Alternator Pulsing
Even though you're using a relay to power the regulator, actually check the regulator hot lead AND ground
Turn your ignition to "run" but engine not running. Stick one probe of your meter on the battery POS post, and the other on the regulator IGN terminal. You are hoping for a very low voltage, the lower the better, and not above .2V (2 tenths of a volt)
Then check the ground path. To do that, start the engine, run at "low to medium cruise" RPM, and check both with loads off and with lights, heater, etc on
This time, stick one probe on the battery NEG terminal, and the other directly onto the regulator mounting flange. Be sure to stab through any rust, dirt, paint, chrome, etc.
Once again, you are looking for a very low voltage the lower the better
Is this an old style electro--mechanical type or is it a replacement solid state? You can tell by looking at the bottom of the regulator. If there are two fairly heavy resistors under there, it's an electro/ mechanical type, and may be suspect
There is also some chance that you have an odd ground loop. You might try a heavier ground. If your battery is front mount, the main ground should already be to the block. You can add a very heavy ground by getting a 1 ft starter cable (ring to ring) and bolting it to the unused alternator mount holes on the rear of the driver side head. Ground the other end to the firewall, either big heavy bolt through firewall, or to such bolts as the master cylinder mounting studs.
Electro--mechanical, notice resistors
Underside of a couple of solid state replacements, no resistors
Even though you're using a relay to power the regulator, actually check the regulator hot lead AND ground
Turn your ignition to "run" but engine not running. Stick one probe of your meter on the battery POS post, and the other on the regulator IGN terminal. You are hoping for a very low voltage, the lower the better, and not above .2V (2 tenths of a volt)
Then check the ground path. To do that, start the engine, run at "low to medium cruise" RPM, and check both with loads off and with lights, heater, etc on
This time, stick one probe on the battery NEG terminal, and the other directly onto the regulator mounting flange. Be sure to stab through any rust, dirt, paint, chrome, etc.
Once again, you are looking for a very low voltage the lower the better
Is this an old style electro--mechanical type or is it a replacement solid state? You can tell by looking at the bottom of the regulator. If there are two fairly heavy resistors under there, it's an electro/ mechanical type, and may be suspect
There is also some chance that you have an odd ground loop. You might try a heavier ground. If your battery is front mount, the main ground should already be to the block. You can add a very heavy ground by getting a 1 ft starter cable (ring to ring) and bolting it to the unused alternator mount holes on the rear of the driver side head. Ground the other end to the firewall, either big heavy bolt through firewall, or to such bolts as the master cylinder mounting studs.
Electro--mechanical, notice resistors
Underside of a couple of solid state replacements, no resistors
