Ok, so I'm trying to figure out where my fuel pump relay is. I'm told there is more than one, one in the power distribution box under the hood by the airbox, and another one somewhere else. The one in the distribution box looks like this. More Information for AIRTEX / WELLS 1R1061 I already tried swapping that relay with the horn relay, but it didnt work. Whats happening is the fuel pump is coming on and staying without the key in run position, ya know, when you stick the key in before starting the engine and the all the lights on the dash come on, the buzzer comes on, and the fuel pump cycles on? Well, mine stays on.
Ok, so I just remembered something. If you pull the battery cable and let it sit for a while, then hook the battery back up, it works fine. Fires right up. But that only lasts a few starts, then it starts doing it again. I should mention that I did use the search function for the location of the relays, but no searches I performed helped. The ones that could describe it, the picture links were broken. Also, I tried looking in my Haynes manual and it was no help. Googling this isnt much help either. This truck has been nonfunctional for months, my other one is broken down too, I need this thing to run!
Drivers side fender near the fusible links for the ecu. There is a box for the eec connector, trailer relay, fuel pump relay. I'm in the process of checking mine as i find it odd that my fuel pump would just die out of no where.
*edit* you have the newer style i would guess that it is in the fuse box, in the engine compartment with a bunch of fuses and relays. The wiring for the 92 and newer is quite a bit different than the 80-91.
I had already swapped the large relay second from the bottom right. Maybe I should just replace them all. Thanks for the picture! It was helpful. I'm thinking the relay that the auto parts store sold me and is listed online just isnt on this truck. I cant imagine there being 4 relays total, 3 of them in that box, and 1 somewhere else randomly.
There is only one relay for a 1992 F-series truck and it is the one you changed.
Did the pumps quit when you pulled the relay out?
If they did not then you have a short between two wires someplace.
This would have nothing to do with your PCM Computer as it can not turn the pumps on without the fuel pump relay. Also the fuel pump relay must get power to its coil to close from the Power relay and the power relay will not close without power from the ignition switch.
Yes, the pump would not work with the relay pulled. Hrm... checking wiring is not a strong point of mine. I have no idea of where to start. I find it odd that pulling the battery cable and putting it back on fixes the problem though. Does that give any clue as to what the problem might be?
Sounds like you have a big load on the fuel pump circuit that is sticking (welding) the fuel pump relay closed. May be you have a bad fuel pump that is drawing to much amps. what size fuse is in the fuel pump supply circuit place in the engine compartment fuel/relay box?
It is a 20 amp fuse, as pictured. While I was out there I cycled the key on again, and it stuck on. I turned off the ignition swapped tanks, cycled the key on again, and it was gone... I cycled the ignition with different tanks several times and it wouldnt stick again. But, Ive done this before, last time, switching tanks wouldnt fix the problem no matter how many times I did it. This truck is so random with this problem, something is definitely sticking.
EDIT: Ok, so I went out and tested the fuel pump supply fuse to see how many amps I was pulling. The front tank was pulling 16.0 amps and the rear tank was pulling 16.5. These were readings while the truck was running. Are these normal readings? I could not replicate the fuel pump sticking through over 3 dozen cycles of the key. I also tried running the truck for a few minutes a few times inbetween cycles. So, until I can replicate the fuel pump sticking on again so I can test the amperage draw, I'm stuck. Any ideas? I know this truck will probably do this while I'm towing a trailer 50 miles from home and I won't be so lucky.
Do what i did pull out the old multimeter and start testing. I tested before the rollover valve (which can go bad itself) and found out the relay went bad when it activated i was only getting .35 volts.
The roll over valve is a non electric valve that is located on the top of the fuel tank and has nothing to do with the running of the fuel pumps. It is part of the Evaporative Emission System (EVAP System).