straton08

Hi, I have a 2004 F-150 5.4L Pickup and it broke down on me a couple days ago. I've narrowed it down to a fuel pump problem, thru checking relays and shutoff switch, etc. I've replaced the fuel pump and it's still not working. I checked the voltage and it's getting 12.4V to the pump. The truck will start, but wont take fuel and eventually shuts off. I'm lead to believe this may be a problem with either the Fuel Pump Driver Module or possibly even the Powertrain Control Module?? If anyone knows, is there any way I can check the FPDM without having to go buy one? Or does anyone have any suggestions at all, if Im perhaps way off here?

wde3477

What shape is your fuel filter in?
Unless they've changed things - the fuel pump should stay running whenever the motor is running.

Not sure what you mean by 'won't take fuel'???
Consider checking your fuel rail pressure - perhaps you have a faulty pressure regulator or somehow the injectors are simultaneously shutting off?

ktmboyz

have you looked at the driver module? if you drop the spare tire, its on the crossmember just foward of the spare and to the left of center ( looking from the rear ) There is a big problem with them building corrosion underneath between the module and where it mount on the crossmember. I have seen a couple with so much that it actually split the module in two.
I would remove the module and inspect it, to be certain thats the problem back probe the fuel pump feed at the module and check for voltage as it runs and dies, you will prob find the voltage drops off then the truck dies. Make sure you backprobe it and check it as its running not just unplugging the connector and checking voltage at the pump.

Good old Bill

Like both inputs, both filter and this driver module. If ktmboys would like to further describe the function of it, I know I would be appreciative.

ktmboyz

The fuel pump driver module controls current flow to the fuel pump on newer style returnless fuel inj systems. The pcm monitors fuel rail pressure and eng load, then inturn increases or decreases current to maintain proper fuel pressure. So what you actually are getting is a variable speed fuel pump. On you're model pressure should be koeo 35-45, koer 28-55. hope this helps

straton08

Man, I really appreciate the feedback. I've been busy and just got freed up, and Im going to follow your advice and check this stuff out. Im no mechanic by any means, but cant really afford to take it to a shop unless i have to. Thanks a lot guys. Ill be in touch to let you know what i find.

straton08

Yeah, I actually took the driver module out and just looking at the underneath, it had a small hole corroded into it. I knew it was junk, so I took the plastic cover off, breaking the brittle thing into pieces in the process, and looked at the computer board.
The casing had actually corroded against the cpu board, which i believe may have been shorting it out? The board itself didn't look too bad, so i cleaned it up and plugged back in, turned the key and "POW!", it actually started and stayed running! So, I have an idea to basically rebuild a case for it: I'm gonna use the old case and fill it with epoxy, should keep it water tight and keep it from vibrating apart, and at least use that module til i can afford another one. Hope it lasts that long! I'll let you all know if it works..thanks!

ktmboyz

Great!! now when you reinstall it get some longer bolts and space it away from the frame with some washers so there is an air gap behind it. The updated modules come with studs to put in place of the bolts then you mount the module on the studs and secure it with nuts. But longer bolts and stacked washers will give the same results

fordman1222

Hey Straton. Mine cracked in half and is hanging by the wires. I was going to try to fix it with epoxy also. What are your plans to epoxy all the broken pieces back together, or to make a new mold? Thanks.

Mod (Ret.)

Careful with the epoxy; the circuit board may overheat if you fill the gap between the cover and circuit board. I'd epoxy the holes and/or cracks, but would not fill the void (space) between the cover and circuit board.