Kris Harrison's 1997 Diesel Issues

[Gary Lewis]

Brandon/Bruno2 sent me a text message yesterday asking questions about the PCM on the 1997 F250 that his son, Kris/Bruno2son, has. Apparently it shuts off at the least opportune times, and may not be willing to start for an hour, or a day, or a week.

So I agreed to find the '96 EVTM and scan in the pages for the diesel that are in it. As it turns out there's only one diesel listed in it - a 7.3L DI w/a turbo. So I scanned those pages in. But, since I don't know where to put them in the Documentation part of the site I'll put them here. Hope they help.

[85lebaront2]

Gary, John Gleason (friend I did the 10.25" disc brake conversion for) has a 1995, same engine. He has had a couple of issues with his, one that blew his mind was oil low, apparently the oil level can get low enough that the HPOP (High Pressure Oil Pump) gets air into it and the hydraulically operated injectors don't open fully if at all.

Another common issue on these is the crank position sensor with no signal, the PCM has no reference so it won't trigger the injectors. A further item, the wiring for the injector solenoids and glow plugs runs through the valve cover gaskets and they are known to burn the connectors due to the high current for the glow plugs.

I would start by taking a good look at the connectors on the outside of the valve cover gaskets and make sure they aren't melted or burned.

These engines are a "drive by wire" system, no throttle cable of any kind, accelerator pedal operates a resistance box that tells the PCM how far the pedal is depressed.

If you look at the wiring you will also see the IDM (Injector driver module) it is an aluminum box underhood just behind the PDC on the left inner fender.

[Gary Lewis]

Bill - I sent Brandon a link to this thread, so hopefully he'll see your helpful response soon.

[85lebaront2]

That was the idea, post something that will hopefully help.

[grumpin]

What Bill said, I know people who’ve had rough running PSD’s and an oil change cured it.

[Bruno2]

I have checked the oil level and all of the basic failure points regarding the 7.3. I even swapped the cam position sensor just for giggles even though I knew that wasnt the issue. The tach works when it cranks . When they don't on an OBS truck it is typically the CPS. The finger is pointed at the PCM. It is showing intermittent power failures. I havent tried swapping in an IDM. I have one on the shelf atvthe shop.

I am pretty sure it's the PCM. I an goingbto pull it this weekend,  open it up and give it a visual inspection.

[Gary Lewis]

Brandon - Don't miss that you can download that file.

[grumpin]

Also might try fresh oil.

[Bruno2]

Well today I set out to nail down the electrical gremlin. We discovered fuse #9 (completely different than Mambo #9) was blown.  Although this had never happened before I suspected it had something to do with it.  While ohming the fuses in the UHD PDB I got a funny reading on #9. It started to give the audible indicating the was a complete circuit. However, it stopped almost immediately.  I pulled it to findbthe infamous hanging

[Gary Lewis]

Brandon - I think you posted before you were done.  And I find it hilarious that you left us hanging by saying "I pulled it to findbthe infamous hanging"......  

But for the others, he found a wire that was power from the PCM Power Relay to the PCM and other things that was bad and grounding out.  Apparently that was causing the fuse to blow and stop the truck.  He said the truck started and he was driving it home from the shopping mall's parking lot where it quit last time I knew.

[Bruno2]

The Garagemahal somehow left out about 4 patagraphs and a couple of pictures.  This is like the 3rd time this has happened.  The last time I remember wasxa tailgate thread. It takes the wind out of my sails when it happens. This phenomenon turns a lengthy fun story into see spot run because I am scared it will happen again.

I will try again later.

[Gary Lewis]

Sorry!  Are you doing that on a phone?

[Bruno2]

Yes