92 lesabre running bad after warming up, can only drive a little ways

[donniey]

My 92 Lasabre after driving for about 10 miles starts running rough and sputters. after letting set for 10-15 mins will go again. starts find cold , runs find cold.

[comp]

do you know how to do minor repairs? if so open hood and check for
obveous things, air filter ,vac.lines things like that.. do you like in the cold? fuel dryier... has it started slowly,or just all at one time? after a fill-up, etc, more info after looking under hood

[donniey]

Hey comp
I've tried alot of things, spark plugs and wires, vac hoses, fuel pump, new air filter. I have it at a garage now I got fed up. They can't seem to find the problem either.
The car starts fine runs fine for about 30 mins. then the engine starts missing badly and the longer I run it the worst it gets. After cooling runs fine till the next 30 or so mins.
Thanks, If I find out will be glad to post.

[Freshavionics]

Funny thing I have a 92 lesabre that does the same thing. I have had to a shop 3 times, and they can find nothing. I have had the ignition module replaced, coil replaced, computer replaced. Have found that the center coil stops firing when this ocurs, have swiched coils and still the same thing, center coil quits firing. Beginning to think this is a harness problem from computer to ignition module however have no wiring diagram. had this problem last summer and fall and it ran perfectly all winter, however now that is warming up here in South Dakota I get about half hour drive time out of it. frustrating. Any one have any other ideas?

Mark

[hellfirebob]

Ok this sounds like my problem.

I am having problems when the car warms up after about 10 min then it will start to back fire through the intake.

Parts replaced

1. camshaft sensor
2. crankshaft sensor
3. computer
4. fuel pump
5. pulled the converter
6. tps sensor
7. cold start sensor
8. egr valve

So the car will not give any codes at all , and when it gets warmed up
it will run ok as long as you dont try to get into it, if you push on the gas too hard it will stumble and back fire through the intake. The car has about 207k on it and well taken care of.
I Have to ask maybe some one knows , the book tells you jack but if the magnetic pickup falls off the timing gear will it toss a code? Also from the way it acts it sounds like a timeing problem but could be coils so I am at a delma on what to do next..

Please help if you can Thanks In advance

[Lasota]

I had a similar problem after warm up, it ended up being a bad ground on the ignition module. It was messing up the signals from the crank and cam sensors.

[hellfirebob]

So how did you fix , did you just pull the coil block off and brush it off with wire brush ?

[hellfirebob]

So I too the crank shaft position sensor off and check for the magnetic pickup and it was there and working great but after further checking way too much play in the chain . I will replace the timing chain and geers since it has 207k on it. I did wire brush under the coil assembly and it was bad but that didnt help...

Thank any more info any one can give. I will update it the chain clears things up.

[Lasota]

I cleaned off everything all the way back to the engine block. Wire brush and fine grit emery paper till it was shinny.

[Freshavionics]

Finally got mine fixed. As it turns out the Crankshaft position sensor mounting bracket had a tiny crack in it (barely visable). I would have never believed it, as I would have thought that it would have killed all the coils, however It seems to have fixed my problem. I had in the past been able to duplicate by leaving hood down and let idle for about 30 minutes (very predictable), then center coil would stop firing all together while the other two would continue firing, let cool 10 min and it would run great again. I let it run for 2 hours yesterday and it kept on ticking. I can only assume that due to the heat built up in the engine compartment the crack would expand thus changing ever so slightly the crank position sensor.

Hope this helps

Mark

[Freshavionics]

FYI had friend of friend at GM dealership, provide this info as he initally said that it was impossible just one coil to quit firing given all that has been done, he then looked up some posts that I can only assume are other GM dealerships and said he found 5 with this same problem, only one provided a solution to his problem and that was the one with the crack in the crank position sensor bracket, this is what seems to have cured mine as well.

Mark

[Freshavionics]

almost forgot, replaced all the plugs at this time too, cant see where it could have fixed the problem, however this was done at the exact time that the bracket was replaced.

Mark

[kray]

[quote=Freshavionics]almost forgot, replaced all the plugs at this time too, cant see where it could have fixed the problem, however this was done at the exact time that the bracket was replaced.

Mark,

My dad has a 93 that just started this problem yesterday. Can you tell me where the crankshaft position sensor is located? His problem sounds just like yours.

thanks,
Kevin

[Freshavionics]

Kray,
This mounted behind the harmonic balancer (very lowest pulley your belt rides on). I had a retired mechanic change mine as he had all the tools needed and has changed many. If you do not get positioned (aligned just right ) the and the sensor makes contact with the vanes on the rear of the harmonic balancer you will more than likely end up with a broken sensor. He treated me pretty good on this 100.00. I guess what im saying is I would let someone that has done this before tackle this job. This may not be your problem, but before I would throw a 270.00 ignition module at it I would definatly check this out. Yours may be as simple as a bad coil, I would swap positions of coils to see if the loss of spark follows the coil or stays on the same position(cylinders). you can get a spark tester cheap at auto store and place in line with with the spark plug wire to verify what coil is not firing.
I picked up a book (by Haynes) at the parts store ($15.00) with the wiring in it as I was beginning to think it was wiring however after seeing how the system worked on the diagram it no longer made sense that wiring could cause my one coil to quit firing.
Anyway I would start by checking out the coils as they are very easy to swap.

Good luck

Mark

[bbpsingh]

Yesterday I took out my car EGR valve and cleaned with Carburetor cleaner spray.
Put back. Car started but the codes 24, 63, and 65 stayed.
Took out battery cables for 30 min.
Put back cable. No codes at all.
However, car starts with vibrations ( rough). Have to keep gas pedal down to keep running.
I am still on Driveway.
Any advice!!!
Bruce
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