion is if there is AA, AB or BA iden-tifying designations on the throttlebody, suspect a bad unit and

replace it with a unit carrying a BB. When it comes to diagnosing this

system, a scanner with OEM capa-bilities will be a big help. As youwould expect, there are codesrelated to every part of the systemthat has limp modes connected toensure the safety of the vehicle.RPM may be limited to a predeter-mined point or the throttle bodymay be held to an idle speed untilthe codes are cleared.Don’t be intimidated by all those

wires on the throttle body. You havetwo wires that control the throttlemotor, with the others dedicated toletting the PCM know what’s goingon with redundant throttle positionswitches that are part of the throttlebody assembly.When looking at the position

switches on the throttle body, beaware they work in opposite bias,using a 5-volt reference or input;switch one will read high voltageat idle (approx. 4.3V), while switchtwo will be low voltage (0.8V).Look for the opposite voltages asthe plate moves toward wide-open throttle. The PCM will make its decisions

by looking at what the throttle isdoing, along with the acceleratorpedal position switches located inthe pedal assembly; again these areredundant switches for reliability.These switches are different in con-struction being a non-contact Halleffect-type sensor rather than themechanical sweep-type switch. Theyare tested in the same way by look-ing for smooth voltage outputthroughout the range of movementwith no dropouts or spikes. Both pedal switches read low

voltage at idle and increase as thepedal is depressed. Be sure tocheck the specs as its normal forswitch one to read half a volt morethan switch two. There have beenno reports of problems with thepedal assembly with most of thefailures leading to throttle bodyreplacement. �


Back in the late 1970s, I went to work fora VW/Audi repair shop in Bellevue, WA.Within a year, I had pretty muchreplaced my entire fleet of personalcars with VW products of various types.

One of the first cars I purchased was an earlyRabbit with the carbureted, 1.5L engine. I got itcheap because the car didn’t run well, but afterupdating and sorting out the carb, the car was somuch fun to drive that I started buying, fixing andselling them on a regular basis. My favorites werestill the air-cooled cars, but for daily commuting, inany weather, the water-cooled cars were morecomfortable.What made that early A1 Rabbit, and its

competitors like the Civic, Tercel (1980), GLC andSubaru DL, so much fun to drive was the light-weight (right at a ton) FWD and a free-revvingsmall engine that made power-to-weight ratios aperformance standard. Compared to the cars provided by American manufacturers, these carsfelt like you “put them on,” instead of just sitting inthem.Like those early VWs, today’s Toyota Yaris (see

Photo 1) and its sister vehicles, the Scion xA, xB

and xD are tiny, lightweight vehicles. And, withmore than 100 horsepower, they, too, can be fun todrive. Performance, though might be stretchingthings a bit — or is it? The models I listed abovewere all entry-level cars that didn’t really inspireperformance driving, but after a little research Ifound that all were used in some form of at leastamateur racing with some success. The Yaris is usedfor racing in several types of motor sports (seePhoto 2), but mostly in other parts of the world.When I checked in with my friend, Charles

Adapted from Larry Bailly’s article in

Photo 1

undercover

Toyota’s Yaris and its cousins — the Scion xA, xBand xD, offer the Sub-Compact Market Segmentundercar performance modification opportunities.

A Reduction in ‘Class Size’Subcompact Vehicles Offering Undercar Upgrade Opportunities

Damewood at Z Sport (www.zsport.com), he said hedidn’t know of any modified cars in our Seattle area.After searching through websites and online forums,

it is obvious that there is a following for these cars, justnot so much in the U.S. Small cars sell much better injust about every other country. That could all change asmore and more sub-compact models are exported tothe U.S. from Europe and Asia. Asian models that areavailable here are the Honda Fit, Chevy Aveo (Daewoobuilt), Nissan Versa, Ford Fiesta and the Hyundai/KiaRio/Accent. Most of these cars come with both largerand smaller engines in other countries, and most areavailable with diesel power in other countries. I feel thatdiesel may catch on again in the U.S., once we see theprice of fuel rise and fuel economy becomes a largerissue. Turbocharged gas and diesel versions of the Yarishave been available in other markets, as well.

From the Front …One of the things I especially liked about my first

Rabbit was its simplicity. Strut-type suspension had beenaround for a while by then, but the strut suspension onthe Rabbit was about as plain as it can get. TheYaris is just as, if not more, simple than that car.The front strut (see Photo 3) isnothing more than a coil-overshock, as the steering arm andlower control arms are connected at the separatebearing carrier. Removal isa simple process ofseparating the strutfrom the bearinghousing, disconnect-ing the link arm from thestrut housing (see Photo 4) and

removing the upper mount from the body.Everything else is standard practice as far as com-

pressing the spring in a strut fixture and removing theshaft nut from the bearing plate. Since these cars are solight, replacement of the upper mount will not usuallybe necessary. Although, if an inspection reveals anycracking of the rubber however, replace it. Make surethe plate moves freely after reassembling the strutassembly and reinstall in reverse order. Note: Whenordering parts, the struts are different side to side, soyou will need to order a set, or individual struts for eachside. The difference is the shape of the spring plate andmount for the sway bar link.There is very limited factory adjustment provided for

alignment, other than toe adjustment at the tie rods.Aftermarket camber bolts are available to allow foradditional camber adjustment, but except for perform-ance tweaking, if the alignment cannot be brought intospec, look for signs of body damage, subframe mount

Photo 2


Photo 3


problems or other factors that wouldcause the alignment to change.The front wheel bearings are

standard, press-in duplex roller bearings.Be aware that the bearing is different,depending on whether the car has ABSor not. The ABS sensor should always beremoved before any work is done on thehub or bearing to prevent damage tothe sensor. The bearing assembly can bereplaced with an on-car bearing press orthe bearing carrier can be removed andthe bearing replaced with a shop press.Removal of the bearing housing, howev-er, will require rechecking the alignment,unless you are very thorough aboutmarking the housing and strut relationship before disassembly.The front sway bar is mounted behind the steering rack, (see Photo 5) between the front sub-

frame and the body, so even replacing the bushings is labor intensive. The sway bar links areequipped with tie rod ends on both ends, so unless they are bent or the boots are damaged,they will probably last for the life of the car.In researching this article, I did find an interesting TSB from Toyota dealing with the

relationship between tires and alignment problems. If you come across any car with a lead, pullor control problem that isn’t readily apparent, this might be a good article to look up and addto your knowledge base. The TSB is #TSB-0391-08 and is titled Repair Manual Supplement,Vehicle pulling to One Side, dated December 24, 2008.

… To the RearThe rear suspension is even more basic than the front

(see Photo 6). The rear springs and shocks are separateunits, supporting a beam-type axle that acts as thetrailing arms. Some models included a sway bar thatdoesn’t exist on the base model. The rear shocks

Photo 4

Photo 5


are just double-acting dampers andare identical side to side. The shocksare also the limiter for the movementof the rear axle, so care should betaken to support the axle when theshocks are removed.The springs can be removed by

disconnecting the shocks and carefullylowering the axle. Make sure to getthe insulators reinstalled properlywhen the springs are reinstalled.Rear-wheel bearings are the

modular, hub/bearing-type bolted tothe trailing arms as a unit. Like thefront wheel bearings, these units aredifferent for cars with or without ABS.As noted earlier, any repairs on thebearing or hub should begin with disconnecting or removing the ABSsensor to prevent damage.

Taking a BrakeNothing out of the ordinary here,

either. Front disc brakes (see Photo7) with vented rotors and rear drumbrakes are fully adequate for thesecars. ABS, stability control and whatToyota refers to as Electronic Brake-force Distribution (EBD, a load-sensing brake proportioning system)are on some models. Before order-ing any parts for these cars, you willneed to know which system theyuse. The rear brakes are self-adjust-ing either when the car is braking inreverse, or when the parking brake isused. Whenever the rear drums areremoved, the adjusters should bechecked for free movement. Even at100K miles, this Yaris still has accept-able lining remaining (see Photo 8).

Online PerformanceFrom the amount of parts available

from a number of suppliers, thesecars can be modified to just aboutany level from mild to wild.Spring upgrades are available

from popular manufacturers such asKsport (www.ksport.com), Tein(www.tein.com) and Eibach(www.eibach.com), as well as manyothers. Strut upgrades are avail-able, including completely

adjustable coil-over units for settingup the car for improved handlingand lowering the car. Tire Rack(www.tirerack.com) is a good placeto check for suspension kits, alongwith tire and wheel packages. Sway bars are available in many

different diameters, for both thefront and rear to tighten up thesuspension and reduce body rollcaused by the relatively soft stocksuspension.There also are big brake kits avail-

able from several vendors, but theprevailing opinion among driverswho use these cars for autocross is —big brakes are probably not requiredfor this type of use, simply becausethe car is so light. I have to agree(having autocrossed my A1 Rabbits)that braking is not a big problemwith light, well-handling cars.A supercharger kit from Blitz

(www.blitzpowerusa.com) shouldprovide enough added spunk tomake a standard Yaris into a littlescreamer.

Final NotesThroughout the 1970s, a

fundamental change took place inthe U.S. as we encountered fuelshortages, insurance increasesbased on horsepower and the totallack of cars that were available fromthe American car companies, putting the import vehicle/repairmarket on the map.Over the next decade, it would

appear that a lot of the same dynamics are going to force a shiftback to smaller, lighter and morefuel-efficient vehicles. That’s OK forsome people, but there are still thosewho will want to modify and improvetheir grocery getters. The littleToyota Yaris and its cousins fromScion may be a little early for themarket, but with the latest modelsand the availability of modificationparts, they will be around for a while. I think I might just go out and

get one for myself, and playaround a little. �

Photo 6

Photo 7

Photo 8


Performance Primer

OPPORTUNITIES GROW FOR DIESEL PERFORMANCE SPECIALISTS

Burnin’ Rubber andBlowin’ Smoke


For engine specialists whoonly service gasolineengines, diesels can seemrather foreign and unat-tractive. Diesel engines

don’t have carburetors, they don’thave spark plugs or ignition sys-tems, and most of them don’t revanywhere near as high as a gaso-line-powered performance engine.

Most people associate dieselengines with truck and tractorpulling events, not traditionalmotorsports. There are no diesel-powered NASCAR races or Indycars. But, diesels are makinginroads in other types of racing.Diesel-powered race cars andtrucks are setting land speedrecords at Bonneville, winningendurance races at LeMans, andrunning over 200 mph in the

quarter mile! As one racer told us, “The first

time we showed up at our localdragstrip with a diesel-poweredtruck, nobody took us seriously.But after the smoke cleared andeverybody saw how fast the truckran, they realized diesel drag rac-ing is no joke. The fan base fordiesel-powered drag racing hasbeen growing ever since.”

So you may want to consideropportunities in diesel serviceand performance on yourroad to technician success.But, before you do, checkout what experts in the fieldhave said about this market:

Dan Scheid of Scheid Diesel(www.scheiddiesel.com) in TerreHaute, IN, says his shop has beeninvolved with diesel performancework since the 1970s. “We startedout doing modified fuel systemsfor tractor pullers, then expandedinto engine work. As our cus-tomer base grew, we added moreequipment, including a CNCmachine to custom fabricateparts, and a 4,000 hp dyno fordialing in diesel engines.”

Scheid has been racing a twinturbo 5.9L Cummins diesel pow-ered dragster, which was the firstdiesel dragster to crack the 200mph barrier. “We’re also buildingdiesel drag racing engines fortrucks. One of our customers has a


diesel drag truck that is running inthe low 9’s at 155 mph.”

Scheid says serious racers arespending a lot of money on theirdiesel performance engines, up to$60,000 or $70,000 dollars. Whowouldn’t want that kind of work?

“Any engine builder who is currently doing gasoline engine performance work could probably dodiesel performance work too,” saysScheid. “You do have to learn aboutdiesel fuel systems and how to cor-rectly set up the injection pump,injectors and turbo. But the machinework you do on the block, heads andother internal parts are pretty muchthe same as any other performanceengine.”

Scheid says that many diesel per-formance engines are running 130 to180 psi of boost pressure. When youmodify a stock engine to producesignificantly more power, you alsohave to increase the flow capacity ofthe fuel system. Scheid says he hasmodified a 12-cylinder mechanicalinjection pump so that the output fortwo cylinders can be routed to a single cylinder to double the fueldelivery. He also modifies the injec-tors by increasing the number andsize of the nozzle orifices. Strongerfuel lines are also a must to handlehigher fuel pressures.

Scheid says the engines he buildsare designed to run on diesel only.

The rules for most pulling events donot allow power adders such aspropane, alcohol or nitrous oxide,but on the dragstrip, power addersmay be legal. Most diesel enginesare allowed to run water injectionand/or an intercooler.

TAKING IT TO THE STREETS There are also ample opportunities

to do diesel performance modifica-tions for the street. It’s fairly easy totweak the turbo and squeeze anextra 100 or more horsepower out ofan engine without sacrificing fueleconomy or everyday driveability. Tomaintain good driveability and throt-tle response, you want the turbo tospool up quickly and provide goodlow end torque.

Most street-driven diesel trucks aregoing to develop peak powerbetween 1,800 and 3,200 rpm.Depending on how the truck isgeared, a drag truck may be set upto run at a somewhat higher rpm. Butit doesn’t take a lot of revs to make alot of torque with a diesel.

Lenny Reed of Dynomite Diesel Performance, Monroe, WA, (www.dynomitediesel.com) saiddiesel engines in street trucks runbest with a camshaft that develops alot of cylinder pressure and a broadtorque band. Reed drag races aCummins-powered truck that devel-ops 950 hp and runs in the mid-10s.

A high lift, long duration cam thattypically produces a lot of high rpmpower in a naturally aspirated gaso-line engine would be the wronggrind for a diesel.

A diesel is a compression ignitionengine, so valve overlap must be limited to keep pressures high in thecylinders at low rpm. Also, piston-to-valve clearances are limited, sothere’s not much room for increasingvalve lift. Because of this, thecamshaft has to work with the turboto create power and torque wherethe engine can use it. The key torealizing performance gains in adiesel engine is tuning the injectorfor the best timing, and correctly sizing the turbo.

Craig Johnson of Big PowerDiesel (www.bigpowerdiesel.com) inLancaster, CA, is another dieselengine builder who specialized inCummins engines. He builds modi-fied engines for both pulling anddrag racing (though pulling is not aspopular on the West Coast as it is inthe Midwest).

“One of our customers has aDodge truck built for sled pullingthat produces about 1,000 hp witha single turbo and mechanical fuelinjection system. The engine launchesat about 5,000 rpm, and is connectedto a single forward gear drop box.”

Johnson says anybody who is seri-ous about pulling eventually builds atruck that is a dedicated puller ratherthan a dual-purpose street driventruck. The kind of engine and drive-train modifications that are neededto make a puller competitive are notthe type of modifications you wouldwant on the street.

“Somebody who might spend$1,000 to $1,500 for some typicalstreet performance modifications canstill get good fuel economy and dri-veability. But, if you want to be com-petitive on a dragstrip or at a pullingevent, you need an engine and avehicle that is purpose-built. Some ofthese guys will spend $45,000 to$55,000 or more on their enginesalone.”

There are plenty of opportunities to do diesel performance modificationsfor the street. It’s fairly easy to tweak the turbo and squeeze an extra 100or more horsepower out of an engine without sacrificing fuel economy oreveryday driveability. To maintain good driveability and throttle response,you want the turbo to spool up quickly and provide good low end torque.

FROM HOBBY TO HABITOne of the many Midwestern

diesel engine builders is Van Hasleyof Hasley Machine (http://haisleymachine.com) inFairmont, IN. Hasley has been doingdiesels since 1985. He initially gotinvolved in performance diesel workas a hobby, but it quickly grew into afulltime business. He now specializesin B-Series Cummins engines forboth drag racing and pulling.

“One of the limitations of thestock Cummins block is that it cansplit in two when you push it too far.So we had LSM in Waterford, MI,make us some billet steel blocks, andthat solved our problem.”

Hasley says his little shop in thecornfields of rural Indiana has earneda national reputation for buildinghighly competitive engines. One ofour customers won the NationalTractor Pullers Association (NTPA)points competition. We also won theprostock division of the Central OhioTruck & Tractor Pullers title.

Hasley blueprints and assemblesthe engines he builds in-house, butuses a machine shop in Muncie, IN,to perform the actual enginemachine work. He uses ZZ CustomFabrication in Wichita Falls, TX, dorework his cylinder heads and buildcustom intake manifolds. When he’sdone, a 360-cid Cummins dieselengine may produce as much as

2,200 hp depending on how the turbos are set up. Engines may haveone to three turbos, depending onthe application.

The money that people are put-ting into these engines can really addup. Hasley says some of his cus-tomers are spending $30,000 to asmuch as $80,000 for a professionallycompetitive engine. In addition, theymay spend $13,000 to $15,000 onthe fuel system, and another $15,000to $20,000 for turbochargers.

In spite of the money that is beingput into some of these engines,diesel racing is not a high dollarsport as far as prize money paid tothe racers is concerned. Hasley saysthe prize money for a win even at anational event seldom exceeds$1,000. The people who are spend-ing this kind of money on diesel racing are doing it because theyenjoy the sport, not for sponsorshipmoney or big purses.

INTERESTED IN MOREDIESEL ARTICLES?

Visit underhoodservice.com andsearch Bob McDonald.

McDonald, who owns AtlanticEngines (http://atlanticengines.com)in Granite Falls, NC, specializes indiesel performance and has writtenarticles on light-duty diesel engines,as well as a book on the Ford PowerStroke. �

You can build an 800-hp big block Chevy for the street or strip thatprobably won’t last over 20,000 miles before you have to tear it down,and you don’t get very good fuel economy. For the same money, youcan build an 800-hp turbo diesel engine that will last 150,000 miles anddeliver great fuel economy.


Tomorrow’s Technician October Crossword

©Solution at www.tomorrowstechnician.com

ACROSS1. Tire casing5. Dash gauge faces8. Electronic fault-finding system, briefly (1,1,1,1,1)9. Big-rig noisemaker (3,4)10. Online automobilia-auctions site11. Shop's labor-charge system, perhaps (4,4)13. Item left on pump, perhaps (3,3)14. Parts supply-chain middleman17. Diagnostic device for 8-Across system (4,4)19. Removed air from brake system22. Underhood power producers23. Dieseling or auto-ignition (3,2)24. Detailed design description, briefly25. Essential body-shop tools

DOWN1. Pre-EFI starting aid2. Twist-off cooling-system parts (3,4)3. Battery's corrosive content4. Unexpected engine stoppages5. Length of time engine valve open6. Word on Hawaii plates7. Planetary gearset's central element (3,4)12. Fuel containers (3,5)13. Seals between engine parts15. Add weight to wheel16. Uplifting service-bay equipment18. Dwell ____, ignition-timing spec20. Parking-lot souvenirs, sometimes21. Engine-block material, often

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MODEL(S) AFFECTED: ALL1998–2006 1.8L TURBOVEHICLES.

CONDITION: DTCs P1297 (17705) or P1557

(17965) are stored in DTC memory.This may be caused by intake hosesleaking (during boost conditions),due to incorrect torque on clamps orimproper placement, or worn or tornintake hoses, etc.

SERVICE PROCEDURES: Perform an intake system pressure

test to detect leaks in the intake system as follows: 1. Separate the intake hose from

the mass air flow sensor (MAF)assembly. 2. Remove the crankcase ventila-

tion hose from the PCV valve andclose off the crankcase side of thevalve with the plug (orange arrow,Figure 1), hose and clamps (suppliedwith the turbocharger tester, P/NVAG 1687).

TIP: This will disconnect theengine crankcase from the intake system.3. Insert the air pressure adaptor,

P/N VAG 1687/1 (blue arrow, Figure1) into the intake hose between the

MAF sensor and the intake system(clamp using the existing hoseclamp).

TIP: The hose at the throttleassembly will stay connected duringthe test.

PRESSURE TEST:1. Attach the outlet hose of the

turbocharger tester to the fitting onthe air pressure adaptor (blue arrow,Figure 2).

2. Close the outlet valve after thegauge. 3. Back off the pressure regulator

knob of the turbocharger tester fullyto protect the gauge when shop airsupply pressure is applied to theassembly. 4. Attach an air line to the inlet

fitting on the turbocharger tester. 5. Open the valve between the

regulator valve and gauge. 6. Adjust the test pressure up to

0.5 bar by turning the regulatorvalve.

Note: Do not pressurize the system above the 0.5 bar! Doing sowill force oil into the intake throughthe throttle body assembly, causingdamage to the engine.7. Slowly open the outlet valve

(after the gauge) to test the hoseconnections. 8. Observe the pressure gauge for

a drop in pressure. TIP: Some pressure will be lost

past the throttle plate.9. Apply soapy water or leak-

check liquid to all intake system connections to check for leaks.

TIP: An ultrasonic tester may alsobe used to locate leaks.10. Repair any leaks that are

found. 11. Remove the plug from the

crankcase ventilation hose. 12. Remove the air pressure

adaptor and reinstall the hoses. �Courtesy of Mitchell 1.

Tech Tips

figure 1

Volkswagen DTC P1297 or P1557 Stored in DTC Memory

figure 2

This month’s Tech Tipsare sponsored by:

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that are located onthe roof, the V8transmits its 600bhp (brake horse-power) to the rearwheels via a six-speed sequentialgearbox. Fitted with tires speciallydeveloped by Michelin, (275/30 atthe front and 345/30 at the rear),

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the Onyx offers its adorers a visionof tomorrow. �

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