[Bill Hanlon]

So you installed an alternator that was designed to be 1 wire.

I'd start where John Wallace suggested. Check the alternator output voltage a minute or so after starting.

It would also be interesting to know how many amps the alternator is putting out a minute or so after starting. I keep an old under-dash ammeter with about 2 foot long wires with alligator clips on the end as a troubleshooting tool. Disconnect the "one wire", clip one wire of the ammeter to the "one wire" and the other ammeter wire to the stud on the alternator. Start the car leaving all electrical thingies turned off, goose the throttle once to get the alternator charging and read amps after a minute. Should be less that 10 amps, probably less that 5.