96’ bone stock F250. Been having what I would consider typical CPS problems (quick cut outs, and died a couple times but restarted no problem). Then Tuesday ran great for a couple hours then went to leave again a few hours later and NO START. Fired up once for a split second but that was it. No tach so swaped in a spare CPS and exact same thing. One fire up out of a bunch of attempts. Paying more attention to the tach notice it works some crankings and not at all on others. Assuming wiring prob now I test CPS pigtail, ground-good, 5V-good, next wire is different every time 6v 4v 3v 5v. Checked my 99’ and found it’s supposed to be battery voltage. Googled wiring diagrams to help find the trouble spot. Found that diagrams are slightly wrong, they say the green wire in question goes through pin #39 in the 42 pin connector and ends at pin #21 at the PCM. The #39part is right but it ends at pin #49 at the PCM, not #21,21 is an empty hole. That one Ohm’d out perfect but ironically the other two wires were high at 25 Ohm’s. Jumpered a wire from the battery + to the unplugged #49 PCM connector and got perfect battery voltage at the CPS connector.
So do I assume PCM is not putting out the Battery + its supposed to at Pin #49 ??? =New PCM
Is there a way to very carefully “hotwire” the PCM (with it unplugged) on the proper pins to check/verify the voltage coming out of pin #49 ???
Would the PCM out of my 99’ work in the 96’ just to see if it will run, without blowing something up ???
Could I run a wire from the battery+ and splice it into this wire to supply the needed voltage ??? If so would I need to cut the wire going into pin #49 to keep from back feeding the PCM and causing more damage ???
ANY help is greatly appreciated. I NEED THIS TRUCK RUNNING.
So do I assume PCM is not putting out the Battery + its supposed to at Pin #49 ??? =New PCM
Is there a way to very carefully “hotwire” the PCM (with it unplugged) on the proper pins to check/verify the voltage coming out of pin #49 ???
Would the PCM out of my 99’ work in the 96’ just to see if it will run, without blowing something up ???
Could I run a wire from the battery+ and splice it into this wire to supply the needed voltage ??? If so would I need to cut the wire going into pin #49 to keep from back feeding the PCM and causing more damage ???
ANY help is greatly appreciated. I NEED THIS TRUCK RUNNING.