Hello everyone- i hv just purchased a 1990 F150 Lariet 4 wheel drive, and when switching from back tank to front tank it dies within 5 seconds and does not even register that the tank has fuel in it (it is full), any ideas as to where to begin? I found a thread on this issue, and it main lined on the fuel pump as being the most likely problem, but since it didnt say anthing about the fuel not registering, i thought mayby it was the dash switch, thx for any help everyone!

 

It could be the switch, but most likely the fuel delivery module (FDM). The FDM has the pump & the sender on it...

 

That's in the tank(s) right? Which one? Lol

 

Sorry, wrong thread.

 

ok, i have made a quick attempt to isolate the issue, and when i turn on the ignition switch, i can hear the rear tank pump working, i then shut it off and use the dash switch to change tanks and i hear nothing at all. would the pump not working make it nor register the gas in the tank not pumping. thx

 

The pump not working wouldn't make the gage not work, but since both the pump and the sender are in the tank, my guess would be the wiring to that tank, and probably closer to the tank rather than at the switch.

 

My guess would be a bad tank.
The rusty gummed up tank has made the pump go bad and the sender not to work.
The gauge and the pump are separate items and the only thing in common is the selector switch but I dough that two sets of contacts would be good for one tank and bad for the other.

But the wiring could be ripped off the tank but you should be able to see that if that is the case.



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