Hello, I'm buttoning up a carb swap on my 1989 firebird, so I figure it is time to find out if I have my alternator wired properly.
1989 firebird 305 (former) TBI
ECM and factory engine wiring harness is gone.

I have the main alternator charging wire prom the post on the alt to the battery. It is fused.
I also have the 2 pin plug on the back of the alt. The thicker red wire goes to the positive terminal on the starter solenoid. The tan/white wire went to the ecm, and was connected to the a/c relay. I obviously don't have an ecm anymore, and I have no a/c, so that tan/white wire is just hanging out. I have read about a brown/white wire that is connected to key on power and a resistor/idiot light, is that how I should wire my tan/white wire?

 

Dang, I was hoping I would get some input. I'll have to poke around.

 

why did you take the engine wiring harness out?

 

I did a carb swap, and rather than leave in the TBI harness when I no longer needed it, I just ran new wires to the few things I was keeping (oil pressure switch, ignition power and tach, fuel pump wires, wipers). I'm trying to tidy the car up, and I didn't want to have an anaconda of unused TBI wires tucked into every crevice of the engine compartment. The TBI on this car was hashed, and the wiring looked like it was installed by Edward scissorhands. It ran poorly, and it runs better with a carb.

The good news is, I figured out how to hook up the alternator. The small tan/white wire to a positive source with a 194 light bulb in the circuit seems to do the trick. Holds 14.4 volts consistently.

 

[QUOTE=Firebirdwade;6259229

The good news is, I figured out how to hook up the alternator. The small tan/white wire to a positive source with a 194 light bulb in the circuit seems to do the trick. Holds 14.4 volts consistently.[/QUOTE]

that is how these have been wired up on the alternator .. fused feed to the dash bulb then to the alternator brown sense wire.
the carb choke has a relay that when the alternator is working the relay supplies 12 volts to the choke heater. the small current flow thru the fused bulb dash light goes to the choke relay coil that current flow then creates the choke power to turn on .

so key on engine off no power to choke .

 

That's good to know, thanks!