Alternator problems

[bax]

yep blew up 2 of them today. Don't know what I did wrong. It's been working since I got it running. Thursday I noticed the volt meter only showing 11 V when running. Took it to the auto shop and checked it out and it's not putting out any juice. Got another alternator and hooked it up. It showed 14V running when I started the truck. Cool it's charging. One test drive about 100 yards down the road 12v and no juice. Any Ideas?

 

[evil69]

What kinda alt? G3 stock?

 

[garberz]

Do you still run a separate voltage regulator?

 

[Hoppy]

mine was the mega fuse with the 3g alt

 

[bax]

It's a G-2 with built in regulator. It has 2 funky plugs I checked out the wiring I don't see anything wrong with it. But I am kinda blind.

 

[garberz]

Where's RRRAAAYYY2? I'm sure he would have some insight.

 

[bax]

Where's RRRAAAYYY2? I'm sure he would have some insight.

I had to talk to Ray's dad to figure out how to wire it the first time.

 

[RRRAAAYYY2]

Everytime you replace the alternator you are supposed to replace the large plug. But that usually only causes a fire, not a fail.

Could it be you just have had two bad alternators? If they are rebuilts, the quality should be suspect. Lots of companies try and save the stators because they test good, but they really are junk.

I would take the alternator off and have it tested. How many miles was on the first one? What is your amp draw on the truck, i.e. have you added anything? The 2G is not a high output alternator. How old is your large plug, and how is it wired (to the battery? or to the dash)

 

[commoncold]

I'm leaning towards regulator issues. This doesn't necessarily mean that the reg itself is the problem, I just think something is CAUSING it to break. I had an external reg that went bad because of a large short...and what do you know, the alt wouldn't charge until I replaced the reg.

I don't know the details about your wiring but these are some possibilities: a large electrical spike (maybe from the starting solenoid issues), a short, or fuse problems.

For your situation with an internal regulator, ray2 might be more help than me. However, I have a lot of experience (from months of trouble shooting) with electrical systems on these broncos. So if it turns out to be any external problems in relation to the alt, let us know.

BTW, when did the last one break and what were you doing with the truck at the time?

 

[bax]

Everytime you replace the alternator you are supposed to replace the large plug. But that usually only causes a fire, not a fail.

Could it be you just have had two bad alternators? If they are rebuilts, the quality should be suspect. Lots of companies try and save the stators because they test good, but they really are junk.

I would take the alternator off and have it tested. How many miles was on the first one? What is your amp draw on the truck, i.e. have you added anything? The 2G is not a high output alternator. How old is your large plug, and how is it wired (to the battery? or to the dash)

Whole system is about 8 months old. Both alternators are rebuilds. Yes I added 2 spal cooling fans. But that was about 2 months ago. Large plug was new with the first alternator. Wired to the battery. Fuseable link wire. Without 12 volts this motor of mine wont run worth a crap.

 

[RRRAAAYYY2]

I would have the alternator checked out. If it itself is a fail, take it back home. Remove the regulator from the back, and then undo the 3 thru bolts. Seperate the front from the back, and look at the stator windings.

You should notice that there is three sets of wires wound around inside the stator. Are the wires all the same color? Or is one set darker than than the rest, usually the middle row. Also check to see if there is a push on connector between the stator and rectifier bridge.

Another thing to look at is, does the regulator say Motorcraft on it?

2G came mostly in 60 and 75amp versions. Their output is margially at best better than the older small externally regulated units. So the two big fans could be eating the alternators. I am not fan of 2g's at all, and I am surprised John didnt try to talk you out of using these in the first place. The only good thing I can think of is, you already have all the difficult wiring done for a 3G.

 

[RRRAAAYYY2]

Also too, you can call me at 1-888-214-7774.