I have a 96 f150 4.9 5speed and I think one of the fuel pumps is bad. When I try to start it I have to sit and try to start it for 10 minutes while I cycle it with my foot on the gas. It trys to start but then it will just die. I hear the fuel pump when the key is on. It is almost like I am priming the engine. And I don't know if this matters but gas leaks from my front tank to the back tank too.

 

Is it a loud sound from the pump? Or a fairly quiet noise.

 

It is a quiet humming noise

 

Try changing the fuel filter. The pump seems fine. When they go out they generally will make a loud noise. As for the cross feeding. I don't know what could cause that.

 

Fuel going to the rear tank from the front is because the check valve in the rear pump is bad.

I would change the filter, check the regulator and run a pressure check on the system.

Also the pumps should only run a few seconds when you first turn on the key. If they are not cutting off you might want to check the pump relay.

 

Like stated above by Hawk...it's not leaking into your rear tank...it's being pumped ...

 

Ok thanks. I tried to test the fuel pressure last weekend but O'riley gave me a crappy tester and the Ford adapter was broken. So now I am waiting for my friend to get a Snap On fuel pressure tester from his shop. And i tried to change the fuel filter a couple of months ago when my truck started shaking everytime i start when the engine was warmed up but it was rusted in there.