Bad alternator?

robjkc said
Well, my alternator and battery both checked out OK. I raised my idle a little to keep it from dying while in Drive. To keep it from dying I have it idling at about 650-700 rpm while in Drive, which means it idles at around 800 while in Neutral.

I hooked up a voltmeter to the battery and while idling in Neutral the voltage reads around 14.3 volts (with lights on). When I idle in Drive the voltmeter reads about 13 volts on the battery and my ammeter goes toward the "D" (Discharging). Once I switch it back to Neutral the voltage slowly goes back to 14.3 volts.

Is this drop in voltage while at the lower rpm normal or do I have an issue with the voltage regulator or something else? Thanks!

Yes, it is normal for a little alternator to go to a slight discharge o the gauge. BUT, as you just told us at idle it is still @ 13v. There is nothing wrong with 13v. when you consider the battery voltage is normally 12.5v. What happens when you increase the engine speed is the alternator is capable of putting out more amps. and there for charging the battery to the desired 14.2v. the regulator is designed to keep it at. These old cars have small alternators, usually around 30 to 40 amps. Plenty for a plane Jane car with no A/C or other options. It sounds fine to me. The dying is another problem! Carb. issue?