I was driving home from work today and noticed that my volt meter was almost to the high mark unless I was at idle. I tested it with a Snap-On tester and sure enough all the way pegged out. The multi meter said 15.5 volts at the battery terminals. I have a new high out-put alternator from Auto Zone, new Mopar performance PCM for a 5.9. I went by Auto Zone and of course the battery tested bad so in went a new one and he rechecked the charging system which said was good at 14.2 volts, (it was overcharging before the battery swap).
By the time I got home it was overcharging again which will surly kill the new battery. I'm running a 92 drive line behind the 5.9 with a 94 PCM for a Ram. The 90 amp alternator was put on to help with a frame mounted fuel pump, trans cooler fan and fog lamps.
I guess the voltage regulator is in the PCM so it probably will not be a problem with the alternator and I'm suspecting a Mallory fuel pump that gets progressively louder with heat could be drawing to many amps, or am I chasing my tail?

 

I don't get it. I replaced the pcm with a known good stock pcm, I replaced the alternator with a known good used alternator, I've checked all ground connections and cleaned the battery cables. I'm still getting an overcharge problem. I disconnected the battery ground and connected a test light between the cable and post, I get a sort of bright light for a second that dims rapidly and I can make it go away if I pull the battery draw down fuse, (what ever that is).

Any ideas? I guess I'll try and replace the suspect fuel pump tomorrow.

 

i did find an artical on making an external volt regulator. i think it will by pass the computer regulator. i think this is it. https://dodgeforum.com/forum/1st-gen...onversion.html

 

Moe, I thought that was going to work in fact it did for about two or three minutes. I shut the truck down when I saw a charging voltage at the battery of 13.6 to 13.8 and did a temp. job of zip tie the wires back up till I could get so new conduit. I fired it back up but now the in dash volt meter is bouncing from mid high to very high and a multi meter check at the battery is still almost 16 volt. What the hell could be going on when I've completely overlayed all the field coil wiring and by passed the PCM??? I'm flabbergasted and don't know what to check anymore.

 

i am sorry i have not tried that mod. i wish i did know more about electronics. but a wild guess is some kind if feed back to the computer. allpar has some info on this subject