can you help i have a 1994 buick skylark 3.1 v6 car starts and runs for about 15 or 20 min then stalls but when it cools down starts right back up for a few min then quits and won't restart until it cools down have replaced the fuel pump the fuel relay ignition module and the crank shaftsensor and still no fix does not idle rough and when it quits does not stumble or surge almost like you have turned the key can u help and has a 146000 miles on it

They had some issues with bad ECMs acting that way but you first need to perform standard "no start" tests.


All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.



Once you have determined which of these functions has dropped out,
you will know which system is having the problem.




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checked the fuel pressure showed 45 pounds running when off fuel pressure drops to about 35 36 pounds pulled a plug out and connected to wire layed on the top and car started

You'll have to wait until it dies again to finish testing.




78 Corvette Pace Car For Sale-18k mi orig-Florida

just a odd question if the spark plugs are old and preety well corroded would it cause the car to stop even though it does not sound like it is miss firing the plugs have been in it for who knows how long but noticed they were white with corrosion and black tips just a thought

Those are things you should have done long before you start looking for an issue like this. They'd have to be pretty bad to cause these issues but don't ignore them.




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thanks for all the help found the computer was fried but why and how

That would be the 6 million dollar question..........

Some techs will tell you that there is always an external cause of an ECM failure but I don't totally buy into that. Some computers were just designed and built substandard. As I said in my first answer, those vehicles had a lot of problems with computers and failures were pretty common.




78 Corvette Pace Car For Sale-18k mi orig-Florida