Stalling Problems
Hey home mechanic, says Mr. Karmann of Toronto, Canada!
The following is a little story about stalling problems that some of your readers may find helpful.
Mr. Karmann has worked in the automotive business as a technician, we used to call them mechanics, for over thirty years and the one thing he found is no matter how much you think you know there is always more to learn, especially with technology moving so fast.
Here is a little story about a customer who came into our shop with a complaint of her car stalling. The car was a late eighties model Buick with four cylinder, automatic and throttle body fuel injection. Two of our young tune up techs, who shall remain nameless, had a go at solving this ladies problems. At first the stalling problem would not show up but the car was scoped and a fault code check showed no fault codes. A minor tune up was recomended along with an injector flush and cleaning of the I.A.C. motor, which controls idle speed and can become contaminated with carbon. After these repairs and much money spent the customer picked up her car only to return in a few days with the same stalling complaint.
Again a fault code check showed "no codes" and the car would not stall on a road test. This time the car got a rebuilt computer and road testing again showed no stalling. To shorten this sad tale, the customer, by the way was going around the bend at this point and who could blame her. The customer was given a loaner vehicle and I was asked to drive the car home one night to see if it would stall. I only live about ten or fifteen minutes from work so guess what, again no stalling. The problem finally showed up with myself and the service manager going on an extensive drive which lasted about thirty minutes at various speeds, we were almost back to our shop and thinking this customer was crazy when the car not only stalled but on start up stalled again and could not be moved. After cooling down for about five or ten minutes the car started and ran fine all the way back to our shop.
The cause of this problem has probably been already diagnosed by any tech reading this, a little thing called the T.C.C. solenoid caused this ladies problems. A T.C.C. is in plain english a solenoid that locks up the torque converter in your transmission to give you better gas mileage and is found on most cars of today. This lock up must occur with the car fully warmed up and at higher cruising speeds or stalling will occur. The T.C.C. is located in your transaxle and has a wiring connector in plain view and can be disconnected and the car run like this without causing any problems other than a little higher fuel consumption for a few days and if your stalling problem disappears voila problem located.
Moral of this story; you, as a customer should give as much information as possible to the shop working on your car. The shop should listen closely to the customers complaint to try and repair the problem with minimal aggravation for all concerned. Most customers do not go to a repair shop unless they really have a problem, maybe if we'd have asked the better questions the problem could have been found sooner. The key in this case was stalling after a good drive, or only when hot. This problem can and will set a fault code but didn't in this ladies case. Fault codes are very helpfull but are not always present when you are checking out a car. We have had several of these same type problems on late model G.M. cars since but I'm sure it is happening on other models as well. We now will disconnect the T.C.C. solenoid and have the customer drive it for a day to see if stalling is corrected when no fault codes can be found.
We won't get caught like this again but I wonder if this lady has lost confidence in us. Her old computer was re-installed and refunds made to her but we sold her a tune up and other repairs that didn't solve her problem. COMMUNICATE WITH YOUR TECHNICIAN the questions may sound dum and boring to you but may save you time, money and a lot of agravation.
Transmission Going In & Out
Tom had an '85 Firebird whose transmission (in warm weather only) would constantly go in and out of torque converter lockup when climbing the slightest grade. Tom took it to several dealers and was told that he needed a transmission overhaul - "they all do that when they need to be repaired."
The transmission eventually failed and Tom had it rebuilt. The rebuilder told Tom that he did not believe that the rebuild - although needed, for Tom had lost high gear - would take care of the problem that was described. And the rebuilder was right. The rebuild occurred in October, and months later, when the weather warmed up, there Tom was - in and out of lockup again!
Tom returned to the rebuilder and he road tested the vehicle, and it went in and out of lockup for him, too. The rebuilder said that he believed he knew what the problem was. He noticed that the speedometer needle tended to flutter at speeds under 40 mph. He also told Tom that the car's computer received a lot of information - including vehicle speed from the speedometer head - and that it fed signals to the transmission. Since the indicated speed was varying wildly, the computer was telling the transmission "Its O.K. to lock up, no it isn't, yes it is, no it isn't, etc." The rebuilder replaced the speedometer cable (the entire assembly, not just the core), and the problem was immediately resolved.
