93 12v 5.9 with external voltage reg installed.....works but i am getting a high voltage pulsing problem 12v--16v at idle pulsing in 1 second intervals then faster at higher rpm ....also get a battery light but I know that might be common with this application ....new alternator 09 and im on my 3rd reg ...a napa part.. not mopar ??? does that matter and it is wired correctly as per other bloggers posting an .....another thing is when I increase the load on the battery fog lights,bed spot light ,ac/heat fan it seems to lower the pulsing....any idea's???????

 

when it is cold the grid heater will cause the tach to jump.

for DC, the only time that this would happen, power wire grounding out somewhere on the truck, or voltage regulator bad, I believe the regulator is part of the ecm, I have heard of people by passing the ecm to stop this problem.

 

thanks cummins guy I am currently /slowly re-wiring all the chassis wires to the rear of the truck due to old and broken wires and I hope there is some kind of intermittent grounding problem that I will locate ....a few more days under the truck and we will see......p.s I already by-passed the ecm regulator and have a external.... and i have tried 3 different ones napa,and2 other types not sure of brand .....

 

Best regulator is the Mopar Blue.

Cost a couple $$ more but will outlast the others.

 

cowboy I might just give that a try after I rule out any grounding issue ......thanks

 

the biggest grounding issue with these trucks is the wire from the negative terminal to teh core support. It is grossly under sized from teh factory and causes all sorts of crazy issues with electrical. I would replace that with some heavy gauge wire, Even if this does not solve your issue it will help prevent future issues.

 

will change that ground tonight to some quality 3/0 welding cable and hi-press crimp the terminals ......I did find that on the positive terminal while trucks running I lifted 1 wire of 4 at a time and found 1 a #8-6 black that goes deep onto the tapped to hell harness that when disconnected solves the problem and truck keeps running volts stable off to about 14.5 ish .....but when you shut truck down it needs to be reconnected ...it was late last night so Im gunna dive back into it tonight again and narrow it down......

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GOOD NEWS AND BAD NEWS.........CHANGED THE MAIN GROUND ,RAN ANOTHER GROUND TO TRUCK BODY AND CHASSIS, PULLED ALL THE FUSES AND REPLACED WITH NEW ,RAN A NEW #10 GROUND TO THE EXTERNAL VOLT REG HOUSING AND,PROBLEM SOLVED ..NO MORE PULSING STEADY VOLTS 14.5-14.8......BUT THE BAD NEWS IS AS I CHANGED ALL THIS CRAP OUT ONE BY ONE i SHOULD HAVE RAN TRUCK EACH TIME TO SEE WHICH ONE WAS CAUSING THE PROBLEMSO TAKE YOUR PICK..... #1 I THINK IT WAS THE MAIN GROUND CHANGED TO A 3/0 >> #2 THE FUSES WERE ALL OXIDIZED AND OLD AND MAY HAVE BEEN CAUSING HIGH RESISTANCE BUT ITS FIXED