first off 70 chally 440-6pak 4spd car did tons of research tried everything except replacing the ign switch.i even did the relay to battery to VL that worked for a while now back to creeping up to 16-17volts.ammeter is bypassed now also..... im at a loss can anybody give any insight????

what is a VL?

there are only a few main reasons for over charging and each one has a test.

Sensing voltage at the vr, what is it? IF it is not the same as battery voltage, you have a drop somewhere and it will cause you to over charge.

Bad VR, those can be tested as well. But usually I just rule it in or out based on the other tests.

Internal short to the ALT. Someone posted about this just recently accidently damaging the alt when putting in a screw caused it to over charge.

Intermittent connections to the VR or to the ALT may make it think there is a different voltage than there actually is. BUt again you check voltage readings at each of the fields for the ALT and compare the readings back to make sure they are the same. Either at the VR or the bulkhead or the sensing line as they tap off the same place.

Bad ground is harder, but that I just add a direct ground to be sure.

One of these things is the issue.
Maybe I forgot one but Rapid Robert or someone else will be along to give you other tests.

VL is voltage limiter i meant to say regulator just had it on my mind since i just changed it(behind the dash to limit voltage to gauges).VR is good tried 3 tested on a working car to confirm.tried good workingt alt...added direct ground also........i will do more testing let you know thx.

Did you change the battery? Check cables for voltage drop?

pull the blue/green field wire connectors off of the alt field terminals and ohm the male terminals (the alt internal field circuit). then ohm each one to the alt case. visual on the brushes/brush holders for any (improper) continuity to alt case that you can see. pull the brushes/brush holders & visual for anything that dont look right such as something touching that should not be touching & when replacing them they wear at an angle so restore that clocking. You might also sub in another alt for a quick test (I have a dozen I am tripping over) or take it in to your parts house & have them spin it. borrow another good/fully charged battery & sub it in for a quick test. pull all blue/green field wires/connectors off & with jumper wires with small alligator clips (fab em up they will come in handy in the future) jump 12V to one field terminal and 12V to the top nub terminal in the reg triangle with it facing up like a pyramid as some are not and run a jumper from the side reg nub terminal to the other alt field terminal (no voltage,just connect those 2 to each other, you are duplicating the green wire alt to reg field circuit) & run it at a fast idle & see what you get for voltage at the alt "batt" stud terminal and at the battery posts. Only do each running test for ~4 seconds just long enough to read your meter as this high of pressure is extremely damaging to the system & have the lights/radio etc OFF. I'd do the battery first (easy to do) then the alt then the jumpers. Holler back when you can. WAG-the alt (part time loose or dead shorted connection). EDIT confirm there is no draw with everything shut off (pull a batt cable off of its post at midnight & should be no spark (assuming no clock or LED indicator light on a stereo face etc that is on all the time) & this is with eng OFF, all lights everything off (no spark=no draw)

Yes Robert tried a good working alt, VR and battery so thats not the prob.i will check for draw and report back.thx

Did you look at the main connection thru the bulkhead ?

YES one of the first on the checklist...........

Like Andy mentioned, the first test I would do is to measure the voltage between the battery positive terminal, and the blue wire at the alternator while it's running.

That is, put your positive lead on the battery +, and your negative lead on the blue wire. Try to find a safe way to probe the blue wire at the alternator.

Ideally, this will be 0v or close to it. If it's any higher, the battery will overcharge by that amount.

If it is above 0v (I'm guessing you'll see 2-2.5v) you have a voltage drop through the harness before it gets to the blue wire.

Do you have GOOD ground straps (wires) from the engine to the vehicle body?
Ron

OK ill try that tm............if it does have a drop how do i go about finding it??

YES

voltage drop measurements.

Two ways to do it.

Method one.

Measure voltage from one end of wire to ground, write down reading.
Measure voltage from other end of wire to ground, write down reading.
The difference, if any, is the voltage drop.

Method two.

Measure voltage from one end of wire to other end of wire. The reading you get is the voltage drop across that wire.

For example, with the key in run you can measure from the battery post + to the switched 12V wire at the VR or alternator, the reading on the meter will show how much drop there is in the entire circuit, connections, wiring, switches, etc. You can measure back from one end to the other to figure the section/part with the issue.

Remember, the closer to zero you get for a voltage drop measurement the better, .2V or so is probably ok, more than that and I'd be cleaning things up.

supercuda covered it pretty well.

The sense line (blue wire) goes from the battery, through the bulkhead (twice), through the ignition switch plug (twice), through the ignition switch itself, and maybe another connection or two along the way. Any or all of those can be less than ideal.

My solution was to mount a relay under the hood, have the old blue wire trigger it, and run a new wire through the relay to the alternator/ignition subsystem.

No more overcharging for me.

Edit: if you do find a large voltage drop, you can temporarily install a jumper from the battery + to the blue wire at the alternator to bypass all of the voltage drops. That should immediately bring your charging voltage back down. Note that it will no longer turn off with the key while this jumper is in place

One other thing you have to remember.

All electrical circuit require a supply and a return.

Both the supply and the return can have voltage drop issues.

In cars the return isn't as obvious as the supply, because generally the return is the body, or the block.

You must have a good ground to both the body and the block from the battery and the alternator. You can use the voltage drop method to test that connection as well.

if the hard components (batt/reg/alt) are good then it has to be a voltage drop issue on the supply side or the ground side. Now if there was an unwanted draw (& I'm thinking not from your clue) that ran the batt down then it would charge high or even peg (full field) till it replenished the battery & you'd see that on immediate startup then it'd return to normal after awhile. the puzzler (the clue) to me is it worked for awhile then the voltage started to creep back up as something dont make sense on that symptom (the slowly creeping upward). Stay on it we need to know. I'm still thinking batt or alt or loose/part time connection somewhere but I am speculating

My solution was to mount a relay under the hood, have the old blue wire trigger it, and run a new wire through the relay to the alternator/ignition subsystem.

No more overcharging for me.

i did this and it solved it for about a week......now overcharging again with relay in place.....why?????

what was the power to the relay coming from?
it says the battery in your original post.

What type of connector and wiring did you use? intermittent connections cause this too.

What type of ground did you wire to the vr? where is it grounded to?

Did you check your wiring to the alt? it also could be bad/poor connection. check your voltage drop there. Both lines to the fields.

1. yes direct to + batt terminal
2.used butt connectors same gauge wiring
3.put a ground strap right from vr to engine block(cylinder head)
4.even replaced the one field wire(green)checked connections(good) i will look for voltage drop soon.............thx

thought it was a 70.
do you have a dual field alt or single field?