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Q: Engine Stalls after driving short distance or idle, will then crank but not run on 1993 Buick LeSabre

This has been an ongoing problem. First it appeared the engine would not run when it was hot. Was told it was the ICM so that was changed out. After the ICM swap, the car would not run cold or hot. Was told a shorted Cam sensor would cause it. Swap out the cam sensor and car would then crank and run but the return to the stalling after idling. Was told the crankshaft sensor could be bad. Replaced the crankshaft sensor and drove the car six miles when it stalled on me. Towed home, the next day the engine started and ran, turn it off. That evening went to move the car and it would crank but not start.

The next morning the car crank and started, noticed smoke at the EGR valve, thinking electrical, turn engine off, checked EGR wiring, found nothing, attempted to start car it would not start. Thinking stuck EGR valve, I removed the EGR valve and disassembled it. The solenoids did not appear to be sticking and there was not a lot of build up of gunk; just normal exhaust residue. I cleaned everything and reassembled the EGR valve and installed it back on the engine. I had removed the battery cable to clear out the code where I unplugged the camshaft sensor. I started the car and it ran rough for a bit but then smoothed out. As I was standing by the car it would stumble a bit at times and I noticed the serpentine belt tensioner was jerking and I could hear a bearing squeal at times. I turned the engine off to check the tensioner pulley and I could feel when turning it that the bearing is starting to go.

I then started the engine, or attempted to start the engine and it would not start, it would turn over and appear to fire but not run. The engine had warmed up a bit but not hot; I could place my hand on the radiator without it burning me. I tried spraying some starting fluid into the intake connector tube (through a split; will need to replace it later) and attempted to start the engine without any luck. It would be nice if I had a helper but I don't.

So I decided to let it sit a bit to see if it would run after cooling a bit. I hooked the fuel pressure gauge to the fuel rail and later started the car and it ran fairly smooth, the RPMs did change a bit, slowing a bit and the fuel pressure as the engine was running was approximately 39 psi. The car only ran for a short time before it started stumbling again and I noticed the fuel pressure gauge swing up to around 50 psi and when the engine died the fuel pressure stopped at 46 psi.

To recap, the coolant sensor, the ICM, the camshaft sensor, and crankshaft sensor have been replaced. The Mass Air Flow sensor was cleaned and the TPS was checked with an ohmmeter and appeared to not have any opens, the ohmmeter needle swung continuously as the TPS was moved through its range.
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The fuel pressure regulator applies vacuum to the fuel pressure regulator when the engine stalls the vacuum goes away and the fuel pressure should remain in the line and be higher and if you snapped the throttle with the engine running vacuum would go away and fuel pressure would rise momentarily. Under load/full throttle on the road fuel pressure should be at the higher figure as well. Pressures sound OK. The problem could be caused by many things hard to say without being able to do some tests.I wonder if you got a good computer r even just bad wiring. Any intake vacuum leak is going to supply "bad" information to the computer as to how much fuel the engine needs to run. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate
If your car ends up in a repairshop and they are stumped, There is a professional service called Identafix. They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. Your auto repair shop do all their diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If the repair shop that are repairing your car are stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base.
I am beginning to suspect the computer is malfunctioning after being in operation for a while. The day it started and ran in the morning but not in the evening the car had been shut up with windows closed allowing the interior of the car to heat up. The computer is located under the dash behind the glove compartment in a confined space. If possible, even if I have to remove the glove compartment, a test would be to run the car until it quits and then use electronic cooling spray and see if cooling the computer down allows the car to start and run again. It could be bad solder joints that are opening when the unit gets hot from being in operation. I have read a report that the engine computer on this model is known to fail. This car is 18 years old with, as far as I know, the original ECC/ECM. My concern with replacing the ECC/ECM is that I need to use my old PROM and if the PROM is bad then a reman ECC/ECM is still not going to work. Oh, I forgot to mention that no codes have been set for the problem I am experiencing (OBD-1); codes checked by shorting OBD-1 connector and counting flashes on the check engine soon light.

I have tried checking for vacuum leaks. I read where a leaking brake booster has been known to cause stalling when depressing the brake pedal. I unplugged the vacuum hose to the brake booster and plugged the end but the car would not run. I see no obvious broken or split vacuum lines; besides, the engine will start and run without problems until an amount of time has passed, or six or seven miles of driving. A leaking intake is always leaking, a broken vacuum line is always broken. We can eliminate those things that are constants. This problem seems to be related to either passage of time, or temperature.
Hey Kimberly W, I'd like to know what the problem turned out to be, my roommate has the exact same problem with his 1989 Ford Bronco with a 5.0. It will start and run fine for between 6 and 7 miles and just quit. Almost right down to the same traffic light on the way home from work. After 20 min. or so it'll start back up.
In my situation the first time I had this problem I had replaced ICM spark plugs cam sensor and crank sensor. I had a code for a misfire and it all turned out to be my timing chain the whole time. The second time I had this problem I suspected the fuel pump or MAF sensor. Turned out to be a ground cable that was not attached correctly.
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