Question about 1991 Pontiac Firebird

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1991 5.7 TPI trans am wont start back up after warming up

I have had this car about two years. It is a 1991 factory 5.0 TPI automatic car. I purchased it in perfect running condition.The 5.7 block was installed before I purchased the car and ran just fine. (to date the engine-the valve covers have the homd down screws in the middle of the covers.) Last year it started this problem- I would be driving and it seemes to stall out when it warmed up- then, after new distrib,cap,rotor,plugs,timing chain,fuel pressure regulator, new plenum gaskets, remanufactued computer and PROM-and much more- I still cannot find this problem. I also removed the exhaust from the Cat back (needed to be replaced and the Cat would glow RED when I allowed it to sit and run before I shut it off-so I thought maybe the cat was clogged but I removed it and still the problem persists.)
I have NOT done anything within the fuel tank but it has about 45-50psi at the fuel rail up on the injection. I checked the injectors with a test light and they all SEEM to be working-
You can start the car-it will run choppy and will sit and idle all day long-(correct temp. and all)
If you sut the car off when it is warm- It WILL NOT RESTART at all.-seems to be electrical??


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  • s60six May 11, 2010

    check the ignition timing and the firing order



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This is my own take on your problem, i don't think thats enought pressure from fuel pump, thats pressure you get from throttle body injection. I believe fuel injection should be around 60 psi. Just a few pounds below that it won't run right.

Posted on Feb 09, 2009


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