I put them in, they work for a few days, but over time they seem to charge less and less, then they just stop working. MY car is an 89 camaro, it HAD Serpentine belt. I switched to V-belt. The plug for the new alternator is NOT the same as the Serpentine belt plug, so i cut it off and installed the V-belt plug to my existing harness. The wires are Tan(field wire I assume?) and Red, then on the back of the alt is the 12V charge post. Where does the field wire go? apparently it doesnt like my factory field wire hookup?

if i see vader around here or on other boards he frequents i'll direct him to this thread

Make sure the AWG 8 wire is on the BAT terminal, and also a constant battery source is on the "2" or "R" terminal (regulator), and the switched ignition source is fed through a resistance to the "1" or "F" (field) terminal.

thanks ede, the title should have included you as well.
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MORE info: When i shut the car off, it DOESNT SHUT OFF! I have to get out, and unplug the alternator... then the car dies. WTF??
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My new alt, I ran A: to the factory field wire, B: to the factory red wire from the serp. alt. and C to the lug 12V constant near the batt. It seems to work fine, but then again so did all the others...

And ede is trying to remind you that if you want to contact someone directly, use PM or email. If you are posting on a publicly viewed forum or board, please don't ask for specific members' help, thus, we can avoid discouraging participation from everyone.

Something I thought of. If i wanted to replace the factory field wire deal, couldnt I just buy a 100OHM resistor, put it inline a switched 12V source and use that as my field wire?

actually Mr. vader is the one you should be asking, but a PM would of been the way to do it.

The wire you're calling the "field" wire is actually the idiot light wire. Alternators with internal regulators don't really have a "field" wire, as that is the wire that supplies excitation current to the field windings from the regulator. That's not what that is. It's the warning light wire.

Yes the 100 ohm resistor will work.

In normal operation, that terminal of the alt gets switched 12V ignition, that has passed through the bulb to get there. So looking out of the alternator through that lead, so to speak, the alt sees 12V through the bulb's resistance.

The reason the car won't shut off if you just hard-wire that terminal to ignition with no resistor at all, is because when the alt is charging, the output of the stator is being rectified not only by the main rectifier, but also by the diode trio (the small package of diodes in the alt), and that appears as 12V output at that point. The diodes can pass enough current to run the ignition system. Therefore, even when 12V is no longer being supplied through the switch, it's being generated by the alt, flowing on that wire back to the switched ignition circuit, and there's enough juice available there to work the ignition system.

The reason you're killing alternators, is because the diode trio isn't supposed to carry that much current; and it's burning out, one diode at a time. So you get 3 steps of failure.

Put a resistor in series with that wire; I'd suggest a slightly higher value than 100 ohms though, like maybe 120 ohms or 150 ohms. I usually use 120 ohms when wiring up boats or street rods or something. It should be a 5 watt resistor. You can get such a thing at Radio Shack I think, or an electronic distributor in your town for sure, maybe even an appliance parts place.

I'm not sure if that's correct.

RB83L69 probably shouldn't even be posting here, since he wasn't invited.

Out of town, sorry. Was the plug physically different? Sounds like you went from a CS to an Si gen. 89 has the CS series Delcotron. If the plug did not fit you have an older version. problem is that the gen's reg ic is being kept on, simply put it is wired wrong. Some models only used the brn wire. The field was fed from the internal trio. Does the unit buzz when the key is off? If it does disconnect one wire on the plug at a time and see when it stops. If it stops when you undo the red wire on the plug leave the brn on and try it and see if it charges. A 100 ohm 1 watt resistor can be had at any radio shack. The brn wire must be key controlled. Stock 89 wiring, and by the way the diagrams in most books are wrong the red plug wire was ALWAYS hot, even with the key off. They used the brn wire to turn the gen on and off. Look inside the reg plug for terminal markings, sometimes it's on the rear outside shell on the gen side for letters. Look for "P,L,F,S" or something similiar. Leave the red wire off and use the brn wire with a resistor and try the "L" terminal. There were several wiring variations depending on the reg IC. get back if you need more info, I have a book on the older Delcotrons I'll dig up and post the pinouts. Dan

Im a little lost on the terminology, Danno

reg IC = ?
internal trio = ?
turn the gen on and off (gen = generator?)

Now for info, Yes the plugs are different. the 89 had a black plug with 3 prongs 1 larger than the other 2, but only 2 wires coming out ofi t, 1 tan, 1 red. the red is always hot, the tan is switched 12V (I assumed the "field")

the new alt has a tan plug, 2 identical prongs. I put the upper plug to the tan wire, and the lower plug to the red wire. they are labeled only #1 and #2. #1 is the upper plug, where i put the tan wire.

When i turn the car on it seems to charge like normal. when i shut the car off, it keeps the ECU running, which keeps the fuel pump running and ignition running. i unplug the fuse on the ECU to shut the car off.

So how should this thing be wired exactly? i left it connected all last night, and started the car this morning and it still starts normal and charges like normal; but for how long? I want to get it right. i un-plugged it for now, until I understand how it should be wired. what does this alt NEED?

The diode trio is internal to the alt or gen as GM calls them, actually for some time. The ic is internal also, it controls the field. Term #2 goes to battery direct just like the rear lug, term 1 goes thru a 10 not 100 ohm resistor to the key switch. Look here, www.intelab.com/swem/gm_charging_sys.htm

Ok so its 10 ohm, not 100? so when RB said use a 120 OHM he meant 12 OHM? Hm. that appears to be the way my alt is wired up already, the red's constant 12V, and the brown to ignition (which it is) I assume the factory has a 10 OHM resistor already in that brown wire... i wonder how to check that?

lets say it does. the next question is, if my alt is wired correcltly, why does the car still run when i shut the key off?

No, I meant 120 ohms. 10 ohms is wrong. The car will probably not shut off with that little resistance.

You simply need a value of resistor that more or less duplicates the resistance of a 194 light bulb. See that thing on the schematic that calls itself "Volts Indicator"? That's the bulb. All you're trying to do, is to put something there that does the same thing electrically as that bulb, except it doesn't glow.

Notice also on that schematic that in cars with the other possible option of the resistance wire, the factory used 100 ohms. A resistor of that value will work too.

Ignore the comment about 10 ohms, that's just wrong. Nothing but a left turn off the dirt road and through the weeds, all the way into the lake. Just because it's on some web site doesn't make it true.

Disregard the 100 ohm, a 194 lamp reads 4.9-5.2 ohms, 10 ohms is fine. what turn the gen on and off is the line that is key controlled. If the car still runs do what I said, disconnect on wire at a time from the gen plug and see when the car shuts off. Then get back to me and let me know which one it is and we'll go from there.

Do your homework before you give advice. You don't know dick about charging systems. The sense or control line only needs 12 volts and usually its roughly about a half a volt less than battery, the reg ic has a target voltage around 14.5 -14.9 volts, the sense line drops it down to compensate for internal wiring drop. Measure a 194 with a dvm. Newer reg ic's replicate the ASVR ic's used in the "D" gens. Y can use up to a 2K ohm resistor to turn the gen on. Y have a lot to learn.

You know, I was told a long time ago, never to argue with an idiot, because bystanders can't tell who is who.

So I won't.... I'll merely present facts.

http://www.chml.com/assets/databookpdf/2-55.pdf Scroll down to the 194 and look at the voltage & current specs, and apply ohms law.

For the number of vehicles (including some cars even) that I've wired up over the years just like I described, I don't think I need to be told it won't work. In fact I have no doubt that I don't need it. Experience counts especially when it's successful.

Ok guys, dont argue. Ill shove a resistor inline and see what happens. if the car still runs, ill burn it and say your both wrong

but seriouselly, Ill take everyones information into account and make an educated decision. Its more than what I was doing, what with the kerosine and all.

OK 120OHM Resistor INLINE the "field" wire:

RESULTS: Car will shut off, but battery only see 12.8 Volts at idle, and 13.2 Volts above idle (wont go higher).

Should I try a lower resistance? Doesnt seem to be charging nearly enough.