I’ve got a 93 F-Superduty with a Powerstroke swapped in from a 97, all of the 97 wiring is in the truck so it essentially a 97.
a few weeks ago I got the crank no start no tach, I replaced the cps with “genuine ford” from Amazon and it was good for 2 days then it quit on me while driving, when it quit the tach was fluttering up and down but running fine for a few minutes then lurched a few times and quit, this time I bought one from the dealership. Grey with purple o ring. I’ve been having issues ever since. The first time I started it it started and died, then it drove 4 minutes and died and then It ran fine a few days now we had a big rain overnight and it’s crank no start again. I’ve checked the wiring back to the pcm and it ohms out perfectly.

I checked the cps plug and I have 65ohms to ground on pin A with the glow plug relay on and then 20ohms once it turns off which is apparently supposed to ohm out to a maximum of 5 ohms. Pin B shows the expected 5 V but pin C was showing only 3 volts with the key on instead of 12. I had the pcm out and it looks like it’s been getting wet, I blew it out and tried to dry any moisture out and now when I check that pin C I seem to have 10 volts or so.
I’ve read hundreds of threads on CPS problems and PCM issues and none of them seem to be what I’m looking for and I can’t figure out where the PCM grounds to anyway.

I did clean all of the grounds under the hood on the fenders very well and reinstalled with zero change.

I’m feeling defeated and this truck has a pile of firewood it needs to be delivering that keeps getting pushed back while I mess around with it please any help is appreciated. I’m looking for PCMs to try in it but nobody I know has one of these trucks to test.

 

Bump, no ideas yet?

 

windshield leaking?
cab grounds at kick panels at your feet in can get rusty
PCM grounds to the cab when mounted IIRC