Overcharging

[Mopars & Missiles]

Latest on my voltage regulation problem,

I finally got back to the garage today and did some more troubleshooting to isolate the unwanted voltage drop in the wiring to the voltage regulator. I had suspected it would turn out to be excess resistance in the Ignition Switch contacts. I was wrong! Turns out the problem is in the Ammeter in the instrument cluster. There is a little over 3 ohms of resistance in the ammeter (3.2 ohms) which is causing the voltage drop. The ignition switch itself only measured 0.3 or 0.4 ohms, so it is insignificant compared to the Ammeter loss. Also, when cycling the ignition switch a couple of times to "wipe" the contacts, the reading will then go to 0.0 ohms. So I need to pull the ammeter now and see what's going on in there.

Ratroaster, not saying this is what is causing your problem too, but wanted to let you know what I found just in case it can help you or someone else that is having a similar problem.

 

[GearAddict]

Update #4 I took the alternator to a reputable alternator shop ( 40 miles one way )and it tested good. I've checked the ground from the battery ground cable to the VR housing and appears good. Although I'm going to add a ground from the
block straight to the VR. I guess I could try one another new VR and see what happens. Also considering a ignition
switch replacement as I have no idea of the age of one in the car. Assuming all this comes to naught, I'm going have to
obtain some expertise in chasing voltage drops. Mopars & Missles gave me a good start. I really dislike auto electric.
Thanks again for all the help.

I feel your pain man.. I had the same problem of overcharging, bought 3 different types of voltage regulators, chased wiring, ect.. for about 2 weeks. Here's what I can tell you I learned in no specific order.

1. Ensure you have good ground connection on the VR body.. measured in ohms from VR body to neg batt terminal... should be less than 0.3 Ohms (0 to 0.1 is achievable).

2. Measure the resistance from the batter pos to the hot wire connecting to the VR (sounds like you did).. it's worth chasing through the connectors and using some contact cleaner, sandpaper on the contact terminals and if needed, replace, re-crimp, re-solder.. try to get the resistance down to under .5 ohms if possible.

3. If you are not a purist.. I recommend going to a ford style regulator that allows for remote voltage sensing... this REALLY solved my problem and is better engineered than MaMopar (sacriledge I know, but we all know that electrical was one of Chrysler's week points). Common problem is that the mopar regulator is measuring voltage through a pretty long wiring path, with many connectors involved.. this can amplify the voltage drop, which means that the alternator is adjusting voltage up based on the lowest voltage.. this is not really the best, for exactly the issue you are trying to solve.

The difference for the ford/GM style is they allow to sample the voltage from a more centrally located point in the harness (I have a power stud mounted on the firewall, that is 5 ft from Batt, 6 ft from VR/Alt, 5 ft from dash...and so on).. this means that the VR is reading a "mid-point" voltage and adjusting to that rather than adjusting for the lowest point in the system.. Works really nice, wires in easy to current circuit, just add one additional wire run to someplace for that mid-point voltage.. presto! runs- steady right at 13.5-13.8 volts, which is where you really want to be.

If you are interested in how to do this, search on my threads in electrical section on the site to read through my pain an solution or just ask and I will try to provide some help.. I'm not saying the mopar regulator won't work.. I just found this much easier and stronger solution.

 

[rcb]

Ammeters are often trouble spots. they've caused more than a few dash fires. Only time I really had problems was on a powerwagon. Though it caused me dash to smoke, I was able to get to it before it caught fire.

 

[Ratroaster]

Ok guys, I think I've solved the problem. Apparently the way I had the electric fuel
pump wired into the ignition circuit was causing the voltage drop.
I finally decided to get a 30 amp, 4 prong relay and wire the pump through that.
In trying to keep the under hood area somewhat neat I installed the relay under
dash and took the batt. power from the cigarette lighter circuit ( 14 amp fused ).
Now I'm charging 14.8 volts at the batt. and the voltmeter so I am hopeful that
the problem is behind me.
Thank you all for your help. There were some great suggestions offered.