i bought a 1990 f150 about 4 weeks ago. 103,000 miles on it. starts up on a couple of cranks of the starter. sfter 600 miles i stoped at a light and it died, switched tanks and it ran great. but i noticed when i switch from the rear to the front the front tank guage was pegged. front tank was on full but not that full when i bought truck. figured it was the old fuel transfer problem. ok then ill just run on the front tank, noticed that it started right up on the front tank, better than on the rear.then after another 600 mileson the front it died. ran a pressure test and the front tank pressure drops off pretty quick, the back stays up there. from what i understand the front shuttle valve in the pump is bad and that letsgas from the back go into the front. im going to have to replace the front tank pump. assembly anyway, but what gets me is why does the engine start right up on the bad unit and not the good one. i have a 1990 with the high pressure pumps intank, no rail mounted pump. i changed the filter and made no difference. i can also hear each pump running. could the return check valve in the pump mech. affect the pumps output. thanks in advance.

 

i believe there was a recall for that problem, have a dealer run your vin and see if it was ever done, if not you could get it fixed for free!

-Jon

 

your too late to get it fixed for free , but you can buy the two check valves that go in line on the pressure lines.

 

ive heard about these check valves dave. but ive also heard that the pump has a check valve in it. guess if the valve in the pump fails you can mount an external one. do you know where id be able to buy these check valves.