[GTO Noob]

George, (or anybody who wants to chime in)

I have an issue with my 69 GTO 400 with AC.

I recently got it back on the road after stripping the entire front end down to bare metal and rebuilding the engine. I also replaced all of the wiring harnesses including ground straps and ext regulator. I just recently replaced both battery cables and the battery after my car almost burnt to the ground due to my + bat cable melting against the block.

My issue was and still is that my regulator makes noise and sometimes pulses. I can hear it whine through the firewall of click as the voltage jumps bewteen 14-15 volts. When I start the car the voltage will sit at about 13 volts and then rise quickly to anywhere from 15-16volts before is jumps back down to 14 and then pulses. I have checked the voltage from my alternator and it runs between 14-14.4 volts.

My question is do you think I have a bad regulator even though it's brand new or is there a problem with my alt since it's output is varying as well? Or is it something else?

[george kujanski]

Your charging system is what's called a feedback control system. The regulator drives the alt, then measures the output volatge and readjusts the control (field) to keep the output at a set value. A prob with the reg will casue the alt to act funny, which will make the reg act funny, etc.

Since your regulator is new, a possible problem is that the regulator body has a poor ground to the firewall, or the firewall is not connected well to the battery negative. The reg measures the voltage between it's term #3 and ground so a bad ground will cause a sensing prob.

Other possible probs could be a bad stator winding causing a low voltage on regt term 2.

Also check for poor connections on the wiring between the alt and reg.

Most likely it's a ground issue. If it's still a problem, a simple permanent solution is to replace the alt/reg with a 10SI from a '73 and up GM. It has a internal reg and the install is simple.

George

[GTO Noob]

George,

You should know that the first thing that I checked was the ground. After all that's what I preach in here all the time

I took a jumper wire with alligator clips on either end and clipped one side to my regulator foot and the other end to the brand new ground strap going from my engine block to my firewall. It made no difference.


I really don't want to go to an internal regulator alt. one because I just installed brand new wiring harnesses and two becuase I have a chrome altenator body on order for an ext reg alt. I doubt that it's a wiring problem between the alt and reg because as I said it's all new wiring. So if you think it's a stator issue that would mean I probably need to replace my alt. Right?

[BILTIT]

If its a stator problem, you can just replace the stator. You could take the alt. down to the local alt/starter shop and have them check it out, they should be able to check the stator.

You should also be able to test the stator with a multimeter. Check for any resistance between stator and ground (should be open/infinite resistance). I think each stator winding should be open/infinite resistance in relation to the adjacent ones (they will need to be disconnected for this test).

Thats about my limit, its been years since ive had an alternator apart and done any testing so i am going by memory.

George should be able to add to this and correct anything i have goofed.

[Lemans64]

Careful when u say It's a new harness and should be good, Not alway, my 64 harness from m&h wiring harnesses ahd terminal put in the wrong location. I just happen to check it before installing and found 1 wire in the wrong spot, wasn't a big deal at the time BUT could have been a big deal if I tried to start engine on this harness.