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Dyran1
New User
Jul 21, 2010, 5:57 AM
Post #1 of 6
(1973 views)
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Fuel pressure problems
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I have a 2002 Silverado 4.3L 95000 miles thats not holding fuel pressure and I cant find why? I have replaced the filter, pump, regulator and injector 0-rings. When I first turn the key the pressure shoots up to 60psi then drops down as soon as the pump shuts off to around 25psi and holds there..it will run if I crank it around 50psi but misfires and gives the P0300 reading. So what am I missing? I thought it was a bad fuel pressure regulator to start with but that didnt solve it..I even replaced the regulator a second time.. I plugged the return line and the pressure held around 55psi and it ran fine..what else could it be? Frustrated! ugh! lol thanks guys for your help
removed links put in by other sites.
(This post was edited by Hammer Time on Jul 21, 2010, 6:06 AM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Jul 21, 2010, 6:10 AM
Post #2 of 6
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Re: Fuel pressure problems
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What your going to have to do is systematically isolate which direction it's leaking to. Do this by building pressure and pinching off lines. First, with a fuel pressure gauge installed and pressure built up, pinch off the feed line and see if the pressure holds. If it does, your problem is in the tank. If not, try the same thing with the return line. If that makes it hold pressure, then your problem is in the engine area.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Dyran1
New User
Jul 21, 2010, 8:02 AM
Post #3 of 6
(1960 views)
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Re: Fuel pressure problems
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Thanks for your reply....I have plugged the return line and the pressure held...is there any other way for the fuel to return to the tank except through the regulator?
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Hammer Time
Ultimate Carjunky
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Jul 21, 2010, 8:10 AM
Post #4 of 6
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Re: Fuel pressure problems
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If it holds pressure with the return pinched off, that proves that the check valve in the pump is good and the regulator is not holding it back as it should be. This shouldn't be causing you a lot of problems though because it should build pressure back up withing a second or two.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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ThGeneral1
Novice
Jul 22, 2010, 5:21 PM
Post #5 of 6
(1947 views)
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Re: Fuel pressure problems
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I replaced the regulator a second time it did not fix the problem..its causing major problems when my fuel pressure drops to 25psi..some have suggested I replace the spider assembly..thoughts on this?
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Hammer Time
Ultimate Carjunky
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Jul 22, 2010, 5:24 PM
Post #6 of 6
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Re: Fuel pressure problems
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Are you saying it drops while the engine is running? It should recover that in 1 to 2 seconds of cranking and start right up.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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