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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6574
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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1999 Ford F150: a 4.6L V8 Triton..sits..fuel pump

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I have a 1999 Ford F150 with a 4.6L V8 Triton that losses fuel rail pressure when it sits for any amount of time, like over night. Is there a fuel regulator or could this be the fuel pump ?


The fuel pump has an internal check valve built into the pump to keep the fuel pressure in the fuel lines up to the fuel injectors. You will have to replace the fuel pump assembly to repair this problem. The check valve is not a separate item. It will not cause any damage to the vehicle or the engine if you do not repair it right away. Just cycle the ignition key on and of a couple of times and fuel will flow to the engine, then you should be able to start the truck.

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Customer: replied 7 years ago.
YEA! I win the bet as it now looks like my husband has to roll the '79 Ranchero out of the garage to make room to change that fuel pump! He was hoping that it was simpler than that, lol, such optimism. He's been cycling the key and just wanted to make sure he won't be doing more damage over time until he can get to this situation (the mechanics' vehicles are always last to be worked on). You have a nice one.
Your very welcome. I'd rather be driving the Ranchero myself. You don't see many of the old 1979 's around anymore.