Starting Problem!!!!
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Joined: Jun 2008
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I just did a fuel pressure test. i hooked up the gauge and put in the jumper wire between the DLC connector and a good ground and turned on the key and with the pump constantly running i got 40psi on the gauge(but it took a few seconds to hit 40psi), when i turned off the key i lost nearly all fuel pressure in about 10 seconds and when it finally quit dropping it stopped at about 10 psi. i Did the engine running test as well and with the engine running and gauge hooked up i had 45 psi of pressure. it said in my repair manual to perform a fuel pressure regulator test but i just replaced the regulator a week ago so i dont think its that. i believe its simply a fuel pump that needs replaced. but if anyone out there has had a similiar problem i would greatly appreciate any input. thanks again for all replies.
Well the fuel pressure is within specs but the static pressure isn't. The book says it can be a faulty fuel pressure regulator, leaking fuel injectors or a stuck open fuel pump reverse check valve. I have been unable to find a separate check valve, the book seems to say it is a part of the fuel pump. Do you have dual tanks? If only one check valve is stuck the fuel pressure will drop with either pump, so you will have to test each pump.
During pressure test use vice grips to pinch shut the fuel feed line (not return) close to the tank. Do it with each tank near the tank, one at a time. If the pressure drop slows then the bad pump is in the tank you are pinching off. Pinch the line on a rubber section, not a plastic section. Also, you will need to pressurize the system, shut off the pump and clamp the line, in that order and pretty quickly since the pressure drop is so fast. You might want to rig up a remote switch to turn the pump on and off, or have a helper.
