[Longrangehunter]

Good evening, I've done quite a bit of searching of the forum and troubleshooting, and I've successfully made it worse.

I have a 2001 Ford Excursion 4x4 with the 7.3 and approx 200k trouble free miles on the clock. Starting about a month ago, it died randomly on me riding down the freeway one day. I was able to knock it in neutral and get it restarted, but it died a couple more times on my trip. This is the first I had experienced anything like that.

I went home and checked some things under the hood and settled on loose battery terminals, cinched them down, and haven't had an issue until this week when it died in town at a stoplight on me.

Knowing the CPS is a common issue with these trucks, I ordered a motorcraft (dark blue one) and installed it. I also checked the IPC while in there, no oil in the plug, and checked the wiring harness by the driver side valve cover for chafed wires. All good on both fronts.

Truck started fine, but about 10 minutes into my test drive it started dying at stop lights when I would try to accelerate. The stalling problem was much worse and more frequent than before. Eventually I got to the point where she will not restart, and with the ignition keyed on, it will not accept an OBD2 code reader (I tried 3, one of those Amazon wifi ones, my edge monitor, and the AutoZone reader).

I'm wondering if the PCM is toast? Or was my motorcraft CPS a dud out of the box? (Bought from Amazon, but it was sealed in Motorcraft packaging, had good reviews, and seller states is genuine) Any help is appreciated because I have a 9k lb boat anchor right now!

Thanks

 

[Longrangehunter]

Making diagnostic progress, my "wait to start" circuit comes and goes. Once in a while the key cycle is effective and the PCM kicks on, but more often the service engine light kicks on with no "wait to start".

The PCM is obviously getting power sometimes and not others. I know the fuel bowl heater/fuse 30 is a common issue, but if that were the case, why would it work sometimes?

I tried unplugging the EBP valve, no improvement. Could the CPS cause the PCM to not power?

 

[John in OkieLand]

Wild shot in the dark, just watched a video on a IPR valve that is Temperature Sensitive.

have you installed a Motorcraft IPR ?

IPR coil opens when hot

 

[Longrangehunter]

Wild shot in the dark, just watched a video on a IPR valve that is Temperature Sensitive.

have you installed a Motorcraft IPR ?

IPR coil opens when hot

I have not replaced the IPR, but that's certainly a recurring item in my research.

Would a bad IPR have any hand in my lack of PCM/Wait to start when I key on the ignition?

 

[John in OkieLand]

I have not replaced the IPR, but that's certainly a recurring item in my research.

Would a bad IPR have any hand in my lack of PCM/Wait to start when I key on the ignition?

No, the IPR is the last in the chain to get it started, assuming the Injectors are good.

I sent you a PM / conversation this forum calls it.
top right of page, click on your Avatar, then Conversations

 

[John in OkieLand]

here is a trouble shooting chart

 

[klhansen]

You may have an ignition switch that's intermittent. There are 4 separate switches in it and on may be going bad (the one that powers up the PCM.) It could be a loose/intermittent connection in the circuit powering the PCM.
Has anyone used an add-a-fuse stuck into the fuse box socket? That can mess up the contacts for fuses.
Here's some info that may help you to check the ignition switch and circuits.

 

[John in OkieLand]

Just in case someone wants to combine the two pages, I did just that and posted here.

 

[Longrangehunter]

Just in case someone wants to combine the two pages, I did just that and posted here.

Thank you very much for all of your help, and for your PM!

After chasing wires around, ensuring that connectors are tight, ensuring continuity, etc. I've come to the conclusion that it's not fuse or wire related, because it does work part of the time (so it is getting power).

Rather than continue to throw time and money at random parts and "maybes", I am shipping the PCM off to Diesel Technology of Chattanooga for bench testing. I'll update with their findings. If it tests good, we're back to throwing darts at the wall.

 

[olddieseldude]

I'm not reading that you read any codes. That would help a alot.

 

[Longrangehunter]

I'm not reading that you read any codes. That would help a alot.

Can't read codes when the PCM won't boot. I explained that I tried 3 different code readers.

 

[klhansen]

Check your cigarette lighter fuse. It's shared with the DTC connector and if popped, you won't be able to pull codes.

 

[mwaters_120]

Check the relay for the PCM , test it if possible and or switch it with another one and see if the problem is and relay switched causes another problem elsewhere.

 

[olddieseldude]

Can't read codes when the PCM won't boot. I explained that I tried 3 different code readers.

Sorry, my bad.

 

[Robert Dez]

Just wondering, because I always start with the most obvious. Have you had your batteries tested? Actually had that happen to a non diesel vehicle I owned. Intermittent installing.

 

[jpliss]

Usually a ecm / pcm failure does not result in intermittent issues.

I would verify with a DVOM power and grounds.

Ignition switch issues which are common will show up in these tests.

You can perfrom these tests with out the ECM / PCM installed and I would take some time checking them.

 

[Longrangehunter]

Heard back from Diesel Technologies of Chattanooga - the PCM was bad and required rebuilding. It is currently in transit back to me, and I'll update once I have a chance to install and test drive.

 

[Longrangehunter]

Got to installing the new PCM and noticed the plug is cracked.... Guessing that could be a major source of issues.

Truck seems to run fine with the rebuilt PCM, but seems like a ticking time bomb with the plug the way it is.

 

[klhansen]

That crack may just be cosmetic. As long as the seals around the wires are intact and the crack doesn't intersect the wire sockets, you should be fine. Maybe seal the crack with some silicone sealant, but you'd have to clean it well and get access to the connector. It isn't in the most accessible spot.

[on edit] It looks like the crack is just below the silicone rubber wire seal. Possibly someone got heavy handed and tried to pry the connector loose without loosening the bolt. Here's a pic of a PCM connector that I partially disassembled so show the components. The blue thing is the wire seal and the outside of it seals against the body where yours is cracked. Water can definitely get in there.