Ok, guys, here's what's up...I've got my 95 Cavy, and a high-output alternator that I want to put together. I'm getting started on my system, and need to upgrade the alternator to feed it. I've got the alternator mounted, and have it wired, and am having issues. To avoid me having to retype the whole deal again, here's a cut-n-paste from what I posted over at the12volt.com's forums earlier today:
I've got (obviously) a 95 Cavalier that I'm upgrading the alternator in. The alternator is a high-output unit, of an unknown origin, that I picked up from a local stereo shop some years ago, which is now gone. I'm just now getting around to getting it installed in this car, since I'm finally starting the install. I'd had it in another project car, but it never saw any use, it just got installed, so I'm struggling with the wiring on it. To make matters worse, I sold the other car, and the buyers pulled this alternator for me, and removed the wiring from the regulator to the alternator, so I'm having to reconstruct it "on the fly." Also, I need to integrate it into the car...So, I'm in need of some serious help here.
Now that you've got the background, what I've got is a small-case GM alternator that resembles that off of an early '80s GM truck. We've modified the case by swapping the front cover with the one from my Cavalier to get it to mount in the car (it fits just fine now). It's got the battery terminal, and a standard GM plug on the back, with just a field connection, no stator connection. The voltage regulator that came with it is a modified Ford regulator (identified as modified by the pop-riveted cover and being wire-tied to the harness that was originally connected directly to the alternator, with the four terminals on it. Only three of those terminals were used with this alternator, though...the Battery terminal, the field terminal, and the stator terminal. There's a ground wire running from the case of the alternator to the case of the regulator. The I (I think that's the indicator) terminal was unused, and there was no wire to it.
In the car, the plug had three wires as well, a field, stator, and indicator wire. If I hook up the field and stator wires to the alternator in those locations, I can get it to charge, but the regulator stays energized even when the engine is off. That's my current connection, and I simply pop the hood and disconnect the field when I stop for any length of time. It's cumbersome and ghetto, but it works. Obviously the regulator isn't shutting down when the car's off, so I'd assume that it's not shutting down when the car's running either, and I'd figure that it's trying to keep the alternator charging all of the time.
Anybody got any suggestions on how to fix this and get it to work properly? I don't want to have to plug/unplug wires all of the time. I'm also thinking that it can't be good on the battery or the car's computer. Thanks!
I went by the local alternator shop today at lunch, and the guy there was totally baffled, which honestly scares the crap outta me (at least as far as his abilities goes). I think the reason the regulator isn't shutting down is because the car's computer is keeping it turned on, but I don't know why that's happening. If I pull the field connection from the car, the regulator shuts down properly and everything seems nice and quiet. Anyone got any good ideas? I'm out of them, unless I start adding relays and switching things on and off with the ignition circuit, which seems like the wrong thing to do, to me. The guy at the alternator shop pulled out a regulator to show me, indicating that he thought that was what I had, but it even seemed to be a lighter duty one (there was no obvious switching transistor, like the regulator I've got...mine's plainly evident on the back, mounted to a gnarly heatsink). I'm open to suggestions...I'm thinking mine's got to be fine, since it's working properly, just not integrating to the car correctly.
Someone's got to have an idea that I just haven't thought of...I'm open to suggestions.
Thanks, guys!
--Mike
Ok. After connecting and disconnecting the regulator in the rain yesterday, I figured I'd work up a solution. I called my mechanic buddy and had him email me some schematics of the factory wiring for my car and for a "generic" Ford truck, that should use a similar regulator (since that approximates the regulator I've got). Using those, and taking some measurements with my trusty meter, I've come up with a solution that at least works. I had previously found that with the regulator connected to the battery constantly like it was, and the stator and field wires connected, I couldn't get the regulator to shut off. Measuring, I found that the stator wire was connected to a constant 12V, which matched the wiring diagram that my mechanic buddy provided. Those two connections were what was causing the field connection to stay energized and keep the regulator "turned on," draining the battery. I ended up putting a relay in that disconnects the battery lead from the regulator when the ignition is turned off, which means that the regulator isn't allowed to stay on. Voila! No more regulator issues. And, no more standing in the rain hooking up wires underneath the hood, either...that looks really ghetto on a decent looking car, believe me...people talk.
I'm gonna be looking for a better source of switched ignition, since for the time being it's just running to the base of a fuse in the aux fuse box next to the battery. But it's working correctly and everything is functional as it should be.
And man, does that alternator hum...much louder than the stocker. It's quite a bit larger amperage, though...something along the lines of 180-220 amp, I believe. Should be good enough for the rest of the toys, since I'll need a good chunk of that additional current at some point or another.
--Mike
