Over charging?

[Valiant273]

Hi Guys,
65 Valiant 273 engine, electronic ignition
Had an issue with ballast blowing a few days ago. Replaced it and no change, noticed crack on top of coil and thought aha that's it. Nope, replaced coil no change. Next changed the ICM and that fixed it.

The odd thing is all of a sudden it seems to be charging way too high. My voltmeter, if correct shows almost 19 Volts under moderate throttle and about 16 on idle. Does not look good to me.
Even the original gauge in car shows needle way higher off just above middle then it ever was.

Thoughts?

 

[plumkrazee70]

Check the voltage at the battery with a volt meter. My guess is your Voltage regulator needs replaced or isn't grounded properly. I'm sure Del (67dart273) will chime in with some tests.

 

[mod5v]

If the diodes in the alternator short the alternator will do that and if you run it very long will cook your battery and who know what else.

 

[67Dart273]

This is not "diodes in the alternator"

What do you have for an alternator / regulator? Is this the old style 60X---69? or the 70/ later style?

If this is the old style, merely unplug the green field wire. This will tell you that the VR is what is controlling the voltage. Charging should immediately stop, and battery voltage should drop some.

If that happens, remove the VR, scrape around the bolt holes and remount using star lock washers. The VR MUST BE grounded.

If this does not fix the problem, next, check for "voltage drop" in the harness. To do this, hook everything up "normal" and turn the key to "run" with engine stopped. Stick your meter on the VR "IGN" terminal...this is the "push on" terminal. Put your other meter probe on the battery POS post. You are hoping for a very very low reading, the lower the better. If this reading is more than about .3V (3/10 of one volt) you have harness drop. POST BACK with that reading.

If the reading is only about 1V, it will overcharge BUT NOT give you the trouble you have.

If the reading is not much over 1V, and we hope less, replace the regulator.