Hello guys,

new poster here, but I've lurked this forum for years since I have a small fleet (4) of Ford trucks.

here's my problem: 1994 F350 C&C with service body, 5.8 V8, auto.
Truck was running fine thursday, filled up with gas and drove home from job 30 miles. Backed truck into its slot in the driveway and shut it down.
Friday morning I climb in truck and turn the key. No start. (truck always starts instantly- 95k miles). I turn off the radio and listen as I switch key on again----ah ha---no initial fuel pump spin.

First thing I checked was inertia switch- not tripped.

I then checked the FP fuses in the underhood power box- fuses good.

Next I swapped the fuel pump relay with the horn relay, still no fuel pump with keyon.

Back to inertia switch, pull plug and check for 12v- no voltage present.
jump the connector with a short length of wire- nothing

Back to underhood box- 12v on 1 side of FP relay coil circuit and 12v on 1 side of relay load circuit.

Jump across FPR load circuit terminals with jumper, fully expecting FP to run- nothing, not even a spark.

Jump across the relay coil(control) circuit- still no FP, but at least now there is 12v present at inertia switch.

I'd love to check voltage at the fuel pump connector at tank, but this is a dual wheel/service body truck and it is IMPOSSIBLE to get more than an outstretched finger on the connector, to check there I will have to either drain the tank and drop it, or unbolt the body and lift it.

My questions:

what/where energizes the fuel pump for the initial spin up? (I'm assuming the ECM powers it as soon as the motor is running)

what else can I check before I have to start major dissassembly on this truck apart?

Ideas????????


TIA,

Mike Kelly
Stanley, NC

 

checking codes I get "542"
checking code definitions I get "Fuel pump circuit failure"

since it is impossible to get hands on the connector along the frame rail that powers FP, can someone please point me to a link or a diagram where I can learn what color the wires feeding fuel pump are. That way, at least, I can check for power by penetrating the harness where it runs past the transmission, before I start major dissmantle...

ANY ideas are Welcome!!!!!!!!

Thanks,

MikeK

 

so today I drained the tank and dropped it down, checked for power to the pump and was getting 12v at initial spin-up.

bit the bullet and picked up a new FP at NAPA for $175 (ouch) and that is just the pump motor, not the entire assemble w/sending unit.

nothing about this job was easy, as it had to be done in the driveway. getting tank back into position, working after dark by flashlite, cold as hell, proved to be the hardest part.

I'll pick up my tools in the morning and get this truck out to make a few bucks.

oh well, its done.