91 LeSabre won't start

[mklmnade]

I have a 91 LeSabre which has had intermittent starting problems for the last few years. It has 177K miles on it and was my father's car before he passed in 2000. I have managed to keep it running since then, but the visits to the car repair shop in the last couple of years have me rethinking the value of hanging on to it. Within the last 10K miles, I have had the following replaced: alternator, timing chain, spark plugs, ignition wires, cam magnet/sensor, fuel filter, crank shaft sensor and the fuel pump (along with the fuel strainer, the wire set and replace/rewire the pump assembly). It used to only fail to start if the car was hot from running around town all day, after stopping & starting several times. If I waited for it to cool down, I could get it to start again. That problem seemed to go away briefly after the crank sensor and fuel filter were replaced. But a week after that repair, I had to have the car towed in. It would start, but then cut off...wouldn't continue to run more than a few seconds. No sputter, just nothing. It would sound like it was going to start, but just die. That's when the fuel pump and wire set were replaced. But it's not even 24 hrs. since that repair, and I could not get it to start today. Please help! I have a considerable investment in repairs up to this point, and I love the way the car drives and rides. I would like to continue to keep it as my second vehicle...any ideas what else I should have my mechanic try?

[Bassasasin]

Sorry you have invested so much.

Both fuel pump and ignition module/coilpack have a history of failing under specific temperature condiditons.
Never let the car run out of fuel. It will burn out the pump.

Try the coil pack first or should I say next.. usually can find one at a JY.
Pick up the Ignition module at the same time if you can.

The ignition module sits directly under the coil pack is next and a little more difficult to get out.
It is a bit more suspect since you said your Crankshaft sensor seemed to help for a while.



I agree on the comfort and own 3 Buicks now just because of it.

Of course its best to try to determine if your not getting fuel or ignition but the ignition module addresses both.

If you want to troubleshoot it just carry a bottle of cold water and drive till it quits when hot and pour the cold water over the coil pack and ignition module combination. Try and start it and if it fires up or fires much better, its highly suspect.

Just to know if the Crankshaft sensor was bad it would not try to start or sputter until it worked well again the coil packs will. The Crankshaft sensor stops the engine completely. Its usually quit or working. OFF or ON. The engine will not usually sputter or try to fire.


Good Luck

[Mickey#1]

Hi Mary - Like Bass said we need to know if it's a fuel or ignition problem.

It sounds like your mechanic changed the fuel pump then dicovered the pump wasn't getting power & rewired something. He should have checked for power & ground at the pump before replacing it. A common problem on these cars is corrosion on the ground bus. If the engine isn't getting fuel & he didn't rewire the ground then this is what to check first. Here's a pic showing the location of the ground bus.

[mklmnade]

Thanks Bass and Mickey! I will look into what you suggested. Sounds like I need to place some phonecalls to the local junkyards for some parts. For the record, I have not let the car run out of fuel since I have had it. Since the repairs I have had done recently (crank sensor and fuel filter), the sputtering problems have quit. It starts up strong, then dies without a sputter. The temperature of the engine doesn't seem to be a factor now in whether the car starts. I'll repost after I get the car towed and talk to my mechanic...may not be for a week or more...I'm still reeling from the last 2 weeks of car repair bills!!

[Bassasasin]

Did you say it starts and then stalls.. like in your driveway??
If so.. the security system allows for fuel pulses to continue to let a car start very briefly some models...
It will allow a brief start and about when you take your hand off the key it stalls..

Is this what you have?

Bass

[HotZ28]

IIRC, this particular car (91 LeSabre) had VATS, or PASSKey I security system, which would disable the starter circuit and injector pulse during an attempt to crank. PASSKey II - disables injector pulse after startup. PASSKey III - has a key and transponder module in the steering column and the PCM disables the injectors and the starter enable relay. PASSLock – (used on the 96-98 Buick Skylark and other GM cars & trucks) disables the injectors approximately 1-2 seconds after startup. It has no effect on the start circuit!

When diagnosing security related problems, you should first look for a flashing or illuminated “Security” light. This is an indication that the system is disabling the starter. Remember, even if you supply an alternant power supply to the starter solenoid, the vehicle will not start, because the ECM will shut down the fuel injectors until it gets the proper signal from the decoder module.

First you need to determine if you have spark and fuel when it stalls! If no spark, as Bass stated in post #2, the ICM should be the next part to be tested or replaced! Also, be sure to check & clean the ICM terminal and apply dielectric grease before reconnecting the terminal. This could even be an ECM problem, but not as likely as fuel/ignition problems. IIRC, the 91 used the Magnovox ICM with the ignition wires coming out both sides. They were especially prone to failure! Click Here for more info on that subject!