PCM fail

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PCM fail

Postby cougar » Fri Mar 17, 2017 12:32 pm

Is their anyone out there that repairs or exchanges 92 - 93 automatic PCMs?
Mine is acting up. No grid heater preheat, only starts working after the engine starts.
Also the the alternator over volts after start up for a few seconds, then the wait to start light blinks on, the voltage goes to normal and the grid heaters start cycling down normally. Why the alternator is over volting is strange, it is on an external regulator.
RIP 91.5 W250 5 speed. The great experiment.
92 W250 HD 47RH with Compushift. Upgraded H1C to 60/60/16, modified fuel pin, and DAP 7X.010 injectors.
01 2500 "the work truck".
cougar
14mm rotor
 
Posts: 875
Joined: Sat Apr 18, 2009 3:31 pm
Location: The Valley of no concern, AK

Re: PCM fail

Postby cougar » Sun Mar 19, 2017 8:08 am

In the mean time I replaced the crank position sensor (what a pain that was) and removed the auto shutdown relay from the PCM. I noticed when the alternator was in over voltage, the tack wasn't working. Classic crank sensor fail. I also rewired the relay to prevent any future PCM or crank sensor fails from the charging circuit. Don't know about my grid heater yet. I'll have to wait for a cold start.
RIP 91.5 W250 5 speed. The great experiment.
92 W250 HD 47RH with Compushift. Upgraded H1C to 60/60/16, modified fuel pin, and DAP 7X.010 injectors.
01 2500 "the work truck".
cougar
14mm rotor
 
Posts: 875
Joined: Sat Apr 18, 2009 3:31 pm
Location: The Valley of no concern, AK

Re: PCM fail

Postby cougar » Sun Mar 26, 2017 10:12 am

Put in my spare PCM yesterday and all the important things are working again. My spare was the original to the truck that had a lot of problems. I fixed a few by re-soldering some cold solder joints and replacing a couple bad caps. Voltage regulator and OD still don't work, but I have those bypassed with an external regulator and the Compushift
RIP 91.5 W250 5 speed. The great experiment.
92 W250 HD 47RH with Compushift. Upgraded H1C to 60/60/16, modified fuel pin, and DAP 7X.010 injectors.
01 2500 "the work truck".
cougar
14mm rotor
 
Posts: 875
Joined: Sat Apr 18, 2009 3:31 pm
Location: The Valley of no concern, AK
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