I'm a diehard Ford truck guy and love the Navigator, but it left me stranded with my daughter on the way home from visiting my mother at the hospital the other night. I had cruise set and it just lost power and stalled out. When i tried to restart it the motor turned over fine and it seemed to want to start but it would spudder up to about 1000 rpm and then spudder out. Now it won't even do that. Still turns over fine just no indication that it wants to start. Looked at some forums and checked the fuel pump fuse and that was good and then the fuel pump cut off switch inside the rear drivers quarter panel and that was fine, so i have no clue now. The engine light was on. My buddy had a code reader that said #1 and #8 were misfiring and there was a vacuum leak. The dash reads fuel cap, but I replaced it with an aftermarket one and it made no difference. I own 2 V10 Excursions and a 4.6 Expedition and seem to always have an engine light for a coil pack so didn't think twice about it. Anything that jumps out at anyone that I can check to get this thing running? First time a Ford has left me stranded.

 

I'm *guessing* that your Navigator uses a FPDM (fuel pump driver module) located on the rear cross member. They tend to corrode and at some point no longer control the fuel pump. Inadequate fuel pressure could cause your #1 and #8 misfires, as well as make the PCM think it is running lean.


I'd put a fuel pump pressure tester on there and confirm if fuel pressure is the problem.

 

Can't thank you enough. Going to check it right now and I'll post the results. Thanks again.

 

Try starting fluid to see if you can get it to run a bit. This will help confirm if it's a fuel issue or not.

 

Thanks. Tried the starting fluid yesterday and it fired up. I think pdqford hit the nail on the head with the fpdm. Heading to auto zone now to get one so I'll let you guys know, but it looks blatantly obvious to me, even as a novice, that if this isn't the problem it definitely would be in the down the road. Corroded so bad that i snapped both bolts taking it out and just touched it wit a screwdriver and a big chunk of it fell off. Definitely not a good design.

 

Thank you pdqford! I really can't thank you enough. Replaced the fpdm and she fired right up. I'm posting a YouTube of the fix crediting you as well. You definitely know your Fords my friend. Thanks again.

 

It's not so much the design, but where it's located.
With the many people having corrosion issues with the FPDM it seems worth looking at putting it in a plastic box or make an extension harness to move it inside the body.
Did replacing the FPDM fix the misfires?

 

It seemed to. No engine lights. The new fpdm came with standoffs to hold it off the frame, so they obviously realized there was a design issue. Any time you mix electricity and water (expecially salt water from winter roads you get electrolysis. At least the standoffs will prevent the water and salt from getting stuck behind it.

 

You would expect the Ford design engineers to have this basic knowledge without having to experiment with our money.

 

does an 05 Expedition 5.4L have this same module under the cross member?

 

Yep, I saved mine by installing spacers on it. Wasn't corroded yet, and hopefully won't have to deal with it.

 

common issue on 05-06



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Good Troubleshooting! Way to quickly narrow down a problem!

Does anyone know if Ford changed the location or design of the FPDM in later series Expedition/Navigators. I have a '11 Navi and would like to know if this a potential problem for me.

Thanks.

 

Yes - the new units come with spacers but do yourself a favor and give the alu body also a coating of either a clear lacker or a rubber underside spray. I just changed mine out since it had holes in it too and made sure to coat it with 3M rubber undercoat.

Glad it solved your issue!

 

I was going to do that but the unit I bought from Auto Zone was painted already. I also considered hitting it with flex seal or similar, but was concerned that it would be able to dicipate the heat.