C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

1986 To much fuel pressure

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Old Jul 12, 2007 | 04:33 PM
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Default 1986 To much fuel pressure

Hey guys ive got a major issue with my car right now I have recently been expeirencing some hard starting. I actually have to give the car throttle in order for it to start. Usually it will start and then run fine then as soon as I turn it off and go sto start it again same thing I have to feather the gas too get it going then it runs fine. Today was a different story though it started hard then wouldent stay running I noticed alot of white smoke from the tailpipes, it also looks like there is some gas or something dripping out of the exhaust pipes. I tried to start it 3 different times and each time I would blow off a different gas line, I actually think they might be vaccum lines but when they blow they blow straight gas. The firs one blew off of the fuel pressure regulator the second off of one of the lines on the emissions equip. under the intake tube that connects the throttle body to the MAF the only thing I have done differently to the car is put different gas in it I usually run 93 octane Sunoco gas I have never run anything but Sunoco the other day i filled up with 93 octane qwik fill gas the car has run like garbage ever since I am at a 1/4 tank now.
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Old Jul 12, 2007 | 04:43 PM
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Sounds like you have leaky injectors for one. Have you checked the fuel pressure?

I would also check the oil for signs of water/coolant.
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Old Jul 12, 2007 | 05:29 PM
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Sounds like a split diafragum in your FPR.

Pull the vacuum line of the FPR and if fuel is present, this is your problem.

Reasonably priced and easy to replace.

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Old Jul 12, 2007 | 05:32 PM
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Originally Posted by JrRifleCoach
Sounds like a split diafragum in your FPR.

Pull the vacuum line of the FPR and if fuel is present, this is your problem.

Reasonably priced and easy to replace.

this is exactly what is happening so do I just replace the fuel pressure regulator
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Old Jul 12, 2007 | 08:19 PM
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I orderd a new diaphram kit if anyone has any instructions or pictures of an installation please let me know Thanks, Ray
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Old Jul 13, 2007 | 08:56 AM
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Be sure to have the correct security torx bit to remove cover from regulator. Don't recall what size it is, but i'm sure someone will.
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Old Jul 13, 2007 | 01:03 PM
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Originally Posted by black panther
this is exactly what is happening so do I just replace the fuel pressure regulator
I replaced the factory FPR with a BBK adjustable unit. I hear that the Holley part is better. You may want to pull the plenum off to gain access to all the screws. Once installed, check the FP with a guage mounted on the fuel rail. Mine is set at 43 psi with the vacuum line removed. THis matches the ECM tables as configured by PCMforless.

Good Luck

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