3G alternator issue

[JK]

I've got a question for the one and only Viperwolf. I have a 69, 302, 3 spd, with 3G conversion and a full MSD ignition. I did the 3G conversion a month or two back. Its been working like a champ and charging fine. The other night, I went out and did some adjusting to my throttle return springs the other night, which required that I start/rev/kill the motor 3 or 4 times. Then it sat for 2 days and this morning, I go out and it's dead. I throw it on a chargeer for a few minutes, and get it to fire off. I check voltage and it's dropping, so I'm obviously not charging. I have it wired correctly, and I do have 12 volts in run at the black/green. I run a single v-belt, and to date have never had squeal problems with the exception of one night, and after I stopped/started the engine it went away and never came back. I had the Alternator pretty dang tight, so I'm wondering if that destroyed it. Any other troubleshooting ideas, before I replace the alternator? (It's under warranty, so not a big deal, just an ass pain.)

 

[BUCKNBRONK]

Im not the one and only VW but I'll give it a shot-

what is ur rpms at idle? newer alts dont like low idle. plus some need to be pushed to 1200rpms +/- to "excite" or start the charging process then they should do fine at a lower rpm. my guess is u lowered the rpms while messing with the spring and now the 3g is not kicking on. If ur below 600rpm at idle kick it up. but that does not explain why ur bat died, any chance u left something on?

I shall await my schooling if any info I have given is incorrect-

 

[JK]

I never thought of that honestly. It idles at about 800-1000, so not sure that would be an issue, and it's worked fine up until now. I might see what it does holding the idle higher.

 

[bronco_daddy]

I run a speed pulley from RJM because of this

 

[Viperwolf1]

Did you check for 12V at the alternator excitation terminal? That's the green-red wire here: http://www.oldfuelinjection.com/public/alternator/3G-ALT_wiring.gif If you don't have 12V there with the key ON the alternator will not turn on.

Another thing to keep in mind is the belt can slip without squeeling. A dead battery will certainly put enough load on a single v-belt to cause it to slip. If it slips it will not charge.

 

[JK]

I said black/green above, I meant red/green. It did have 12V there. I decided to just yank the alternator and take it in for testing. I checked everything over one more time when I got home tonight, and all voltages were good, battery was charged while I was gone, and while running, the belt was tight and everything was turning as it should. Still no power. I help the carb to a high idle, and it didn't change anything. I pulled it and sure enough, the rectifier checked bad. I put the new one in and bam! Everything is charging and running fine again. It was under warranty, so no money out, just time. I would say that I'm one of the lucky ones whose problem wasn't too hard to find, and that everything went well, but while pry barring the alternator in place I put a sweet gash in the heater core coolant line!

I had some hose laying around, so now it's fixed, but what a pain! I ran it for a bit, but it's low on coolant so I wont be messing with it anymore until after I pull the radiator and throw in the 4x4x2/front discs/hydroboost this weekend. Thanks for all the replies and suggestions. Now I just have to hope it was a bad alternator from the manufacturer and not my Bronco frying them!