1980 2.3 non-turbo charging

I have a non-turbo 80 that has a 2 wire connection to the alternator. Parts store says I should have a 3rd wire. I had 79-80 2.3's when I was younger and don't remember any more than a 2 wire hook-up. Alternator tests as good, but won't start or run w/o a jump or boost. It will also die at idle after 10 to 15 minutes... any suggestions?

thanks

do you have an external voltage regulator??

if so, let the parts store know this, the 3-wire is with the internal regulator.

have you had the alt and the regulator tested yet??

Ah ha, yes it does. I had the alternator checked, it was ok. When I bought the car the guy I bought it from said he had recently replaced the regulator. I'll try that next.

Thanks