Fuel pump/No ground

[blackeye102]

Hey everybody!

I have 05 explorer with 4.0

No ground at at fuel pump

constant power at pump when key on

IM told the PCM controls the fuel pump ground is this true?

Already checked inertia switch..Its not that!

truck not starting, pump not buzzing at all in key on mode

Ill take any advice I can get thanks!

 

[FordFool2]

The Fuel Pump Driver Module (FPDM) is controlled by the PCM to pulse the ground of the fuel pump to change it's duty cycle. The pump does not run under a constant 12 VDC hot to ground. The ground side is pulsed several times per second in order to deliver an optimum fuel rail pressure. I had a no fuel situation in the past. I checked the inertia switch, fuses, differential fuel pressure sensor, etc. The answer was in the FPDM where I did not have continuity between the wire going down into the tank to the pump motor and the wire coming back.

Ended up draining, dropping the tank and replacing the pump unit. Took me the good part of a Saturday.

See link below:

http://www.explorerforum.com/forums/showthread.php?t=403643&highlight=fpdm

 

[blackeye102]

Thanks for the input!

Im gonna check the FPCM today. I got an all data sheet that gives you a break down on how to test it and bypass it, so well see. I hope its that because I hate trying to find bad grounds and wire shorts! I actually cut an access hole to the pump so I don't have to drop the tank, IT was much easier than I thought it was gonna be to do. there is even a rubber grommet ford put in, that lets you eyeball the top of the fuel pump,So I just started my cuts from there. The sheet metal is much much thinner than i thought it would be!
Have you had any problems since you changed that wire?
OK thanks again...I will post my results..

 

[FordFool2]

I didn't change a wire, I changed out the pump assembly. The test I described in the linked post proved there was an open and it was in the fuel pump motor. Good luck.

 

[blackeye102]

sorry I must have read your post way too fast!

Bench tested the fuel pump and it works well!

Tested FPDM with all data sheet today and that works fine!

Is it possible that the pump bench tests ok but still needs to be changed?
Dam this is driving me insane!...and I cant afford this silly rental any longer!

Still taking any advice anybody wants to share!
Thanks

 

[FordFool2]

Intermittent problems are some of the hardest things to solve.

Our 2004 Explorer fuel pump simply died. It was a couple blocks away, we towed it back home, and I eventually figured it our after changing the differential fuel pressure sensor first. Then I got the right rear quarter panel removed and could ring out and test at the FPDM. I really didn't do much testing of the old pump once I pulled it out.

Our 2013 Explorer died once or twice then died at the grocery store a couple miles away. It was under warranty and towed back to the dealer. It's problem was the harness connector at the fuel pump was not fully inserted and latched.

Now that you have pulled your pump assembly the conditions are disturbed. The wires going down to the motor on the pump assembly have been moved, the connector pulled, and the pump agitated. The brushes may be worn down or you may have a dirty spot on the commutator. If so, the problem may come back sometime down the road when it is the least desired. If you have >100K on the truck it may be good piece of mind to change out the pump. It is the workhorse of the fuel delivery system.

 

[blackeye102]

yes your right! I plan on changing the pump now that its out anyway, however I have read a hand full of posts on here of guys changing there pumps and then having the same exact symptoms and problems come back just a few weeks or even days later. So I would like to pin point the exact issue first. But yea at 140,000 I gotta change it any way, thats why I did not mind so much cutting the access panel. because im certain I would have to get back in there at some point. The goal for this explorer is to get 200,000 out of it... but my faith after this issue is starting to waver.
I really appreciate all your advice, Im starting to give up a little, but we need this truck to last! I been thinking about what you said about the brushes inside the motor and im wondering if maybe the bench test only worked because it sent a solid 12 volts to the pump direct and quickly, and that's why it shows to work on the bench?
Anyway im going to see my old boss tomorrow morning and see what "All Data" says to do next.

 

[howster01]

So the pump is in the tank? So where is this access panel located that can be drilled out so as not to have to drop the tank? If I do drop the tank doesn't need to be completely removed or just far enough to get the pump out? Thanks for all of your help.

 

[howster01]

Hi to all. Is this access panel you mention something noticeable when I lift the rear seats? I assume it would be on the driver's side, but is it aft or fore of the tank? I need to get moving on this so any assistance with position of this access panel would be totally awesome and many times appreciated.

Cheers,

Howie

 

[howster01]

So does anyone have a wiring diagram of the fuel pump for a 2002 Explorer Sport? Does anyone just know the wire codes for those wires? Should only be two of them. Thanks to anyone.

Cheers

 

[zdoll88]

Thanks for the input!

Im gonna check the FPCM today. I got an all data sheet that gives you a break down on how to test it and bypass it, so well see. I hope its that because I hate trying to find bad grounds and wire shorts! I actually cut an access hole to the pump so I don't have to drop the tank, IT was much easier than I thought it was gonna be to do. there is even a rubber grommet ford put in, that lets you eyeball the top of the fuel pump,So I just started my cuts from there. The sheet metal is much much thinner than i thought it would be!
Have you had any problems since you changed that wire?
OK thanks again...I will post my results..

Would you be able to send me the location you found them rubber grommets to cut the port