fuel pressure dropping under load April 13, 2006, 11:34:21 PM ive recently upgraded to a gss307(255lph) pump and an aeromotive regulator. ive also changed the fuel filter, and by-passed the inertia switch. everytime i "get on it" the fuel pressure will drop down to about 20psi, and then come back up after fluttering the gas pedal. i have the pressure set at 40psi(vac line off) right now, and have a fuel guage mounted on my hood for monitoring purposes. the guage is hooked up via the schrader valve. this happens while on motor and on the nitrous. fuel for the nitrous is pulled from the extra port on the regulator.ive checked the voltage to the fuel pump from the relay while someone else drove the car, and the voltage never dropped. the regulator also holds pressure after the car is shut off.now, why is the pressure dropping? what would be the solution? Quote Selected
fuel pressure dropping under load Reply #1 – April 14, 2006, 12:38:32 PM Did you have the problem before the changes??? If the voltage is OK the problem just about has to be a restriction in the system(lines, filter or maybe regulator) or weak pump. There are several tests you can do. One would be connect a line directly to the output of the pump and check for volume. In 60 seconds you should get 1/60 of the 255lph rating of the pump. Also you can check pressure at the pump, dead ended the pump should create over 100lbs pressure(quick test here, DO NOT run the pump for more than 3-4 seconds at a time). Quote Selected
fuel pressure dropping under load Reply #3 – May 21, 2006, 08:36:38 PM Quote from: SLEEPER T-BIRD 87weak pump.i really dont believe it's the pump. it did the same thing with the stock one, too. it'll keep steady pressure just fine while driving "normal". im thinking the pump is cavitating due to how the pump is "clocked" in the tank. the sudden jerk the car would get when shifted hard with a T5, would run the fuel out of the baffle. remember, our tanks are much more different than the mustangs.does this sound about right?also, the lines appear to be clear of any kind of clog. i was able to blow through them with just my mouth. Quote Selected
fuel pressure dropping under load Reply #4 – May 21, 2006, 10:57:44 PM I would move the NOS fuel supply to the schraer valve and move the guage to the Regulator. The fuel drop might be from the press bleeding off from the regulator. Also with the vac line off the fuel press should raise about 6- 8 psi? Could be a bad regulator? Quote Selected
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