Loses fuel pressure when warm
Thread Starter
3rd Gear
Joined: Mar 2018
Posts: 3
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From: Lubbock TX
Loses fuel pressure when warm
When my 2001 C-5 Corvette is cold, it starts just right. After driving for at least 30 minutes and stop for 5 minutes or more the engine won't start untill I cycle the key 1-2 times to restore fuel pressure. Always runs good, never quits or loses power. I talked to a local Corvette guy and he said to replace the fuel pump. I have replaced the fuel pump, with a GM fuel pump. I replaced the fuel filter with a GM fuel filter. Still does the same thing.
It acts like a fuel pressure regulator, which this car does not have. It is losing fuel pressure, but I don't know where or how. I spoke with the service manager at the local Chevrolet dealership and he had no ideas.
Could the fuel rail have an issue or could the injectors be causing the issue? It does not act like the fuel is leaking down into the engine because when the key is cycled, it starts just like it does when cold.
It acts like a fuel pressure regulator, which this car does not have. It is losing fuel pressure, but I don't know where or how. I spoke with the service manager at the local Chevrolet dealership and he had no ideas.
Could the fuel rail have an issue or could the injectors be causing the issue? It does not act like the fuel is leaking down into the engine because when the key is cycled, it starts just like it does when cold.
Thread Starter
3rd Gear
Joined: Mar 2018
Posts: 3
Likes: 0
From: Lubbock TX
Today I put a pressure gauge on and it goes to 50 when start. I shut it off and the pressure dropped 5 lbs in 2 minutes till it got to 30. It lost pressure slower after that. After 2-3 hours the pressure has dropped to 0. I'm going to drive it some more tomorrow with the pressure gauge on it so I came get some more readings.
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the fuel pressure regulator is built into the filter but if you replaced it already then you can probably rule that out
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Joined: Sep 2013
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From: Cape Coral, Florida
Hello my friend !!
Sorry to hear about your fuel pump issues. Well, the first question I’d ask is did you perform a voltage drop check on the fuel pump circuit... I would go there first... I see a lot of people firing the “parts cannon” on this forum but forget to do their “power and ground” checks first...as far as your fuel pressure it’s 55-62 KOEO and a pressure drop of LESS than 5 psi after 1 minute of key off... it could be the fuel pump check valve also !!
Sorry to hear about your fuel pump issues. Well, the first question I’d ask is did you perform a voltage drop check on the fuel pump circuit... I would go there first... I see a lot of people firing the “parts cannon” on this forum but forget to do their “power and ground” checks first...as far as your fuel pressure it’s 55-62 KOEO and a pressure drop of LESS than 5 psi after 1 minute of key off... it could be the fuel pump check valve also !!
Last edited by C5 Diag; Jun 12, 2018 at 10:59 PM.
Thread Starter
3rd Gear
Joined: Mar 2018
Posts: 3
Likes: 0
From: Lubbock TX
I have had this problem for a while. I replaced the fuel pump with an aftermarket pump, then I replaced the fuel pump with a Delco fuel pump and installed a GM fuel filter. The same problem with 3 fuel pumps.
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
Without at least doing a voltage drop on the power and ground circuit EVERY fuel pump you install will fail...if the voltage drop check is good the pump isn’t your problem. Look elsewhere !!
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Drifting
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The car is an 89. It has a three prong connector that sits on the tank very accessible. So what am I doing. Running the car with the volt meter on and seeing if it maintains steady voltage? I am guessing it should stay at 12 volts, correct?
Thank you
Thank you
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
Your car is an 89 so you should post this is the C4 Tech section !!…someone over there can help…let them know as much info about your car and your concern !!
Last edited by C5 Diag; Aug 13, 2021 at 05:05 PM.