I have had a 94 f150 2wd 4.9l for about four years now, which was in really rough shape when I got it. Around christmas I began using it as a daily driver, at which point the brakes, front end, engine, and rear springs all got some major work. Of course when I started using it alot, alot of issues started surfacing that I didn't know existed. One such issue is the front tank leaking when it is full, due to rust. I had the front tank, fuel pump, and fuel gauge sensor replaced all at the same time, and soon after, the front pump stopped working. The pump makes noise when the key is on (typical fuel pump whine noise) but the truck won't run on the front tank. The fuel pump was replaced again, and now the same problem is happening, and i'm stumped.
Does anyone have any idea why a brand new pump would fail like that? More importantly, does anyone know how I should proceed?
Any info as to the workings of the fuel system would be greatly appreciated!
Is there a relay that may have gone bad? what kind of wiring exists (relays, circuit board etc) between the selecting switch on my dash and the fuel pump?
I would run a fuel pressure test to make sure a faulty fuel pump is your issue. remember that the filter is in series with both tanks so if its a lack of fuel issue with both tanks then most likely its a filter.
i should clarify that the rear tank has perfect function. Since replacing the front pump (2 times) the pump works for a brief period of time and then fails. It makes a noise when the key is turned but the truck won't run.