MBLUNT

I have a 94 f-150 with a dual tank set up. The front tank stop working years ago so I switched to the rear only. Truck had been running fine but all of a sudden I wasn't getting fuel to the carb.

I assumed that my rear pump was dead so I bought a new tank with the pump and assembly already in place. After getting everthing replaced I still am not getting fuel to the carb.

I opened the line at the fuel filter and it had remaining preassure ( all over my face). However I left the line open and turn the key and no fuel came out. I think I am hearing the fuel pump engage so why is the fuel not coming thru the line.

Could it be getting stop somewhere elese in line like maybe the front fuel assembly since they are connected???

87f-150

I would change the fuel filter and check the fuel pump relay. You also may have a stoped up fuel line, also check fuel pressure with gauge.

MBLUNT

I did check the relay and that seems good. I switched it with the horn relay I knew was working and that seems to be fine. As I said I hear the pump kick in. I have the line wide open before it enters the fuel filter, and nothing comes out.

I assume the line from the back tank merges with the front tank line. I'm asking if someone understands that route the fuel takes to get to the fuel filter. It seems to be blocked.

87f-150

Both tanks run to a switching valve you can take the fuel line that runs from the
Rear to the valve loose to see if you have pressure there . I would also check to see
If you have power to the swiching valve to see if its worrking properly. That valve maybe
Bad

87f-150

That valve is before the filter. The valve should be next to the transmission crossmember mounted on the driverside frame rail.

sdmartin65

The pump will only spit out a small amount with filter unhooked. Thought i could drain the tank that way, but wont work. Seems to have a shutoff if there is no back pressure

imp

"Carb" you said? I hope yer not feeding EFI pressure to a carburetor! imp

sylver91

91-96 trucks do not have a "switching valve". The lines are teed to each pump in each tank. Just because the pump in on, doesn't mean its working properly or you have some severe blockage in the lines somewhere from rust and corrosion. You need to have the fuel pressure tested with a gauge.

fordtrucknut

might as well get a new filter,
unhook the lines at each section pumps/filter/behind the engine.

use an air compressor with a blow nozzle, blow out each section of line.

your front tanks pump might have gone bad where the one way check valve it letting the fuel from the rear tank to feed directly into the front tank, but you should still get fuel from the rear coming out of the line even if it is feeding the front.