Fueling & Injection Fuel Pumps | Injectors | Rails | Regulators | Tanks

fuel pressure issues

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Old Jul 27, 2009 | 02:12 PM
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svshawk03's Avatar
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Default fuel pressure issues

Ok I bought my 98 camaro z28 used with 40,000 miles on it. This car is a freaking lemon. I have replaced the fuel pump 4 times with stock gm parts from the dealer. I put in a new pump and i have good fuel pressure at 55 psi for 4 to 5 days and the car starts up fine. then after that when I turn the car to the on position the fuel pressure goes up to 55 psi then immediately drops to zero with in a few seconds. I have swapped out all the relays. What I want to know is what is causing that?
and is there a vacuum line that connects to the fuel pressure regulator in the tank? If so that is missing and could be my problem...
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Old Jul 27, 2009 | 08:27 PM
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If the pressure falls to zero, you have one of these problems.

1. An external leak, which you would see....
2. An internal leak, which would not be duplicated with 4 new GM pumps as they are fully assembled.
3. A bad regulator, which comes with a GM pump so you should have had a few different ones in there already.
4. A leaking injector, which you should check.

Not sure why it is good for a few days????
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