No Restart when Hot 3.8v6

Hello All. I googled this subject before writing now, but search results didn't quite fit- so I'll come to you with my situation. thanks for any help you might offer...
1999 Buick Regal 3.8 (not supercharged)......smooth running at all other times.
This car will not restart when hot (say driven plenty on a hot summers day-80f) Starter turns engine over-no problem there. 1st restart attempt engine fire and stumbles badly-like was once called vapor lock subsequent attempts- no hint of firing up. (starter turning engine over just fine) Long cooldown period required...2+ hour wait and it starts and runs fine. What do you think????
Here is one caveat. I drove 200 interstate miles, stopped mid afternoon-no restart for 2.5 hours as described above. Engine AND ambient temperature where cooler when restarted. Then I drove 200 miles home arriving in cooler evening temps....car restarted fine??? I was wondering about the cooler ambient temp and couldn't duplicate problem. Engine was just as hot(looking at the gauge) but ambient air 60f not 85f. Thanks again for any help. John
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First thing to look at is there any spark when the no start occurs, also using a scanner , do you get an rpm signal when cranking and no spark. The answer to these questions will lead to the next steps. Such as a bad crank sensor or ign. module. There are other possibilities but for diagnostic purposes this is a starting point.

help
just
cooler
hot(looking
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Darby OGill wrote in alt.autos.gm

I am surprised that you couldn't find this. This is a fairly common problem. Heat related failures occur quite often, especially with newer cars with electronic components. Most likely components are the ignition coil pack, module or crank sensor. When electronic components start to go bad, they often fail under more extreme heat. And when you drive your car, then stop and shut it off, the heat no longer is being removed from the area around the engine. So it just builds up, and then slowly goes back down. Eventually it cools down far enough to allow the parts to start working again. And when the ambient temperature is lower, the lower the temp under the hood, and the faster the heat trapped will dissipatate.
--
Dick #1349
Damn it . . . Don't you dare ask God to help me.
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Thanks David and Dick for your responses......David, that makes sense. I can check for spark. Can you advise me how to check for the rpm signal? I guess that this checks the crank sensor? Can I do this with a VOM? .......Dick, I could find others who had various heat related problems and possible sources ranging from ignition module to fuel pump. I didn't find any diagnostic suggetions for the driveway mucker.

help
just
cooler
hot(looking
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If you can buy or borrow a set of "noid" lites you can check injector pulse at the the individual injector connector harness. this will confirm crank sensor operation for the most part, also could be the pcm fails when hot, try locating it and tapping it firmly with a medium size screwdriver handle, and see if any reaction to start. You may need some experienced help with this process. PCM's are usually not problem with these later GM cars. A scanner of course will tell you if the pcm sees a crank signal, which goes to the ign. module, then the pcm.

fine.
afternoon-no
John
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Electronics stores sell " circut cooler " a spray can of a refridgerant that rapidly cools parts like capacitors. Squirt suspect components that won't run hot.
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The ground circut should be beefed up on older cars. This may / may not cure problem.
GM cars have thickly painted alternator brackets, the ground fastens with a sheet metal type screw. Unfasten ground, and move it to block itself, clean connection points. For the ultimate, use a stainless steel bolt. To be even safer, run an old battery cable from frame to block. This will probably brighten your taillights, which dim on older cars.
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