I bought a 108-amp alternator for a 85 camaro with fuel injection, A/C, power everything, instead of the factory 50something amp alternator that came with my camaro. It's an 84 power nothing and non-A/C car. This alternator won't charge and i've heard comments about a 10ohm resistance needed in the fuel injection wiring. Upon hooking up the fluke meter to the output of the alternator I only read 12.5 volts, not the 14.4 like I should be reading. There is a two wire plug that goes into the alternator as well. The red wire I have going onto the output post on the back of the alternator. The white wire goes into the wiring harness and to the voltmeter I am assuming. Any thoughts? Alternator has been tested when I left the parts store and comes with a lifetime warranty. Battery is brand new as well.

 

The white wire goes to the "Choke" light.

Does that light come on when you turn the key on with the engine not running? If not, try changing the bulb.

 

i don't have a choke light anymore. I have a chokeless holley carb on there and where the factory guages were there are all autometer guages now. I was just assuming it went to the voltmeter since that's how older cars were wired. Since it goes to the choke bulb, is this wire even needed anymore then? Or is this another wire i can cut?

 

Yes you need the bulb. If you tore it out, then that's why your alt isn't charging.

The only way the alt "knows" that the ignition is on, and therefor that it's time to charge, is by way of that small current that comes through that bulb.

If you don't have the bulb, wire a 100 ohm resistor from switched ignition (the fusebox is a good source), to the terminal with the white wire.

Sounds like you're a little too fond of your dykes for your own good. You should learn and understand what things do before just hacking them out.

The "Choke" bulb actually has little to do with the choke. The deal is, the choke will not get its 12V that heats it up to make it come off, if the alt is not charging; so if the alt goes out, the choke will be stuck on. I guess the smog ***** must have thought that the choke sticking closed was more important (emissions....) than the battery not charging, so maybe they made the car mfrs label their lights so informatively.

 

great thanks for the advice and i'll keep it in mind. gotta make mistakes to learn.

 

If your car is a VIN H or G, that white wire (or faded brown) would go to pin 14 of connector C1 on the instrument panel and then have a splice going to the choke heater relay in the convenience panel. There is not a 100 OHM resistance wire in this circuit. If your car was a VIN F previously, the white wire (faded brown) would go to pin 14 of conntector C1 on the instrument panel from pin F8 on connector C100. It would also have a brown/white wire spliced into it going to pin C1 on the ignition switch. This brown/white wire has a 100 OHM resistance wire in it.

 

Look at the charging system from the point of view of the alternator, looking outward; regardless of what the schematic shows, one way or another, the alternator needs to see switched ignition through a few tens of ohms of resistance, looking out of that terminal.

Also, don't forget that this car has been heavily worked over; and no matter what wire went in what connector when it was new, whatever was behind the dash that it hooked to, is now gone. This situation is alot more like wiring a street rod or a boat, than like repairing a stock-condition car that is just broken.

Incidentally, the choke heater relay coil is in parallel with the bulb. It operates exactly the same as the bulb: i.e. when the alt is not charging it operates and cuts off power to the choke, but when the alt is working, the relay drops out and allows power to pass to the choke heater.

Here's the schematic of the original circuit, for reference. What you need to accomplish is to duplicate the electrical properties of the "Volts Indicator " (which is actually the "Choke" light) and the choke heater relay, so that the alt has the signals it needs in order to work.

 

RB - i recently had a problem where my treble light slipped dwon the side of the alternaotr while working and grounded the red output terminal. Now the guage reads below 12 and the alternator is not charging. The alternator tested fine non a bench test at the parts store though. Could the resistor in that "signal" line gotten fried?? Mine is an 85 with the guage (not light).

 

i have the same problem but my alternator uses the 5-pin wireing harness. do u guys think it could be cause i took the buld out of my SES light? also all the lights went out on my dashboard one night, could that be related?