Hi guys, Rotten here from east Alabama, got a problem that I can't solve on my own, so I'll throw it to y'all, and see if someone can shed some light.

1991, non-ic. The problem started when the charging system started to cook (smoke, boiling sound) the old battery that was in the truck when I bought it. The gauge would read in the section by the number 18(!)
So I took the battery out, put a brand new one in, figuring maybe it was a dead cell. Nope. With the new battery, it read higher! The guy at the parts store put his tester on it, it was charging at 18.5v.
Ok, first thing I thought was voltage regulator, right? Put a new o e on, and now the volt gauge bounces between 14-16 volts, averaging around 15.5v, enough to still boil my new 100 dollar battery
Went and bought another voltage regulator from another store, same results. The gauge bounces around, and the truck still overcharges. If I take the positive cable off the battery while the truck is running, it stops moving, and stays around 14v.
Im no electrician, but I can learn! Any insight would be appreciated, the truck has been awesome except for this issue, which started about a week ago. I know I'm still new here, and can't contribute knowledge like some of you guys, but I'm here for the long haul. I do have access to a multimeter, so if y'all want me to go poke wires and tell what I find, I can do that!

 

i take it your running external voltage regulators? i tried running them on my truck and never had much luck, i switched to a transpo internal regulator and it fixed my charging issues....i can prob., find the box and give you the part number....i just gave it to another guy on here not six months ago....it definitly sounds like you have a regulation problem to me....

 

So a stock replacement regulator is no good? I sure don't want to shell out for a new alternator, if I don't have to.

 

The stock replacement external style is fine. You need a new alternator believe it or not. I went through the same thing on my 1989 non-ic and boiled two rotten egg smelling batteries before figuring it out...

 

Sometimes you can have the rebuilt for cheaper....

 

check the ground strap that connects the chassis to the engine.
they usually rot away

 

Well, I'm going to put an alternator on tonite. I can find no other reason for the problem. I'll report the results later this pm, thanks for all the ideas guys!

 

How does an alternator "override" a voltage regulator?

 

There are none.

 

I would check the connector for the voltage regulator. Look inside it and see if it is green. This has happened to me with the same results. I have taken contact cleaner and a wire contact cleaner. Also take a pair of pliers and squish the terminal ends, so it fits tighter. Apply dielectric grease and put back on. This little fix has worked for me now for two years.

 

Ok. New alternator is on, started it up, and the problem remains the same. No change at all. The voltmeter still bounces, the battery is still being overcharged. It's dark now, but tomorrow I'll take a closer look at the connector for the regulator, but it looked good to me, but I will check it, since at this point I am at a loss. If you pull the positive battery cable off the terminal while the truck is running, the voltmeter reads way high, like 18-19 volts, but it doesn't flicker. With the battery cable hooked up, it's bouncing between 15-16 volts.

 

ok, buddy i just ran out to the garage and grabbed the box its Transpo P/N [IN8315] its just a little circuit bored looking thing that has four wires on it....you install it under the back cover of your alternator and run a 12v wire to your field post when the key is on....it can't have constant power just when the key is on....but im sure you know that already....you bend your stock two field terminals out of the way and tape them up...it has a great instructions with it in the box that even i could figure out....help this helps...pulling the battery cable off while the engine is running isnt a good idea, this has been known to fry electrical components....i fried a computer doing that on a chevy years ago....if you put this regulator on your truck i'd almost promise that it would fix your problem....

 

My 89 has a ground strap.... don't see one on my 93 though.

 

Twisted- thanks for the info, and if I am forced to go that route, then I'll try it, but I am trying to figure out why the stock replacement parts are not doing their jobs? Why would putting a regulator in the alternator be any different than the way it is now?

 

Checked and cleaned the connectors on the voltage regulator, no change.