I just checked my battery with a volt meter with the 66 coupe turned off and it was 12.45 volts. I then cranked it up and checked while running and it wasd 12.25 volts. Does that mean it is not getting a charge? The alternator and wiring harness is brand new. Could a bad voltage regulator cause this? I had one bad on a 65 and it caused the battery to get too much charge.

What should I check next? Bench test the alternator? Or is there a way to check the voltage regulator?

Thanks!!

Warren

 

Yeah that means its not charging.

maybe the previous owner hooked the wires up wrong to the alt.
The alt could be bad
the regulator could be bad.

What I would do Is look to see which color is going to which post on the alternator then post that here. Then once we get that figured out (are the colors actually going to the right place) Then we gotta figure out if that color representation is actually true. What I mean by this is for example is lets say red is +12v is it really +12v or does it run to ground.

Its a safe bet to assume something is messed up with the way its wired.

-Gun

 

Voltage is to low, you are running off the battery. Quick old school test is while the car is running pull the positive off the battery. Car dies alt is not charging.

 

I checked the wires and here is what I have.

Alternator:

Top Terminal - red plastic with yellow wire and black w/yellow stripe wire
Middle Terminal - white plastic with white wire
Bottom Terminal - No plastic and black w/red stripe

Voltage Regulator:

1 - White w/black stripe, comes from instrument panel
2 - Yellow wire from alternator I think - also has a condensor connected to it?
3 - Green w/red stripe wire
4 - Wite wire from alternator

The wiring harnes is the Painless harness someone else just put in.

Couple things I noticed:

The Black/red wire from alternator goes to the voltage regulator and is grounded over there instead of going to the negative battery terminal.

Should the Yellow wire on top post of alternator have power when the key is turned on? Or is that power generated and sent to the voltage regulator first?

Also, with the car running at idle, will the battery show a higher charge if charging or only if the rpm is higher? I read it has to be 1500 rpm before the battery shows it is being charged.

Thanks!

Warren

 

I just checked with a meter between the negative on the battery and the ground wire (black/red) on the alternator post and it's good. So I have a good ground there.

If all of the wiring is good, should I have the alternator bench tested and if good, replace the voltage regulator? Isn't there a test I can do by bypassing the voltage regulator to check if the alternator is charging?

Warren

 

I pulled the alternator and had it bench tested and came out fine. I then bought a new voltage regulator and replaced it but same results. So that was fine. I checked where all of the connections go on the alternator and voltage regulator and they are correct. But it is still not charging.

I can read the 12v on the post on the alternator with the battery connector. Where else can i check for voltage to see if it is outputting it to the battery? Does the charge to the batter come back from that same post on the alternator? Any suggestions on what to check next?

Thanks!

Warren

 

What kind of voltage regulator did you get? The economy versions sold at most parts stores are pieces of crap. A quality Borg Warner (CSK/O'Reilly's) or Echlin (Napa) unit would be the only way I'd go. If you paid $15 for it, you can bet it's an inferior chinese part.

 

Im still betting the wiring harness is installed incorrectly.

But I cant tell you which colors do what.

I was hoping someone could tell you what to expect when you test each color with the ignition on.

Here is a charging diagram

http://www.hammar.dyndns.org/~djhamm...66/66ignit.jpg

1) Connections are: Ground (black and red), stator maybe (white), unknown (black yellow)

Look this over it might help

-Gun

 

Thanks Gun Jam, I had printed the same diagram and a friend and I went through it all for 3 hours yesterday afternoon and everything is hooked up right. Still the volts at the battery was 12.3 when running it. We even added an extra ground to it to make sure it is hooked up right. There was a new voltage regulator on there and I even replaced it and same result.

Advance Auto Parts did a bench test on the alternator and showed good. A friend said he did it at one store and showed good but them another showed it bad. So as a last resourt I'm going to have it tested at Autozone next. If it shows good there, I have no choice but to take the car to an auto shop which I REALLY hate to do!

Warren

 

I know the diagram doesnt tell in words what each wire does (thats kinda the problem) but I suppose that a logical guess could be made by following each wire and seeing where it goes.

Im surprised no one else knows either.

Do you think the wires that go to a specific post on the alternator are actually carrying the right signal. (practical example) There is a ground wire the goes to the alt and to the regulator. Is that wire actually grounded? Does it run to the regulator as well??

And this has to be done for each of the wires.

What Im really saying is. The previous owner slapped a new harness in there knowing full well he was gonna sell it. It worked well enough to get it to start he didnt care that it wasnt charging (or didnt know) so we cant assume that just because each wire with the right color is going to the right place it should work. He might have switched or crossed some colors down the line...Are they even the same colors as indicated by the diagram?

-Gun