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Old 06-15-2017, 06:32 PM   #1
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Default 3.8L HARD START WHEN HOT

I have a 1996 firebird with a 3.8L V6 that starts hard when the engine is warm and shut off for 10 - 15 minutes. fuel pressure is 45psi key on, 42psi at idle and 36psi when key is back off. There is no black smoke when it starts and the pressure regulator is not leaking. I installed a used ICM and have the identical problem.
Any suggestions? It runs fine other than that and it will start it just cranks for a long time when it is hot. It has 135,000 miles on it.


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Old 06-15-2017, 07:33 PM   #2
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Check your IAC valve. Could be needing cleaned, or replaced.
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Old 06-16-2017, 05:55 AM   #3
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Well, it could be the IAC, but wouldn't that cause other problems, like high/low idle, stalling at stops? What bugs me is it runs ok after a delayed hot start....

Could pull it, clean the passage and pintle and see if this corrects it.....

This reminds me of the old setup when we had the oil pressure sensor in parallel with the f/p relay.....if the relay was bad, you would have an extended crank, until the oil pressure built up, but that would happen hot or cold, and this engine does not use that setup anymore...

Have you checked for codes?

If this happens all the time, spray carb cleaner into the intake, then try to start after the car is warm and sat for a few minutes......if it starts right away, when was the last time the fuel filter was replaced?
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Old 06-16-2017, 03:15 PM   #4
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Default 3.8L HARD START WHEN HOT

I have thought about the IAC valve but, I have no other issues like, under run or stalling, high idle. I will clean it and see if it makes a difference.
I have not checked for codes because it hasn't tripped a code in 3 - 4 years but, I will double check. I have not changed the fuel filter since my fuel pressure is in good shape. The fuel psi regulator does not look like it is leaking but, the regulator is on the back end of the fuel rail, under the dash, so I can not smell the vacuum line to see if gas is in it. Only a visual test. It also takes about 3-4 hours for the fuel psi gauge to drop to 20psi with the key off.
Thanks for the help and I will let you know how I make out with the IAC.


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