Electrical Problem again

[jdavidsmi]

Well, I thought I had fixed the electrical issues with my truck, but not. A couple of days ago on the way to town I noticed the volt meter was dropping from 13 volts down pass 12 volts and by the time I got to the auto parts store, I was not sure I would make it in. The battery was all but dead.
I thought the new alternator had died, it's only 2 months old, but the alternator and battery both tested OK. but not the voltage regulator, so I installed in a new one, still would not charge. By now the battery was dead and had to be jumped to start the truck. The store clerk got a heavy duty one and everything started working. I completed the shopping I need without any issues.
On the way home the volt meter started climbing up to about 18 volts by the time I got home. Its a 15 to 20 min ride. To day when I started it up, the voltage started out 12. 67 with my DVM at idle. As the truck idled the voltage started climbing, within 15 min it was back up to 16.97 and climbing, I shut it down.  

Battery was fully charged, and nothing that I know of was on.

Is it possible I have too heavy duty voltage regulator??   Is that even possible??

[Gary Lewis]

First, I've just changed my browser allegiance to Edge as with Chrome I can't see your signature, and that information is important.

Anyway, I don't know if there is such a thing as too heavy duty of a regulator.  But, something sure is wrong.  You should never see over about 14.5 volts, and if you continue driving it with higher voltage you'll boil the battery dry and probably blow some bulbs.

Since you had the regulator off it is possible that the ground on the regulator is bad.  It is supposed to ground to the fender via the two bolts that hold it on.  So I'd start there, and if that doesn't do it then I'd take the regulator back.  

[jdavidsmi]

Gary, thanks for the answer. I just cleaned both contact points where the bolts are for the regulator, plus I added a ground wire between one of the bolts and a known good ground. Did not make any difference, as everything warmed up the voltage went up.

So back to NAPA Monday.

Is there something I need to change so you can see my Signature?

[Gary Lewis]

Good plan.  Gotta be the regulator.

I see your sig perfectly using Microsoft Edge as the browser, but not when using Google's Chrome.  So, it isn't you and I don't think there's anything than can be done to make Chrome work.  

[grumpin]

It sounds like the new voltage regulator isn't controlling the output from the alternator.

Or when the VR gets warmed up it loses control of the volts.

I use Firefox so I can see the signatures.

[ArdWrknTrk]

I see David's sig in Chrome....

Check to see if the regulator is getting proper 'sense' voltage.

If the regulator doesn't know the battery is charged (or the system voltage is 14.7) it will tell the alternator to keep charging.

[PetesPonies]

Yes, an un-regulated alternator will create 18 to 24 volts or so. So if you saw 18, then it was not regulating the alternator . . .which means turning it on and off. It was being left on. So if something can leave it on . then it seems plausible the something can also leave it off :)  which is what happens when there is no charging. An alternator is constantly being turned on and off, how much on determines how much power is generated, which is to supply how much power is being used. So it varies depending on your load. Now . .can an electronic part malfunction is both ways? Not likely. A mechanical regulator, absolutely, but you don't have one of those. So after all this verbiage . . .  I think I would still start running down connections.

[ArdWrknTrk]

David, does "factory ac, no tach" in your signature mean you have an idiot light dash with no ammeter?

There are two ways to wire a 1G alternator depending on how the dash is optioned.
I have pointed this out in a number of 3G swap threads on FTE.

If the alternator and regulator connections are not correct for the way the truck harness is set up you will have the problems you do.
'Heavy Duty' doesn't mean anything to me.
But the order of wires in the regulator plug matters.

[85lebaront2]

Jim, on the 1980-86 dash, the tach was an option and sat in a small center area of the cluster, with no tach there was a blanking plate installed where it would mount.

[ArdWrknTrk]

This doesn't tell me if it's ammeter or idiot light.

[jdavidsmi]

The Alternator is 1G, a couple of months old, new, not a rebuild. I have the gauges on my dash, but the dash does not have a tach, just the blank spot.
When I first got the truck I added a stand alone volt meter, everything I read said not to trust the amp meter gauge.
The term "heavy duty" for the voltage regulator is what the guy at NAPA call it. its NAPA # is ECH VR440. which is a Echlin.

David

[PetesPonies]

So you have an integral regulator . . . what needs to be checked are the connections to the regulator..

[ArdWrknTrk]

No, he has a 1G with an external regulator.

[PetesPonies]

OK stock alternator, then you do  this very basic test. Unplug thew regulator and jump the F and A terminals together, at the connector. Check the battery voltage with a voltmeter. It should be very high. If it is not, you have an alternator problem or a wiring problem feeding the alternator.If it does jump high, but when plugged back in the voltage at the battery returns to an unacceptable level, you have a bad regulator or bad wiring feeding it. Not fun stuff, but not too difficult. This simple test will clarify the problem.

[jdavidsmi]

Pete, thanks for the information but I do have a couple of questions about the test. after I jump A & F do I start the truck? and checking the battery voltage is between the pos and neg post on the battery, correct?

David

[PetesPonies]

after I jump A & F do I start the truck?  . . . . you do if you want to get a charging reading  :)

And yes checking battery voltage right at the battery terminals.

[jdavidsmi]

thanks

[ArdWrknTrk]

So your truck *does* have an ammeter?

I'll post the wiring diagram and troubleshooting.
Better yet, take advantage of the tremendous resource Gary provides and look for yourself at the EVTM charge circuit he has here on his website.

Click the hamburger at the upper left of this page.
Click EVTM.
Choose a year.
Click charge and power distribution.
Choose with ammeter.

There you will find all the factory troubleshooting,  simplified wiring diagrams, and illustrations.

I'm willing to bet you have a wire mis-connected, for the system you have.

[PetesPonies]

No test yet?

[jdavidsmi]

Completed, the test voltage was around 17.10, moving up down. About the same as when the regulator was plugged in. Looks like a another bad regulator.

I have rechecked the wiring to the alternator and it was correct. The wire from the bat terminal on the alternator, branches at two locations between the alternator and the starter relay, this wire pass the second branch, near the starter relay got very hot.

But everything has to be on hold for a week, We are heading up to Mass., for a family member's funereal.