icu1954

i have been having problems with my 91 ford f150 5.8 not starting because fuel pump refuse to prime sometime,i have another post about that on this site.I directly ran 12 volts to fuel pump relay plug without the relay and nothing,not a hum.This is a brand new fuel pump. I might go out side tommorow and fuel pump may run for a few seconds and then no more.Could somebody give me an insight on this?

Eric Fullerton

Have you considered that the new fuel pump may be defective?

icu1954

thinking about going back to the fuel pump pigtail close to the tank and run test wire straight to the battery and see if fuel pump runs.then i'll know it is in the wiring.

Chris_1

iTrader: (1)

If the new pump cost less than 150.00, I would suspect it.

techrep

iTrader: (1)

What was the original problem that made you change the fuel pump ?

icu1954

no start sometimes,fuel pump works some time ,sometime not,cuts off, no fuel pump hum,come back later,fuel pump hum and it starts.

techrep

iTrader: (1)

So same problem now..

icu1954

yes same ol problem.

techrep

iTrader: (1)

So.. probably not the pump. Have you troubleshot the wiring ?

icu1954

yes as best as i could,i have power to my fuel pump relay plug,also power to my fuel cut off switch,and both fuel and ecm relays are clicking on and off with the switch.inertia switch has power to green and yellow wire when switch is on.Also i jumpered inertia switch and no sound of fuel pump.