fuel pressure
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Freshman User
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fuel pressure
I have a 91 ford f-150 with 302. It will start normal and run for about ten minutes then the feul pump loses pressure and it will jump around for a while and then go again but not able to reach normal rpm but the truck will idle fine. can this be the feul pump i hardly ever used the back tank and the pump is locked up on it. if it is a pump which one should i replace the front or back.
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Joined: Aug 2007
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Mines is doing the exact same thing. Manual says verfiy that the fuel reservoir (drivers side frame rail) is not plugged up. Discharge fuel pressure and disconnect the return lines exiting the reservoir, attach a hose to the return line fittings on the reservoir that go back to the tanks, and run the pumps. Each hose should fill a 16 oz can in one minute. If not, the reserviour is plugged and should be replaced.
You have three pumps, a low pressure one in each tank and a high pressure one mounted in the frame rail under your butt.
You have three pumps, a low pressure one in each tank and a high pressure one mounted in the frame rail under your butt.
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Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
You have two fuel pumps, one in each tank and none on the frame and the reservoirs are inside the tanks.
If the rear tank is bad inside then I would replace the front if the rear does not fill when you are on the front tank. If the rear fills running on the rear then you have a bad rear fuel module in the rear tank and it will have to be replaced before you can run on the front. The opposite is true if you run on the rear and the front fills you will have to replace the front before you can run on the rear.
The link given is to the wrong fuel system.
Check your fuel pressure with a gauge and if it drops off fast after you shut off the engine then you have a bad check valve in one of the two fuel modules.
If the rear tank is bad inside then I would replace the front if the rear does not fill when you are on the front tank. If the rear fills running on the rear then you have a bad rear fuel module in the rear tank and it will have to be replaced before you can run on the front. The opposite is true if you run on the rear and the front fills you will have to replace the front before you can run on the rear.
The link given is to the wrong fuel system.
Check your fuel pressure with a gauge and if it drops off fast after you shut off the engine then you have a bad check valve in one of the two fuel modules.
Last edited by subford; Aug 14, 2007 at 06:58 PM.
