2003 Cranks but will not fire

[CaptainKrunch]

On my 2003 I went ahead as a precaution and just bypassed the fuse panel fuel pump relay completely. Do a Google search or search for the wiring diagram to figure it out. Use a good quality relay like Bosch for this.

I believe I used the grounding signal from the pcm that goes to the original relay as a grounding signal for the bosch relay. The output obviously goes to the green\yellow wire going to the fuel pump. I got constant hot by wiring a terminal into the post of the main terminal powering the entire fuse box in the passenger side floor area.

Of course I put an inline fuse in right where I tapped the main power terminal.

I thought about putting a small led on my dash somewhere that lights up when fuel pump is getting power but who knows.

So when the key is turned on the pcm sends a ground which closes my relay and sends power back to the fuel pump using the original wiring.

 

[jpritter]

Sounds like it may be fuel pump relay problem.
https://www.expeditionforum.com/threads/power-distribution-relay-issue.26809/page-3#post-323448
Also this: Didn't state your mileage but my 2004 had this problem at 100427 miles.

Like riphip said, likely the fuel pump driver. I had the exact same issue a few years ago. Dealership had a difficult time getting it changed, the driver is made from a different metal than where it was mounted, so it was fused to the mounting point.

 

[dano]

How about this, which I haven't seen yet...a while back, my 05 Expy displayed the same symptoms. Turns out it was the fuel pump driver module. Its a computer thats mounted on the frame rail, I think in front of the left rear wheel. This is one of Fords better ideas as a place to put this where mosture and salt and what ever else junk gets up there, between the unit and the frame. It then corrodes a hole in the module and shorts it out.
My son's 06 F150 experienced the same thing, shortly after mine quit.
I found this, hope it helps...https://www.expeditionforum.com/threads/fuel-pump-driver-module.5100/

 

[riphip]

OP has 2003. No Fuel pump driver module (FPDM) until 2005

 

[dano]

Well that sucks. Fuel pump driver was an easy fix. Darn it for him.

 

[riphip]

Repairing the relay on the control board is not hard if you know how to desolder & resolder.

 

[BlackCoffee]

I replaced the control board relay and it was not hard. I used this video for reference. If it is bad, it should be obvious on removal of the board. It will look burned. Anyway, with the age of your Expedition, it can't hurt.

Here is the video:
I got the relay of Amazon: https://www.amazon.com/gp/product/B07BMSDQ39/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It's not that hard. I took photos of the fuses before I removed them all.

 

[texasscot]

I replaced the control board relay and it was not hard. I used this video for reference. If it is bad, it should be obvious on removal of the board. It will look burned. Anyway, with the age of your Expedition, it can't hurt.

Here is the video:
I got the relay of Amazon: https://www.amazon.com/gp/product/B07BMSDQ39/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

It's not that hard. I took photos of the fuses before I removed them all.

Very useful post thanks!
I have just done mine. I had the increasingly frequent engine stall which was getting dangerous to be honest.
Anyways I took pics to show what I found and to maybe help others. One of the solder joints of the center soldered relay looked darker and kinda bubbled but the relay body looked perfect, unlike what others have seen. I bust open the relay and the inside also looked totally ok. It seems that my fault was a dry solder joint caused by whatever.

The hardest part was wrestling off the cover from the power lead at the far side of the fuse box so I’ve posted a pic of it to show how it’s attached. Visibility is poor back there and it helps if you’re a contortionist.

Not too hard a job overall but I found the unsoldering to be difficult. I used a suction pump thing but getting all the solder of was tough so I ended up breaking it off and clearing each hole one at a time. Nasty.

Putting it back together and into the truck was easy as you can see how it attaches.

anyway it’s now firing up and running but of course with intermittent faults you never know if you’ve fixed them, until you remember that it used to be a problem lol.

thanks for everything, everyone. Happy 2021.