Rapid Fuel Pressure Loss
03-08-2009, 05:10 PM
#1
Staging Lane
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Rapid Fuel Pressure Loss Well initially I had 40psi with key on and it would rapidly drop to zero after the fuel pump shut off. At idle it would stay at 40psi. I replaced the sending unit and instead of 40 I got 10psi. I then replaced the fuel pump with a Racetronix and I now have 50psi at idle but it still drops to zero at turn key after the pump cuts off. I have used two fuel pressure regulators (both used, but one I know worked before). I have changed the fuel filter and I have no gas leaking out anywhere. What is my next step? What should I look for? At idle I hear lots of gas getting dumped back into the fuel tank, which makes me think maybe it is the fuel pressure regulator.
Just a side note. I have cut out the door for easy access.
Just a side note. I have cut out the door for easy access.
03-09-2009, 08:22 AM
#2
On The Tree
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Almost all after market adjustable fuel pressure regulators are designed to hold pressure once the pump is shut off. The OEM system holds pressure because of EPA mandating for polution control (shorter cranking). What brand of regulators do you have?
03-09-2009, 06:10 PM
#4
Staging Lane
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The FPR I have is the factory one from a 98 and a 99. The entire fuel sending unit is brand new short of the FPR. All lines were not stiff or cracked.
03-10-2009, 12:06 AM
#7
Sounds like you have a bad regulator or your pressure gauge is out to lunch.
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03-10-2009, 08:21 PM
#8
Staging Lane
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My guess is the FPR. I've used two different ones and I get the same psi which is a little wierd. The gauge is definitely fine and I know there is a problem because of the pressure loss after the pump turns off after key on.
12-19-2012, 01:11 PM
#9
Staging Lane
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Guess I should have put a conclusion in here for future use. It turns out the o-ring around the FPR was missing. Not sure why got the fuel assembly with the rolling chassis.
