Aftermarket regulators are often crap.

Also check to make sure that the field wire from the regulator is not shorted to ground. The regulator regulates by pulsing the ground, so if that wire gets chafed and shorts to ground you have an out-of-control alternator.

 

What he said. Check all the wires coming to the regulator, and make sure the grounds are there and connected well. I added a strap from the block to the firewall and to the frame. I have 0 gauge welding wire for the ground to the block.

 

I've blown a couple voltage regulators and a couple batteries in mine too. Usually the voltage regulator blows if you have a dead short in a pretty major wire or switch. On the early nineties dodges if you bump the headlight switch sideways with your knee it will short out and blow the regulator... I know, done it a couple times.

 

I gave up and took it to a good local diesel shop. Couldn't find any bad grounds, etc etc. I'll update when I find out what was wrong

 

Dude im havin the same exact problem replaced the regulater and still have 17 volts. im thinkin maby another regulater?? sorry to hyjack the thred.

 

Well, here is the final word on this problem- the truck doesn't overcharge the battery anymore, but the electrical system still pulses at idle, but never exceeds 14.8 volts. It's slightly annoying to watch the gauge at stoplight and such, but it's not affecting driveability, so what the hey. Thanks guys for all the advice, I appreciate it!

 

ARRRRGH!

Back to square one, she ran as described above for about a week, until this AM. It's bouncing back and forth between 14-18 volts again I'm at a loss, again. I was planning on driving to the **** creek machine gun shoot next weekend, about 550 miles, but if this problem persists, I don't know if I want to take it.

 

Maybe a stupid question , but are you relying on the truck's voltmeter or have you checked this with a separate voltmeter at the battery? Just a thought, if so, maybe you have a faulty connection at your voltmeter...good luck Mark

 

Well did you ever replace the Alternator? I didn't see any mention of that.

 

Yes, I have a multimeter, and it reads 17-18 volts. You can tell also by the headlights and dash lights getting super bright as the gauge moves higher.

 

Yes, I mentioned this on the first page, but it may have been at the bottom of the page or something.

Here is a rundown on things done so far:
new battery
(2) new voltage regulators
new alternator

after all this, the voltmeter still pulsed slightly at idle, but the voltage never broke 14.7v I took it to a mechanic who works on cars and big rigs, a guy I know who has done good work in the past, to see if he could straigten it out, he said he couldn't figure it out, and since it wasn't overcharging anymore, to not worry about it. Well, this AM, it started to overcharge for 3-5 seconds, then go back to normal for a minute or two, then overcharge again.

It would help me if someone could lift thier hood, and see how many wires are coming out of their voltage regulator connector, mine is three pronged, but only has 2 wires coming out, I'm wondering if this is correct?

 

2 is correct.,..I hate to say it, but maybe you got a bad alternator, or the problem that was causing all this caused the new alt to go bad...hang in there, because we know the system works when all the components are good...good luck Mark

 

What brand of regulator are you using?

 

I tried one from advance auto, and one from autozone. The autozone (duralast) is currently on the truck. Both behaved exactly the same when I put them on. Which is to say, pulsing at idle, smoothing out at speed. The one on the truck is now acting up, and allowing the alternator to overcharge

 

On the passenger side of the engine there is two connections for the alternator. Have you looked and taken these two connections apart, looking for the green monster?