Alternator Question

Normally, the problem with an alternator conversion is in getting the wiring correct so it WILL charge. Your problem is the opposite, so I'm going to suggest that the used alternator has another internal problem. Of course, it *is* always possible that the regulator you just replaced is also bad, it wouldn't be the first time an off-the-shelf part was defective. If it were me, I think I'd spring for another alternator, rather than dumping more $$$ into this one.

 

You could go the one-wire route, but it really doesn't gain you anything other than two less wires to connect.

The three-wire unit has the big 6-8 GA wire from the back stud to the battery, a 12v wire from the ignition switch to the side plug, and a third wire from the side plug to the indicator light, if used. The 12v wire from the ignition tells the alternator to start charging, and the internal regulator tells it when to stop.

The one-wire unit simply shuts off at low RPMs, such as at idle. It is internally excited, so it doesn't need the 12v sensing wire from the ignition switch. They're also a little more expensive. You can also get a kit to convert a 3-wire GM alternator over to a 1-wire, but that is assuming that you have a good, working alternator in the first place.

Hope this helps!

 

Hmmmm. My one wire alternator charges good at idle.

 

Here's an excellent reference page, far better than I can describe here. I've got the three-wire unit, but its not wired in permanently. Until the thaw comes, I'm relegated to the rat's nest of jumper wires under the hood....


http://mightymo.org/Proj_OneWire.html#How it works

 

Mine too. If I have the headlights and heater and wipers on, it drops to about 12.5v at 500 RPM. Anything above 550 or so, and it'll sit at 13.5-14v...

 

Yeah, I know. I read somewhere about how to change the RPM at which the alternator will kick on, but I'll be durned if I can find it now. I thought the 3000 RPM figure was a tad high, but most alternators are overdriven by their pulley arrangement anyway...

 

Welllll, the old regulator shouldn't be connected when you are using a Delco alternator, since the Delco is internally regulated. It should be disconnected.

 

Hokay. here's the skinny on wiring up a 3-wire GM alternator.

The big stud on the back of the alternator should have a #6 or #8 wire run from it directly to the (+) terminal on the battery. Use good crimp-on rings, and solder them for good measure since this wire carries the rated load of the alternator when the battery is deeply discharged, or you have a lot of draw.

The #1 terminal on the side plug is for the indicator light in the dash, if you use one. If not, just leave it disconnected and it won't hurt anything.

The #2 terminal needs to be run to the "cold" side of the ignition switch, so that you can shut everything down when you turn off the key. Some folks will take the easy way out, and just run this to the big stud on the back and call it good. Unfortunately, there is always a slight drain on the battery this way, and it will go dead eventually when sitting.

One of the most common wiring mistakes folks make when messing with the alternator wiring is to end up back-feeding the ignition system so that cutting off the key will not kill the engine. if this happens, look at where the #2 wire is hooked up and you will likely see your problem. The power to the #2 wire must no be allowed to backfeed the ignition.

Clear as mud?

Tater, I'd pull the harness off the old regulator as you did before, and run a temporary jumper from the #2 terminal. Fire the Jeep up, and touch the other end of the jumper to the + terminal of the battery. You should hear the engine bog down slightly under the alternator load when the alternator kicks in. It sounds to me like you had the old regulator trying to 'help' the new alternator and the result was the overcharging condition. Once you get the Delco sorted out, you'll prolly never have to touch it again!