I had my alternator rebuilt. Now I am having a problem getting it to charge at idle, I get 14.5 volts at 1500 rpm, but as soon as I release the throttle it drops down to battery voltage, I've returned the alternator once already. He checked it again, replaced the regulator and said it's putting out full voltage, but on the car, it's doing exactly as I mentioned before, no voltage at idle, full voltage when revving the engine. Could this be a PCM issue?
Check the belt and belt tensioner for the correct tension. Take a look at the connections at the back of the alternator, especially the B+ connector. On early models the indicator light on the dashboard should come on when the ignition key is in the On position, otherwise, you'll have problems at idle. There could also be a problem in the charging circuit, a loose, corroded or damaged wire can also prevent full voltage at low rpm. Take a look at the grounds and the output wiring to the battery. You may need the diagram for this. These other posts may help:
Updated on November 17, 2019
By Dan Ferrell