Overcharging....

[wesmc]

I have a very early 1970 240z barn find.  Clean little car and I replaced starter, alternator, battery, ect just because she was parked for so long.  Wiring in the engine bay looks like new.  Car is overcharging the bejesus out of the battery, so I replaced the voltage regulator.  Still overcharging.

 

Have 12v on the exciter wire.  I checked the grounds and all seem to be fine.  I have continuity between the ground wire pin on the regulator harness and between the body of the alternator and the negative post on the battery.  Amp meter on the dash is working and is buried on the high end when the car is revved up.  The output wire off the alternator gets HOT.  Verified high output with DVOM.

 

Any thoughts on why she is still overcharging  with a new regulator?

[NewZed]

One of your connections may be missing.  Check the wiring diagram for 72 and you'll see the four connections between alt. and regulator.  F, A, E, N.  Engine Electrical chapter > Charging Circuit.

 

The letters are usually cast in to the back of the alternator and may be marked on the regulator also. 

 

http://www.nicoclub.com/FSM/240z/

[beermanpete]

The most likely wiring problem that would cause this is the white wire going into the regulator might not be getting 12 volts from the alternator output/battery as it should. Also, the new regulator could be bad.

[wesmc]

Thanks for the diagram Zed, will make things tons easier. 

 

Beerman, I will check that wire, I have only checked the exciter.  I'll also look for a test procedure for the regulator.  Thanks