i have a 91 e150 van with a 5.SLOW efi engine. has 2 fuel tanks and 3 pumps. truck will not start. have very low to no fuel volume at fuel rail. to get anything at the schrader valve have to turn key on and off a few times. just changed fuel filter to see if that was it (has not been changed since i`ve owned it) now i`am looking at fuel pump problems. truck does not have tank select valve like a truck. it just switches what tank pump gets power (electric) all pumps are getting power and run. how much pressure and volume should the low pressure pumps in the tanks have? then how much vol and press should the hi pressure pump on frame rail have? ( have chiltons and haynes manuals but dont give enough info). can i put 12 volts to fuel pump wire at diag link conn under hood? will that turn the pumps on and keep them running contineous? will it power on the frame pump and one of the tank pumps (depending where the selector is) or does it just turn on the frame pump. what would be the best way to test lines for blockage. van is old and rusty. i know the tank straps are going to brake when i try to remove them. i also know the fuel pickup lock ring and probley fuel pickup lines will be rusty. so unless i can get some spec`s this job is going to be expensive. fuel pickups are 100 each tank pumps ar 60 each frame pump is 125 fuel tanks (because of rusty lock ring) are around 140 each and aftermarket straps are 30 each (4 required) good thing the newer vans have one pump and one tank. someone should have slaped whoever came up with the duel tank design. ford should drug test designers. all brake and fuel system lines should be stainless steel . not garbage metal or plastic. i bet it would cost the same if you figured it all out. anyhow any info would be sweet. hope it is frame pump ( i`am not that lucky) thanks for reading

 

The low pressure pumps are around 10psi. The Frame mounted pump should have anout 42lbs with the engine off or no vacuum to the regulator with the engine running.

I usually remove the fuel pump relay and jump the two large terminals with a jumper wire. This should power the frame pump and whichever tank you have turned on.