Charging system over voltage!?!

[wsutard]

I need some help diagnosing a charging system issue. Yesterday on my drive home I noticed that my volt gauge was reading +16v on idle and pegged at 18v on RPM. I tested at the battery and confirmed that at idle I was seeing over 16v of current. I also happened to notice that there was what looked like water on the top of my battery with no apparent source which leads me to believe it was leaking out the battery caps.

I also tested the voltage at the alternator and it was also showing +16v at idle.

How should I go about diagnosing what is wrong?

 

[Billccm]

If the field of the alternator is shorted to ground, or if the regulator believes voltage is low, you will will have the overvoltage condition.

You are probably boiling the battery at 18V? Maybe? Max spec is 15.2V, and 16V is not too far off. I assume you have a digital voltmeter across the battery and measure 16V?

 

[wsutard]

If the field of the alternator is shorted to ground, or if the regulator believes voltage is low, you will will have the overvoltage condition.

You are probably boiling the battery at 18V? Maybe? Max spec is 15.2V, and 16V is not too far off. I assume you have a digital voltmeter across the battery and measure 16V?

Yes on the voltmeter. So you are saying I should try to track down the wires from the alternator and see if I am shorting any of them?

 

[wsutard]

Crap. Looks like I caught this in time. In the pics you will see scorching on the butt connector. You will also see that the black wire next to the red wire has started to melt it's coating and is now sticking to the red wire. Looks worse under the dash.

I still don't see why this is happening but looks like I finally need to rewire this thing.

 

[furyus]

You need to check all connections. Especially grounds,adding some won't hurt. Check all connections. Especially the bulkhead connector. Repair anything not up to standards. I had a battery explode, blowing acid all over the hood. Dripped on my new jean jacket as I looked underhood. Be careful.

 

[wsutard]

I am going to rewire it all. The wiring is original and cracking everywhere. No telling where the real issue is.

Now my question is, do I make my own wires or do I order a new wiring harness from Year One? I have the proper connectors if I want to do it myself. Just need to find some wire local.

 

[toolmanmike]

Make sure your regulator is grounded to the firewall. A loose mounting screw is enough to cause issues.

 

[moes]

to start I would cleanup the bulkhead connectors and then add some dielectric grease to them to stop the moisture from getting at them. The grease will help stop future corrosion while allowing the electricity to make contact through it. Bulbs, under-hood connections, spark plug boots and any other connector that may get wet or corrode are great candidates for dielectric grease.

 

[wsutard]

Make sure your regulator is grounded to the firewall. A loose mounting screw is enough to cause issues.

The regulator looks normal. Not missing any screws or connections.

 

[747mopar]

I am going to rewire it all. The wiring is original and cracking everywhere. No telling where the real issue is.

Now my question is, do I make my own wires or do I order a new wiring harness from Year One? I have the proper connectors if I want to do it myself. Just need to find some wire local.

Depends on how fast, original or cheap you want it done? Buying a factory correct harness by far is the simplest, quickest solution... buying a universal aftermarket harness is a good upgrade and cheaper but time consuming... Replacing the wires yourself is the cheapest option but also time consuming?

I like upgrade.

 

[wsutard]

Well, considering I want to upsize the alternator wire as well as other wires and I have an MSD box, I should probably do my own wiring harness.

Ugh, this isnt what I wanted to do right now.

 

[Billccm]

Keep in mind your over heated wires maybe just a symptom of the problem, and not the cause.

I think you should start with the alternator field wire and trace, visual inspect, and detect with an ohmmeter (battery disconnected) any low resistance to ground. I would not replace any harness until you discover and prove the original cause.

Although not the very best test, you could unplug the alternator, connect the battery, and with the ignition to ON look for large current paths (discharge). Thinking out loud shorts to ground should blow a fuse, so if nothing is direct wired your shorting situation should be good.

Auto stores also can bench test an alternator; sometimes it is a good test, sometimes it does not show much. At least it can build confidence that the alternator is good, etc.

 

[wsutard]

I will do the tests you suggest.

I am still going to replace the harness. I keep flip flopping but I think I am going to go with the M&H on Yearone. However, I cant decide which one I should select, the points setup or the modified electrical ignition/alternator setup. I have the firewall based voltage regulator, and an MSD 6al. Yearone says to go with the points harness if you have an aftermarket ignition system but I'm not sure if that still comes with the voltage regulator connection. The pictures provide no help as they are the same. Adding complexity is the fact my b body has a 340...I dont think this will actually mater in the long run.

Modified Electrical

Points

 

[oldbee]

You could have a shorted internally battery also making the alternator overcharge, but it's unlikely; more often bad regulator or alternator.

 

[multimopes]

I had a similar problem with a 70 Challenger 40 some years back. I bought it used and the guy I bought it from said he went through 3 or 4 voltage regulators since he bought it new. Some were replaced by the dealership. I think this was the first year for the solid state regulator. Anyway, after about a month, it started wildly overcharging, maxing out the gauge and later discharging, (all over the place intermittently). I spoke to someone about it and they mentioned bad grounding of the regulator. I removed it and noted the factory black paint covering the whole unit and the factory painted firewall. At this guys suggestion, I sanded the both front and back of the regulator at the bolt tabs AND the firewall where it bolted up and added a dab of grease between mounting points. Reconnected and fired up the car and it performed perfectly for the next 100,000 miles until I sold it! I hope your trouble shooting goes well. It probably isn't as simple as mine was. Good luck!

 

[Lionized]

I will do the tests you suggest.

I am still going to replace the harness. I keep flip flopping but I think I am going to go with the M&H on Yearone. However, I cant decide which one I should select, the points setup or the modified electrical ignition/alternator setup. I have the firewall based voltage regulator, and an MSD 6al. Yearone says to go with the points harness if you have an aftermarket ignition system but I'm not sure if that still comes with the voltage regulator connection. The pictures provide no help as they are the same. Adding complexity is the fact my b body has a 340...I dont think this will actually mater in the long run.

Modified Electrical

Points

You'll want the modified electrical. Plug and play.

 

[HT413]

If the wires are that bad, just replace it all. If they look ok, then just clean your connections.

If your gonna clean, use an eye dropper to apply a mix of salt and vinegar onto any suspect copper connections. It deox's copper in seconds, leaving bright virgin copper. Then rinse with water to neutralize the vinegar and flush the salt, then some compressed air and maybe some wd40 to displace the water and finish with dielectric grease to protect it all.

 

[Ranger16]

Unless I missed it, I did not see what kind of voltage regulator you have. I had a similar problem about 3 years ago. I had the OEM factory regulator with spring loaded contacts. I removed it and replaced it with a Wells VR706. Never had a problem since. It sits at about 14.5v with very little variance (with a 55 amp alternator).

 

[oldbee]

AND I'll bet that 'ranger' cleaned up his grd. connection. Grounds,grounds,etc. you can't ever forget; I spent 30+ working on semi's and grounds were always a problem and would drive ya crazy at times.

 

[Wietse]

I had the same issues for some time, 15-16 volt at idle and over 20 Volt during higher revs.
Turned out to be just a bad voltage regulator, installed a new one and all was ok.

That the connections turn so hot that it melts the insulation is most likely caused by the fact these type connectors are not made to handle these type of loads.
Best is to solder them together to make a solid connection without the chance of creating a bottle neck. (specially if you want to up the Amp rating of your alternator you cannot have these type of connectors)