Dual Gas Tanks (Rear quite working)

[Tyler St.Clair]

In my 94 f150 5.0 rear wheel drive my back gas tank quite working. I know it has gas in it. I am absolutely positive that it has gas because I just filled it up. But when ever I switch over the gas tank over from the front to the rear it runs for a couple seconds then it dies. But it runs when the switch is on the front tank with no issue. I can hear the pump kick on when I turn the ignition on but it sounds a little different than the front one sounds. Any ideas on what this could be? Is it my fuel pump?

 

[fatherdoug]

Could be the switching valve, fuel pump, or a plugged sock on the sending unit.

 

[Fellro]

It is a fair chance the pump is bad, but you need to do some testing to validate. Be sure it is getting power for one, but the quick check to at least see if it is running is to have someone turn the key on and listen for it to run. You should hear some kind of sound from the tank for about 30 seconds. It should come on again when the motor is cranked.

There is no switching valve on 94's, discontinued as of 91.

 

[Tyler St.Clair]

The rear pump does kick on i can hear it but when i start the truck it dies after a couple of seconds but runs on the first tank no problem when i have it switched over to the first tank.

 

[m78]

Hearing it run doesn't mean it's pumping.

 

[Fellro]

Yep, next have to verify it is pumping enough to keep it running. Pressure check is in order. These pumps are on their own, there is no secondary pump on this year.