90 f-150 fuel problem

[rob]

90 f-150 , 2 hi pressure pumps in tanks, no helper on frame, pumping from front 2 rear tank while running , truck running very rough ,20 psi fuel pressure replaced pressure regulator, front pump, pump relay, eec relay , filter , cap button ,wires, plugs ect , any ideas , other than 5 gals of gas and a match ? again ANY HELP WELCOMED tx rob

 

[rob]

by the way this is a 4.9 300 6cyl

 

[Boston_Bob]

Hi Rob ..I had a similar problem ..pumping from rear tank to front ...did a little research and found ford had a recall ..mine is a 93 f150 ..I brought it to a dealer and they fixed it for free ..some sort of valve I think ...but it ran much better after the fix ....I'm just taking a shot here ..wont hurt to check it out Good luck
Bob

 

[kier45]

I have an 88 f-350. Same problem. Low pressure pump in tank, high pressure on frame. Checked at switch power sending to rear, but no fuel to engine. When switched to rear, it pulls from front tank. when switched to front, it sends fuel to rear tank and engine.

 

[rob]

I have an 88 f-350. Same problem. Low pressure pump in tank, high pressure on frame. Checked at switch power sending to rear, but no fuel to engine. When switched to rear, it pulls from front tank. when switched to front, it sends fuel to rear tank and engine.

i found out that one of my pump diaphrams were bad i switched it out then the other went bad , so i just spliced the lines together and use 1 tank now good luck

 

[Sawman]

Ihave a 90 model f-150 with 4.9, mine was pumping gas from rear tank to engine & to the front tank. I took the front tank out & spliced the fuel lines together. No more problem, truck runs fine.