ok i hookewd up a fuel pressure guage to see if i was getting the right amount of fuel at high boost sine i was hearing knock lately. i take it for a ride and with 42.5lb. inj. and a testa chip i had idle FP set at 39. i would see the boost go up to about 20psi but the FP would go to about 50 and bounce around and go no higher. i decided to put my stock 237 FPR on and with the idel FP at 44psi the fuel would go up to about 55psi with 20 psi of boost. not sure what it is so i go and pruchase another fuel pressure guage thinking that one was bad sine the car pulls just knock a little at high boost. the pressure also seems to bounce around a little when im on it about 1psi i install the new guage and go for a blast with teh FP at idle at 39psi adn about 18psi of boost. the guage goes up to about 43 but pulls. i dont think its the guage all that much. its a new fuel filter. how do i check out to see if the fuel pump is pumping enough, how do i know if the FPR is working??? i have a Reds XP plus pump and billet FPR that are about 8 months old. any idea on m,y werid reading?
possible fuel pressure probs??
- Thread starter 1985GN
- Start date
John Larkin
Sublime Master of Turbology
- Joined
- May 25, 2001
I don't know if the pump itself is bad but maybe one of the connections in between could be. It goes up basically 10 lbs regardless of the regulator from what you wrote. Could be it starts bleeding off pressure once it reaches the limit of the weakest link in the system. I'd guess it's in the tank but it's a long way to the rail so it could be anywhere in the system. There is a rubber hose fuel line splice near the driver fenderwell that has been known to collapse on some cars. Might start there, considering it's 17 years old.
Carolinaturbot6
Pride. Freedom. America
- Joined
- May 24, 2001
You can check the pumping capability by:
1) Disconnecting the schrader valve at the fuel rail.
2) Hook a rubber hose to the rail there.
3) Apply 12volts to the fuel pump test lead (black wire/connector behind the alternator).
With 12volts applied to the test lead, you should get about a gallon of fuel in 60 seconds. Of course you want to have the other end of the hose in a catch can of some sort.
1) Disconnecting the schrader valve at the fuel rail.
2) Hook a rubber hose to the rail there.
3) Apply 12volts to the fuel pump test lead (black wire/connector behind the alternator).
With 12volts applied to the test lead, you should get about a gallon of fuel in 60 seconds. Of course you want to have the other end of the hose in a catch can of some sort.
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