2002 F250 No start hot, now no start period

[wagman]

Newbee to the forum as a poster. Been researching the site for a long time. I've seen many folks with similar problems, so let me lay out my issue.
I have a 2002 F250, 7.3L PSD bone stock, 235K miles. A few months ago I experienced a stall when hot (normal operating temp). A few hours later it started back. Thought it was a CPS at first, but since it started, I just drove it. Stalled again, no-start hot, but restarted after hour cooldown. Took it to a Ford dealership (Smith Ford, Conway AR) where they replaced an oil pressure sensor for $500. Truck started (cold, obviously) and it worked fairly well for a few weeks. Then it started having problems again. Starts cold, runs fine, but wont re-start hot, occasionally dies when driving. I've taken it back to the dealership several times where they are unable to repeat the problem. Finally quit alltogether. No restart at all. New CPS, new oil pressure sensor, new batteries. Fresh oil and filter change, fresh fuel filter change. Unplugged the oil pressure sensor. Still, no restart. I get the normal glow plug WTS light with key roll-on. I've seen lots of posts where folks have similar problems, but not one that tells what the problem turned out to be.
Ordering an AE scanner w/Ford bundle Monday. Looking for HPOP pressure, IPR duty cycle, RPM (to verify CPS is working). Is there anything I can look for to verify the IDM is working properly? With the WTS light working normally and no blown fuses, I am assuming the PCM isn't dead (doesn't necessarilly mean it's working properly).
Any help would be greatly appreciated.

[wagman]

Starting to think this thing is the IPR. The best way to descibe the problem is to break it into two divisions. 1)Stalls/no start hot; 2)No start at all.
During failure 1, the truck would start cold without any problems. I'd drive it for 45 minutes and if I shut it off, it would not restart. It would finally stall while driving until it finally stalled and wouldn't restart whatsoever. The coil for the IPR, in my estimation, works cold, but fails hot, a common failure for coils/solenoids.
Will have more info later.

[NoRalPh]

Really does sound like a CPS, that's what they do, Fail Hot and "recover" as it cools down. You've changed that I see so, maybe the IPR but, once you get the AE you'll know for sure!

More than the coil failing I think the IPR craps-out with crud. IF you get stuck again before the AE comes, try rapping on it to see if it's just stuck...

When you say you've tried the "oil pressure sensor" unplugged and even replaced, you're talking about the ICP? (for $500 I assume so...)

[wagman]

NoRalPh, Yes, it was the ICP. You're all over it!
The truck is two and a half hours away, or I'd go rap on the IPR right now!! ;-)
So anyhow, I'll be sure to post back, once I have run the issue to ground.
I really appreciate your reply. I love this forum.

[wagman]

OK, got it fixed, finally.
It was the solenoid on the IPR. I bought a new IPR from Autozone and took it up to the truck (2.5 hours away). I pulled the solenoid off the old IPR. Took five minutes. I took my Fluke meter and ohmed out the old one and then ohmed out the new one. New solenoid was 10 ohms. Old solenoid was 0 ohms (short).
So, rather than pulling the old IPR 'stem' out from the back of the HPOP, I chose to only install the new solenoid. Wha-lahhh!!!! She started right up and I am flying high. I've driven the truck all week and it starts without so much as a hiccup. No more hot start failures.
Now, I purchased the Auto Enginuity scanner with the Ford bundle. What an amazing tool. So, fellow PSDers, if you're in the central Arkansas area and need a hand, I might be able to help out.