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Friday, May 10, 2013

Dr. Gizmo Column

 "Dr. Gizmo"
By Phil Arendt
 

Melted Wires Stall Engine
Question 1
The body and interior of my 1993 Eagle Vision are in great condition but recently an issue developed in the wiring.  I don’t drive this car much but a week or so ago when the weather was warm I took it out for a spin.  I was at highway speed when suddenly all of the dash lights turned on and at the same time I heard a high pitched squealing sound.  The car stalled.  This resulted in a tow back to my home.

At home I found wiring along the passenger side of the engine compartment melted.  Many wires were bare, touching each other and sort of melted together with melted insulation.  I separated the wires with a razor blade.  Once the wires were apart I was able to start the engine and all of the warning lights were off.  Also, I did not hear the squealing sound I heard before. 

What do you think caused this problem?  Should I replace the wires?  There are about 20 of them.  Is it okay just to wrap the wires with electrical tape?  L.L., email

Answer 1
You are lucky that the engine control module survived the event as it might be the part that made the high pitched sound.  I can only speculate what caused the wiring to short but maybe a hungry mouse caused the chaos.

As for repairing the wiring with electrical tape, you could but by the time you wrap enough tape around each individual wire you probably will end up with a bundle about the size of a 16 inch soft ball.  To do the job right it would be better to replace the burnt mess with the same color coded wires and appropriate connectors, preferably heat shrink self-sealing connectors.  This makes for a long-lasting and weather-proof repair more consistent with the original design and it will last for years.


Troubles Might Be Related
Question 2
I have two problems with my 2000 Chevrolet Blazer with 129,000 miles.  The four wheel drive does not engage and water leaks in on the front passenger floor.  My truck is in good shape.  I have followed the factory maintenance schedule for all services so I plan to keep the vehicle for a few more years. 

I went to a local repair shop where I spoke with the manager about the troubles.  He said his technician will need time to locate and repair the water leak.  He could not estimate how long it would take because the water could be coming in around the windshield or maybe even the dash.  He told me that there may be one or more problems with the four wheel drive and only tests will determine what’s wrong.  Due to limited time I did not leave the vehicle for repair.

Do you know what causes these problems?  R.K., email

Answer 2
The two problems could be related.  The control module for the four-wheel-drive is in the passenger side kick panel.  That is the trim panel on the side below the dash between the firewall and door.  Water dripping onto the wiring and components in that area certainly could cause lots of trouble.

It’s time to leave your vehicle for repair.  Once the source of the water leak is determined and repaired ask your shop to consider checking the components behind the kick panel for water damage.

Growling Transmission Might Be Symptom Of Big Trouble 
Question 3
When cruising in my 2004 Chevrolet Trailblazer I hear a growling sound.  I went to a repair shop to have the noise diagnosed.  The technician said it is coming from the transmission.  He does not do transmission repairs but can install a remanufactured unit. 

My truck has 103,000 miles and it’s in great condition.  I have not had any trouble until now.  I follow the maintenance schedule in my owner’s manual.  I trust my repair shop.  They flushed the transmission flushed about a year ago. 

The transmission works fine.  Is it absolutely necessary to replace it?  V.C., email

Answer 3
With 103,000 miles it is possible that any work deep inside the unit will likely lead to an overhaul.  At this point it is likely normal wear of clutches and many other parts will require replacement not to mention seals will definitely need replacement.

For peace of mind, seek the opinion of a shop that specializes in transmission repair.  Weigh your options once you have a second opinion.

Recent Purchase Needs A Timing Belt
Question 4
Recently, I purchased a 2003 Dodge Neon SXT with a 2.0-liter engine and automatic transmission.  The car is in great condition despite having 137,000 miles.  The former owner gave me copies of all his service records and it appears he took good care of it with frequent oil changes.  Also, before I bought the car the seller and I went to a repair shop to have the car inspected.  A mechanic checked it over and determined it is good condition, but he suggested that the timing belt might need replacement.  The owner was not sure if this work had ever been done.  His records did not indicate the belt was replaced.

The problem is I don’t have an owner’s manual so I don’t know if it is necessary to replace the timing belt.  Is it?  Also, is there a place where I can buy an owner’s manual?  L.F., email

Answer 4
Congratulations on your recent purchase.   Also, you deserve a commendation for going through the proper steps of having the vehicle examined before purchasing it.  Many people don’t.

As for replacing the timing belt, according to the factory maintenance schedule it should be replaced every 105,000 miles.  Your car is due for a replacement since the previous owner does not have a record of having the work done. 

As for where you can purchase an owner’s guide, you might consider going to the Dodge website at www.dodge.com/owners/manuals to order it on line or you could ask your local dealership parts department to order it for you.  Also, sometimes used owner’s guides can be found at flea markets or salvage yards.  Once you have the publication, refer to the severe service maintenance schedule.

Apply The Brakes And Radio Shuts Off
Question 5
When pressing the brake pedal in my 2005 Chrysler Town and Country van the radio and heater blower quit working.  When I release the brakes these items turn back on.  I went to my repair shop where a mechanic advised that it might take several hours of probing to find the cause of the trouble.  He did a diagnostic test of the engine computer but he did not find any trouble codes.  He says his next step is to check the wiring.  This might take a long time. 

Do you have any suggestions?  H.B., email

Answer 5
I guess you shouldn’t apply the brakes.  Problem solved.  All kidding aside this likely is a wiring problem. 

A check of wiring schematics and a professional website may have found a possible clue to the trouble.  Ask your technician to consider checking the ground connections near the left “B” pillar.  They may be affected by corrosion.

Knock Sensor Does Its Job 
Question 6
The check engine light is on in my 1996 Toyota 4Runner.  My shop did some tests and found codes related to problems in the knock sensor.  They replaced the sensor but the trouble lingers.  They checked the wiring but no problems were found.  They also checked the sensor because at first they thought the new sensor was bad but it passed tests.  They tried another sensor but this did not fix the trouble.   

What else would cause the trouble?  D.N., email

 
Answer 6
Generally, knock sensors detect knocking sounds in the engine.  Sometimes a lean fuel mixture, improper timing, low octane fuel or even carbon deposits cause knocking.  It’s also possible there is a condition such as excessive wear of bearings that might be the cause of the trouble.  Since I don’t know how many miles are on your vehicle it’s possible the mileage exceeds 200,000.  If so, excessive wear might be a consideration. 

Ask your favorite technician to consider these possible suggestions.

Thanks for all of your great questions.  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 mailto:drgizmo@hotmail.com 04/22/2013 ® DR. GIZMO © 1989 - Present

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