I need help with a fuel problem. 89 E250, 460 EFI and I have no fuel pressure at the fuel rail. I pulled the fuel line at the tank side of the fuel filter, turned the ignition on and I get no fuel out of the line. The fuel pump on the frame comes on for a second or so then stops without pumping any fuel. The van has dual tanks and this happens when either tank is selected. Could this just be a bad pump, could a bad pressure regulator cause this? Can fuel pumps be pressure tested? I don't want to start replacing parts that are good. Anyone have any ideas on how to narrow this down a bit more. Thanks.

David

 

the first thing i would do is check for power at both in-tank pumps while the key is on and the specified tank is selected. at the tank, one pair of wires controls the gage, and will be obvious by your test light glowing on and off when you touch it to that wire. it should have a ground that works with it. these aren't your concern, you care about the pump wiring, which should be heavier than the gage wiring, and should have power with the key on, and a good ground on the other wire for it. I SUSPECT YOU AREN'T GETTING POWER HERE, but you need to confirm that.
if my guess is right, review a wiring diagram - i don't remember if the pump power is switched through the tank selector valve, or elsewhere, but whereever it is, check for power at that point. continue checking upstream until you find something that does have power, and go from there

on second thought, i believe this should have an "inertia switch" that is designed to shut off power to the pumps when in a wreck. i've seen these go bad before, so you might want to find it, unplug it, and short its 2 wires together for a test - or start by testing it for continuity, and check for power at it. in an 87 f-truck i worked on, it was above the driver's left foot, though the books say it exists on the right inside of the firewall for his truck.

 

The pump should only run for one second each time the key is turned on.
To keep the power on for testing unplug the high pressure pump so it will not burn up as it uses the fuel to cool itself.
The short pin #2 to pin #6 or ground pin #6 of the self-test connector and turn on the key.
Images below for the self-test connector.
Maybe.
No
The tank pumps should putout from 7-12psi going into the high pressure pump. You check the high pressure pump at the fuel rail with a gauge as you done.

The self-test connector:




Disregard the relay at the bottom as it was for replacing the stock relay with a newer stile relay. 150 and the 250 have the same fuel pump wiring also.

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Thanks subford and joshofalltrades. Now to find my continuity tester and figure out where I have current. If my inertia switch was bad would my high pressure pump come on like it does? Also, between the tanks and the high pressure pump there is that fuel reservoir/tank selector piece. Can these units get plugged and prevent fuel flow or is it just an electric switch that selects which tank to use? The fuel in the tanks was rather old ( probably a couple years) and although I treated the fuel with Stabil during the winter months the gas has a definite old smell to it. Kind of smells like paint thinner or turpentine. I am going to drain both tanks and start with fresh gas. Is it possible that old fuel can cause problems like this? Thanks again.

David

 

it sounds likely that the inertia switch isn't the problem, but it can't hurt to check.
according to the diagram there, i would check at the in-tank pump first, then the tank selector valve, then the inertia switch, then the FP relay...
on second thought, looking at that diagram again, the problem almost has to be in the tank selector valve, or in the wiring near it. the fact that your HP pump works proves that the problem is somewhere after its wire tees off from the others

 

Use a test light with a bulb in it so you put a small load on the circuit. You will get a false reading with a meter as you will get back feed from pin #8 of the EEC Computer.
The selector switch in the cab selects the tank for the fuel gauge and the fuel pump to run in that tank.
The fuel reservoir/tank selector valve on the frame switches to the tank that the in-tank pump is running. The fuel pressure (5+psi) from the tank will switch the valve to that tank.

If the high pressure pump runs and there is no fuel to it then:
The inertia switch is OK
The fuel pump relay is OK.
The fuse links coming off the starter solenoid are OK.

Your fuel system:


There will be no fuel filter in the reservoir valve on your year truck, just the one on the frame:

The fuel reservoir/tank selector valve on the frame.


The plug at the top of the fuel hanger:


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I wanted to have some information today but the weather here has been so hot and humid that I couldn't force myself outdoors to work on the van. You guys have given me some good direction and I appreciate it. I think it is going to cool down on the weekend and I will be back in business. Thanks again.

 

Ok, I decided to start dropping tanks because I think my first problem is fuel quality. The fuel inside was ridiculous and I am going to have to seriously clean this tank to try to remove the rust that is inside. I am also going to have to replace the pump (Ford Part # E9UF-9H307-BA). I have not been able to locate this pump. Does anyone know if this part # has been replaced by another? Are the aftermarket pumps any good? I would appreciate any suggestions. Thanks.

David