Older Pontiac stalling mystery SOLVED

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I have a 1989 Pontiac Grand Am, Quad 4 motor, four door. It was given to me a couple of years ago 2002 by my father. Of course, being a guy in his 80s, he babied the car and as these older gents do, he bought a new car.
I needed a car and took the Pontiac. It ran superb for two years. I even drove it to New York City from Buffalo 410 miles one way , drove it back and forth a number of times to Toronto 90 miles one way, and also used it every day the way Americans love to use their cars.
Slowly, over time, I have been experiencing a stalling problem. Here's what happens. I drive the car for a few miles, maybe 5, maybe 10. Things are fine until something heats up, and if I have to slow down at a red light or stop sign, the car sputters and stalls. I could drive the car for 100 miles on a superhighway and have no problems, but once I have to deccellerate, it'll stall. The situation is worse in hotter weather. The car rarely stalls in colder weather. I love January.
Anyway, after the car stalls and sits for anywhere from 7 to 17 minutes, it'll start right up and I can move along to my local destination. But it will eventually stall again as I deccelerate. If the car sits for an hour or so, I can drive further than if it sits for 10 minutes.
I have done huge research on the problem. Huge. I've taken it to mechanics. I've had mechanics who won't work on it. Some think it might be a solenoid issue.
I've seen comments on myriad boards about others having this problem and it seems to be a mystery to most. The real tragedy is that GM has made a line of cars that have this problem. Anyway, after tons of research, here's the deal, and I hope this helps any of you out.
The car is experiencing one of two serious problems. The first may be that a heat shield protecting fuel lines or filter may have shifted or broke or just eroded away, and this is causing fuel in the line to vaporize, thus causing the stalling. That's one theory, but I really don't subscribe to it.
The theory I like is this: The car is having a serious Ignition Module (IM) failure, which may also be linked to other electrical malfunctions. The IM needs to be replaced and you might want to replace, probably should replace, the Crank Sensor.
The cost is steep. To drive it onto a Pontiac dealer lot is a minimum, no questions asked, $75.00 for one hour of mandatory diagnostics, even though you know it's an IM problem. The diagnostics could take two hours. Hopefully it won't take three. The mechanics will test every aspect - they have better equipment at dealers than do regular mechanics, and determine the exact point where fuel is not getting into the line and what is causing it it to choke or vaporize - certainly the IM. The cost of the Ignition Module is around $200. The crank sensor is around $30. So with one hour of diagnostics, and the parts, we're talking $305 without labor and any other parts.
I hope this helps you out. As for me, I was just given, by a friend, a terrific 1993 Nissan Altima with 181,000 miles on it and it's good for another 75,000, I'm sure. Oh, I know you're probably wondering, why do people keep giving this guy cars? I guess I'm just a likable guy.

posted by  Dante Estlin

As shown in another thread I'm also looking at a similar problem on an 89 Grand Am. Codes suggest it's the IM particularly as the crank sensor is new. It's now at the stage where it never starts. Interestingly I had a similar problem on an 88 T-Bird which turned out to be the sensor in the distributor. (what the dealer called a 'stator'). :doh:

Worst thing about doing the Grand Am IM yourself is it's located between the motor and firewall so it's a difficult skinned knuckle job. :ohcrap:

Mine gives a repeated trouble code of 12. Pulling the codes is real easy and to put a switch in to read em when it fails is a simple job as the connector is right in the front of the dash. :clap:

posted by  HighWayMan

Ignition module is exactly what I would have suggested...

posted by  DodgeRida67

just got through dealing with the ignition module on 1990 Century 3.0L V6. At least Ford put theirs on their DIS systems on the fenderwell (at least on my 92 Crown Vic) where you can get to it

posted by  tbaxleyjr

If you haven't figured it out already, its the TCC (transmission clutch control) selenoid. I almost guarentee it to the point that if that doesn't solve your problem I'll pay for the cost. ALMOST. See, i have the same grand am, the same problem, blah blah blah. The problem is the selenoid goes bad, so after cruising for about 15 to 30 mins, the selenoid stops working, and the clutch is not engaged when you stop. I'm talking about an automatic, YES there is a clutch in an automatic, it just AUTOMATICALLY engages, unlike a manual. Anyways, replace the selenoid, i found someone who would do it for 175 bucks. thats the cheapest, others wanted 200+. So its not exactly cheap, but if you can do it yourself, the part is about 25 bucks. Now thats cheap. Otherwise, pony up the cash. I had two cars with this problem, a 91 grand am and an 89 cutlass ciera. Theres no way I'm wrong on this.

posted by  rkoz1216

I'm talking about GM cars here though, i have no clue about any others. Its the N cars that have these probs.

posted by  rkoz1216

w-bodies and j-bodies have it, too. it's the trans, not the body...

posted by  dodger65

Yeah i knew it was the trans, cuz thats where the TCC is. I didn't know it was the other bodies too, but that makes sense since my cutlass ciera had that problem, and wasn't an N car.

posted by  rkoz1216

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