The other night, I parked my 2002 F-350 7.3 4X4 in my garage and the next morning it wouldn't start. As long as ignition was in crank position, it would run. As soon as ignition back to run position, it would quit.
I have been a diesel mechanic all my life, and run a 24 hour road service business, so I have run across a lot of different problems, but I gotta say, this one has me perplexed.
I checked all the fuses first and they were all good. Next I checked to see what else wasn't working. No glow plugs, but wts light was coming on. No fuel pump, no radio, no power windows, no communication to dlc, no switched-power (#71, red wire) to ecm. Ignition switch seemed to be fine, but replaced with new one anyway. Checked for power to fuses. Had no power to #22 & #23 (engine control), #42 (delayed accessory), and #36 (pcm keep alive).
I disconnected the batteries and reconnected them, hoping for a miracle. Tried starting again to no avail. But after cranking for a few seconds, it quit turning over. Checked all fusable links that I could find. Had power to starter relay. Removed fuse box, took apart and found starter circuit in printed circuit burned up. Repaired as needed, checked all other circuits in printed circuit, put fuse box back in, had starter working again, but still no start.
I was running out of time, as it was almost time to leave for christmas with inlaws 500 miles away and wife was getting nervous.
I cut ecm wire(#71, red wire), spliced it to switched power, which made a couple of things click, jumpered the fuse box as needed to get power to fuse #22, 23, 42, and 36.
Now I had power to all systems, but still won't start. Replaced pcm, and fired right up. Check engine light on, no communication with glow plug circuit. Glow plugs work fine. Tried clearing code, but code clearing kept failing.
At this time, I either have to tell wife we're not going or take a chance and head out. Ran it around town for a couple of hours and seemed fine. Headed out, and it ran like a watch the whole trip. It was -20 F at inlaws, and started every time. Came home, and is still running fine. Still has check engine light, with glow plug code, of course.
The other thing that's new is when idling in the cold, it will idle up to 1000 rpms until brake pedal is pushed then it idles down. I assume this is how it is supposed to run, but I've had it for 5 years and 85000 miles and it never did before.
Anyway, now that I'm home, I need to fix it right, and I'm not smart enough to find the problem. I'm betting it's something simple, but gotta find it before I can fix it.
I appreciate any help I can get. I've probably forgotten half the things I checked, but am open to any ideas.
Thanks,
ccrscubby

 

The high idle is normal. Is it possible it was a PCM issue to begin with not commanding relays to close feeding the above circuits you jumpered? Have you tried removing the jumpers and checking?

 

I guess I forgot to mention that even after replacing pcm, still had same problems with jumpers removed. Reinstalled jumpers to make everything work.

 

Fuse 22 &23 power off of term 87 of PCM relay. term 85 of that relay grounds thru the PCM diode to G100 on firewall. term 86 receives power off of I1 term of ign sw which is rd/lg wire.

Fuse 46 uses the same ignition terminal to power it via a splice that runs off of I1 terminal as well.

Mega fuse 64 is the only thing between it and the all time hot source that feeds the ign sw term I1, Well B5 on input side of sw.


Fuse 36 should be hot at all times from a fusible link. Incidentally, it is also the same power feed that ultimately becomes fuse 22 & 23.


I am fairly certain those fusible links are the sames ones that power the starter circuit so I do not think those are prob bad.

Fuse 22 also normally pwers wire 71 &97 on pcm, fuel pump relay which is built internally in fuse box on 2002, switched power to GPCM, and AIH

Several months ago, another member had something similar on an 02 that turned out to be a burnt harness up in the intake valley. He never did come back to report the end but that was where he was. It seems as though it goes thru the 42 pin connector on the Drivers vc. I am not saying that is your issue but just throwing it out there. It was definitely 22,23, 45. Do not remember 36 though. He also had a backfeed on dashcluster lights with switch off.

This is that post. If u are like me, pics are worth a thousand words so the schematics for 02 are on page 7

https://www.ford-trucks.com/forums/1...key-off-7.html

 

That might help. I'll go chase those wires down and see what happens.
I'll post progress as soon as I know. Thank you.

 

I said GPCM b/c u said it had glow plug code...IS this a california truck with the Glow plug module or does if have the glow plug relay?

 

it has glow plug relay

 

Finally got a chance to work on this junk. The cel was coming on because the pcm I put in needed to be flashed. Did that and that problem taken care of.
As far as the electrical problems, I unplugged every connector, cleaned and blew them out, and put new dielectric compound on them. I unhooked all my jumper wires, hooked up batteries, turned key on and now I have power to everything except fuse 42 (delayed accessories).
I'll troubleshoot it in awhile and post problem if I can find it. If not, I'll be back here getting ideas.
Thanks for the help.

 

After checking everything out, I have determined the fuse box circuit board is burned in more areas than just the start circuit. I fixed the start circuit, but the delayed accessory circuit isn't quite as easy. I think I'll just jumper it so it works and hunt up a fuse box asap. Thanks.

 

Thought I'd update this post in case the next guy that has this problem can save some gray hairs. Turns out, the instrument cluster was the problem with delayed accessories, etc. Put a used cluster in and problem went away. Tried having it repaired, but ended up not fixing the problem where I sent it, and have had no luck finding anyone who can repair this kind of problem with ford cluster. Anyway, it's been working great for over a year now. Thanks for all the input, and hope this helps someone that has same problems someday.

 

Glad you came back to give us an update. Yes a yr later but better then not giving us an update. Many threads go unfinished and leave us in the dark of what eventually fixed the problem.