My 1991 f150 failed to start the other day. It just cranks and cranks... It's not getting any fuel and I think the problem is the switch thingy that switchs between the two tanks. I never switch it over cause the rear tanks leaks. Anyway, anyone know what it is called and where it is located? On my dads 1989 f250 the tank switch thingy was on the frame rail under the drivers door. I can't seem to locate mine. Any idea's?

 

Ford eliminated the frame-mounted dual tank selector valve in 1990, that was on earlier dual-tank models. I assume yours is like mine ('95 F-150) in which the fuel check valve is within each of the in-tank fuel pumps (what Ford calls Fuel Delivery Modules or FDM). The switch on the dash energizes one or the other of those fuel pumps and the check valve in the non-functional pump prevents filling of that tank by the operating pump.

If you have no fuel supply, my guess is (for what it's worth - I'm no professional technician) its most likely a bad fuel pump, or damaged wiring between the switch & the fuel pumps. Also, are you sure your Inertial Fuel Cutoff Switch has not been activated? It is behind the passenger side kick panel & it will kill power to both fuel pumps when an impact to the vehicle dislodges a small steel ball that rolls up & trips the circuit switch to the pumps. When that happens, the IFS must be manually reset before the fuel pumps will operate again. There is a small button on the top of the IFS that pops up, and must be pushed back down to reset it.

Also, there's a 20-amp fuse in the engine compartment fuse box that serves the fuel pump relay. Might check that. Position "O". 7th fuse slot down from the top on the right bank of fuses.

 

could also be a leak in the line somwhere (any drops on ground?), or the line is clogged up somewhere.

 

Start with basics.
When you first turn the ignition key to "on" can you hear the pump run?
If so there is no electrical problem. If you don't hear it run, switch your selector switch to the rear tank position and turn the key to "on." If you hear the pump running then the problem is with the FDM in the front tank or the wiring which connects it. If you don't hear it run on the rear tank setting either then there is an upstream electrical problem. It could be the fuse, the fuel pump relay, the inertial shutoff or the tank selector switch or any of the wiring which connects them. Get a wiring diagram or a Ford EVTM and a multi-meter and trace the circuit. When you find a place that has 0 voltage, the problem is between that spot and tha last place that showed 12v.

 

I highly recommend this modification before you do anything else. Whether it fixes your current problem or not, it's necessary on all pre-'92 EFIs. I just had to do it yesterday on an '88 to fix a no-start AND a battery drain.

 

I checked the red fuel shut off switch under the dash and it is in the down position. I'm aware of the relays under the hood, but not the fuse that was mentioned. I'm going to go check that now. The rear tank has been disconnected now for 5-6 years. I hear NO fuel pump when the key is in the "on" position. I'm guessing either fuel pump or fuse/relays.... I'll post an update tonight...

 

You will not hear the fuel pump just because the ignition is on; you will only hear it for a couple of seconds immediately after you turn the ignition switch from off to on.

 

Fixed it! The wiring harness on the top of the fuel tank and all bunged up. I cleaned the plug and verified all wires were in good shape. Smothered some dialectric grease on the pins and voila! She fired right up. Thanks for all your help guys.

 

i have a 92 f150 when i turn my key on i hear a click no sound from fuel pump she turns over gettin no fuel my back tank had leak i fixed that when i started havin trouble with front i thought it was my pump in front but now my back isnt kickin in im checkin relays any other ideas for my girl she is broken

 

Wait what? Periods help us understand.

Anyway, you are saying neither of the pumps run?

Adrianspeeder

 

I have the same problem as gypsie f150. I turn the ignition to the "on" position and I hear a click but no humming of the pump. Neither tank works as I have tried toggling the tank selector. I also have pulled off the filter and tried turning the key to "on" and have no fuel coming from the lines, no humming of the pump, just a click as I cycle the key. I hadnt been using the rear tank as it leaks, but mistakenly put fuel in there this morning so I had it switched to the back for a day or till I used the fuel up. I was thinking maybe I had sucked up some crap from that tank and yhe pump was plugged but thst doesnt explain why I get no fuel from either pump when I cycle the tank selector to either tanks. HELP!!!

 

Did you trip the inertia switch?



Read the other captions in that album.

 

Yes, I checked the inertia switch and it is depressed. I pulled the switch out and depressed it again to be sure it was reset. I have power leaving the fuel pump relay but no power at the pump.

 

So check at the inertia switch. Its connector terminals can burn, and so can its contacts inside.

 

My truck is doing that. It was running completely fine. Went to switch tanks (both work) and when i did the truck died, after i rolled to a stop I cranked it over for maybe 2 minutes and then suddenly the battery was dead (its 2 months old) After about 10 minutes of sitting the battery had power again, it cranked a few times and then died again. It keeps repeating the same cycle. Idk what would cause this to happen. Truck did this one other time about a month ago accept it started right up after sitting for a while. This time its dead and when i try jumping it, it just cranks over, never starts. Not getting fuel to the engine. Any help is greatly appreciated.