Replaced my front fuel tank this week due to rust/leaks. Now I can't get the darn thing started.

I took off the fuel line that goes into the fuel filter and it is pumping fuel but the fuel seems to be running back into the tank when the pump is off.

Is there a check valve somewhere that should be keeping the fuel from flowing back into the tank?


Truck is a '88 F250 7.3L IDI

 

Does it run on the back tank? still have the lift pump on eng or have you gone electric?

 

It also might be the return lines, they could be letting air into them and fuel draining back into the tank.

 

Doesn't run off the back tank.

I made sure the filter was full before I started cranking after replacing the tank. I decided to check again and it was about half full. Filled and replaced . It started!!! Took about 10-15 seconds of cranking Ran for almost a minute and the died. Checked the fuel filter and it was half full. Obviously it's pulling fuel from the filter but the pump isn't able to deliver what she needs.

Was thinking maybe a pinched fuel line might be starving the pump so I checked the lines above the tank and they seem to be ok?

I'm using the mechanical pump and have been reading about what a nightmare they are to replace. Hoping that's not the problem.

 

I think maybe it sucking air you may have a bad conection at the tank were the fuel line conects to the pick up or you have done wat I did and that was hook the suction up to the return

 

Turned out to be a bad fuel pump.
Based on comments on the forum I'm replacing it with an electric pump mounted close to the tanks.
Thanks for the help!