Won't restart when engine hot


Old 06-09-03, 05:59 PM
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Won't restart when engine hot

Thanking you in advance.

My 92 Buick Riviera (auto, 3.8 litre) will not restart once the engine is hot. If I start the engine cold, drive for 5 or 10 minutes, no problem restarting. If I drive or let idle for more than say 10 minutes it will not restart. If I then let the car cool for 45 minutes it will restart every time.

The car is cranking fine it is simply not getting gas because when I have released the fuel from the nozzle in the engine the fuel line will run dry but the fuel pump will not kick in when I crank it again.

It almost seems like a vapor lock however, when I had the car in the bodyshop they put it in an oven at 140 degrees and the same problem happened even though the engine was cold before it went in.

There are no engine codes showing and a diagnostic showed nothing as well. The problem began this spring once the outside temp got back above10 degrees celcius.

Any direction will be welcome.

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Old 06-09-03, 08:33 PM
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it's pretty obvious that something is getting hot and causing it to not start, if it was my car and it had no codes as you say, i would check for spark at a spark plug wire when it doesn't start, this will narrow your search between fuel or spark, if you have a good spark that will jump at least 3/8" while a friend cranks the engine, from screwdriver to valve cover(with NO FUEL PRESENT, or you will quickly solve all your problems as you call 911) if you have it(spark) spray something flammable into the open throttle body for about 3-4 seconds (brake parts cleaner, wd-40, gum-out...)reconnect the air ducting and the car should run for about 5 seconds(likely-fuel pump, relay,wiring. not likely-all 6 injectors)further tests for this.
if you have no spark, short of a trip to the library(my library has all the mitchell manuals and are pretty thorough when it comes to a no-start condition) it's time to get creative with a hairdryer. with the car cold(able to start) try heating up the crank sensor(i think right behind the main crank pully--not positive on that car) or the ignition coil module(under coil pack) to the temp as you said of 140F until the car won't start, you could even try to heat the ecm(computer) as that is not out of the possibilities

you don't have vapor lock with fuel under about 40 psi

let us know what you come up with
Old 06-09-03, 09:34 PM
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If you start the car cold, will it continue to run as long as you want it to, or does it run a certain length of time and die?
At this point, though, a spark tester and fuel pressure gauge are in order.. See if you have spark once it dies (or is in the no start stage) and see what the fuel pressure is.
Old 06-10-03, 10:20 AM
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Thumbs up

I agree with MSArgent.
Old 07-04-03, 08:42 AM
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Thanks for the suggestions.

My Brother removed the fuel pump and hooked up 12 voltz and no power. The pump was the problem, but that doesn't explain why it worked when cold.

This is the third replacement fuel pump that has been put in the car, all in the past 5 years, obviously the parts were garbage or else I'm doing something drastically wrong.

Thanks again,

Old 07-04-03, 10:11 AM
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Use AC Delco pumps in your repair. Better quality and worth every penny over poorly made aftermarket ones.

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