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Friday, March 23, 2012

Northwest Herald Dr. Gizmo Column March 16, 2012



"Dr. Gizmo"
By Phil Arendt

Brake System Fault In Newly Purchased Used Vehicle
Question 1
Recently, I purchased a 1997 GMC C1500 Sierra pickup with a 5.0-liter engine.  Right after the purchase I noticed a pulsing in the brakes.  Also, for a second when I apply the brakes they pull left and then straighten out.  I checked the front pads.  They look new.  Also, there are new hoses on the calipers. 

I took the truck to a repair shop where a technician verified that someone had just replaced the brakes.  He also did a wheel alignment and checked the tire pressure.  Despite his work the brakes still pulse and pull.

What do you think should be done next?  H.L., e-mail

Answer 1
It’s possible for someone to replace the brake pads and not machine or replace the rotors.  It’s also is possible air is trapped in the system.  Bleeding brake fluid and air should be considered.  In addition it is possible a valve in the antilock brake system module may be sticking causing the pulling.  If bleeding air from the module and lines does not cure the trouble it may be necessary to replace the module which might cost a bundle.  Also, the rotors may need machining or replacement. 

Worn Engine Mount Causes Engine Stalls
Question 2
I own a 2006 Chrysler Pacifica.  Sometimes when I put the transmission in reverse the engine stalls.  When it stalls I hear a clunk sound just before it stalls.  It doesn’t happen often but usually it happens in the morning upon the initial start of the day or after the vehicle is parked for several hours.  I found that if I wait for the engine speed to drop before I place the transmission in reverse it does not stall.  When it stalls it restarts without any problem.

I called my repair shop about the trouble.  The manager assigned my call to a technician who asked a lot of questions but could not come up with an answer.  I took the car to him but after some testing he could not find anything wrong.  Also, it did not stall for him. 

I’m concerned the engine will stall and not restart and I will be stranded.  Do you have any suggestions? L.T., e-mail

Answer 2
This indeed is strange but don’t fret there might be an explanation for the condition.  After checking industry web sites a situation surfaced similar to yours.  As it turned out in another Pacifica the cause of the trouble was a broken engine mount.  When the engine was started, and transmission was placed in reverse, there was excessive movement that caused the engine to push against a wire harness.  The movement pinched the wires and caused the engine to shut off.

Ask your technician to check the engine mounts for excessive wear.  If a worn or broken mount is the cause of the condition replacing an afflicted mount and a wiring harness repair should cure this issue.

Lack Of Fuel Pressure Stalls Engine
Question 3
My 2005 Audi A4 with a 4-cylinder engine sometimes stalls and the check engine light turns on.  If I shut off the ignition and then restart the check engine light is off and the engine runs fine until the next time it stalls.
I took the car to a local auto supply store where a man checked the car with a diagnostic tester.  A code 89 showed up.  The man told me the fuel pressure regulator has a problem.  I wanted to buy a pressure regulator but he suggested that I take the car to a repair shop for more tests. 

Do you think the regulator is the cause of the trouble?  J.M., e-mail

Answer 3
Diagnostic trouble code P0089 does indicate trouble in the fuel pressure regulator circuit, but this does mean that the regulator actually has a fault.  It is possible there is faulty wiring, a pressure sensor might have a fault or the fuel pump might have an internal fault that causes stalling. 

While you are tempted to replace the fuel pressure regulator located under the intake manifold it is best that you make sure it is the cause of the condition before attempting the repair.  Guess work can result in replacing unnecessary parts and labor that can drain your bank account.   At this point consider the advice given by your partsman.  Take your car to an experienced technician who can accurately determine the cause of the trouble.

Headlight Lasts Only Two Days
Question 4
I own a 2004 Porsche Cayenne with a headlamp that apparently does not like me.  The bulb burned out in the right headlamp.  Thinking this would be a snap to fix I replaced it with a bulb that I purchased from a large retailer.  I installed it and it worked fine.  Unfortunately, it worked only for two days.  I returned to the store and purchased another bulb.  Again it worked only for two days.  This time I purchased a bulb from an auto supply store.  Guess what?  Two days later it burned out.  When I returned to the auto supply store the counter person suggested that I take the car to a dealer to have the system tested.
Is there something I am missing?  Could I be doing something wrong?  R., e-mail

Answer 4
By the time this issue is resolved you will be a Cayenne Xenon bulb expert.  You already have spent mucho dollars on bulbs.  You likely are not doing something wrong but it is important not to touch the bulb with bare digits or get dirt on it.  Fingerprints and dirt can reduce bulb service life but usually not down to two days.

The lighting system in your vehicle has a sensitive headlamp capsule and control unit that sometimes fails to perform when an aftermarket bulb is installed.  Since the bulbs are expensive, consider taking the vehicle to a dealer to have the system tested and visually examined.  A technician may find the system is operating as designed and installation of a factory original equipment bulb may end your woes.  Or, if you don’t want a dealer technician to work on the vehicle, purchase an original equipment bulb and cross your fingers it resolves the trouble.

Back Pressure Impairs Engine Power
Question 5
My 2005 Jeep Wrangler SE with a 2.4-liter engine and 75,000 miles has been a fun and reliable vehicle since it was new.  It hasn’t given a bit of trouble until now.  Several times a day when shifting from second to third gear the engine lacks power.  I push in the clutch to shift from first to second and the engine seems fine.  When I push in the clutch to shift from second to third as soon as I engage the clutch the engine bogs down. I can push the gas pedal all the way to the floor and the engine just slowly accelerates to my desired cruising speed.  It takes forever to accelerate and shift into fourth, fifth and sixth gears.

I took the vehicle to my dealership and an independent shop.  At both shops a mechanic checked over the engine.  They checked the fuel pressure, sensors and spark plugs but everything seems okay.  Both mechanics drove the vehicle and experienced the trouble.  The dealer mechanic checked some wiring in the engine compartment but could not find a problem.

I take great care of my car with oil and filter changes every 3,000 miles.  I follow the owner’s manual service schedule for everything else.  My Jeep is in great condition.  Can you help? T.C., e-mail

Answer 5
You love your Wrangler.  It will be well soon.  Ask your favorite technician to check for excessive exhaust system back pressure.  The catalytic converter may have failed and is blocking engine exhaust flow.  If this is verified, there is a good chance an emissions warranty at your dealership will cover the cost of replacing the part.

Operator Parks Vehicle Due To Mouse Scare   
Question 6
I think the motor for the heater in my 2006 Chevrolet Avalanche is making noise.  At first I thought there was a mouse in the truck.  I placed traps in the vehicle and didn’t drive until a mouse was found.  After 10 days when no mice were trapped, a friend checked the dash and glove compartment, but he did not find any evidence of a mouse.  He thinks the heater motor is making noise.

At times I hear a high pitched squeaking or squealing sound when the blower control is set to low speed.  Sometimes I hear the sound when making a turn.  The noise seems to be coming from the area of the glove compartment. 

Do you think the sound is from the blower?  Is it going to cost me an arm and a leg to replace it?  K.L., e-mail

Answer 6
The sound you hear is consistent with the failure of bearings in a heater motor and not a mouse.  Besides, if mice were in the vehicle they more than likely would jump on the dash or run across your feet while you drive.

Now that you are freaking out, the replacement of the blower in your truck is not major surgery.  Also, if you do a quick internet search you will find prices for a new motor can range greatly from $20 to $450 depending upon the source.   A factory original equipment motor is at the top of the price list so weight your options when selecting a shop to replace the part.  Most shops use an industry standard labor guide to determine what to charge to replace the part.  My labor guide suggests three tenths of an hour to replace it.  Be sure to compare labor, parts cost and warranty before deciding which shop is awarded the work.

Dr. Gizmo can’t wait to answer more.
Phil Arendt is a columnist, consultant and A.S.E.-Certified Master Technician.  Readers may send questions to Dr. Gizmo at P.O. Box 548, Cary, IL. 60013 or e-mail address drgizmo@drgizmo.ws. Check out his automotive information blog at http://drgizmo89.blogspot.com  ® DR. GIZMO © 1989-2012

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