Fuel pressure question
Thread Starter
Intermediate
Joined: Oct 2001
Posts: 36
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From: rose hill ks.
Fuel pressure question
My car is acting like it's flooded and dies if I try to accelerate. I bought a pressure guage and tested it. It shows no pressure. I think I'm doing it right. I hooked it up to the schrader valve and turn the key on. I here the fuel pump run for a few seconds and it still shows no pressure. What do you think? Fuel filter? The thing that has me puzzled is with no pressure why is it acting flooded?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Fuel pressure question (clyde)
I'll assume you checked your connection and there are no fuel leaks; further that you have to walk around the car to read the gauge after you turn on the key.
If it shows no pressure after the pump runs for 2sec but it starts and runs it sounds like a stuck injector. Of course it could be a problem with the fuel pump check valve or a hole in the fuel pressure regulator diaphram.
To check the gauge & regulator start the engine and read the pressure; it should be in the 30s with the vacuum line connected & in the 40s with it disconnected.
BTW, what year Vette?
If it shows no pressure after the pump runs for 2sec but it starts and runs it sounds like a stuck injector. Of course it could be a problem with the fuel pump check valve or a hole in the fuel pressure regulator diaphram.
To check the gauge & regulator start the engine and read the pressure; it should be in the 30s with the vacuum line connected & in the 40s with it disconnected.
BTW, what year Vette?
Thread Starter
Intermediate
Joined: Oct 2001
Posts: 36
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From: rose hill ks.
Re: Fuel pressure question (65Z01)
My car is an 85. When I started it, it still shows no pressure althoough it will only run for a feww seconds. I'm changing the filter now to eliminate that question.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Fuel pressure question (clyde)
If it runs but only for a few seconds I think you have two problems:
1) doesn't hold fuel pressure for reasons stated above
2) the oil pressure gauge is not supplying +12Vdc to the fuel pump after the engine starts.
To test for #2, jumper +12Vdc to ALDL pin "G" (lower left) and start the engine. That will supply power to the pump, bypassing the oil pressure switch. If this works replace the oil pressure switch (mine is located on the back of the intake base to the left of the dist, check for yours). If it runs also do the fuel pressure checks mentioned above.
Let me know what you find.
1) doesn't hold fuel pressure for reasons stated above
2) the oil pressure gauge is not supplying +12Vdc to the fuel pump after the engine starts.
To test for #2, jumper +12Vdc to ALDL pin "G" (lower left) and start the engine. That will supply power to the pump, bypassing the oil pressure switch. If this works replace the oil pressure switch (mine is located on the back of the intake base to the left of the dist, check for yours). If it runs also do the fuel pressure checks mentioned above.
Let me know what you find.
Thread Starter
Intermediate
Joined: Oct 2001
Posts: 36
Likes: 0
From: rose hill ks.
Re: Fuel pressure question (65Z01)
Changed fuel filter and my car started and stayed running for about 3-4 minutes, had a little hesitation when I accelerated. Fuel pressure came upto around 30-32 and I let it idle for a few minutes and the pressure began to drop down to zero and it died. I'll try your suggestions what do you think about changing the regulator and if so where is it located? Thanks for your help.
Safety Car
Joined: Jan 2002
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From: Jeffersonville Indiana
Cruise-In III Veteran
Re: Fuel pressure question (clyde)
I had fuel pressure problems on my 85. The pump was replaced and the ground wire to the pump housing was reconnected as I was losing a volt and a half to the pump. Also check the pump relay.
