Alternators???

[Hedgehog]

Okay so, my Jeep is ready to be registered and while doing a final run through the distinctive odor of burning electronics accompanied by smoke from the alternator. Suddenly a piece of equipment that was pumping out ~14.5 volts is dead. Question, is there something I could have done wrong? Admitting a failure time, while changing out my oil pressure sending unit I touched the wrench against the terminal on the back of the alternator and there was quite a short, a short sparky short, but only a short one ..... ..... sorry couldn't help it. Could the short have destroyed the electronical goodies inside the alternator? Honestly this $100 bill is going to hurt.

 

[ThisGuyUKnow]

Okay so, my Jeep is ready to be registered and while doing a final run through the distinctive odor of burning electronics accompanied by smoke from the alternator. Suddenly a piece of equipment that was pumping out ~14.5 volts is dead. Question, is there something I could have done wrong? Admitting a failure time, while changing out my oil pressure sending unit I touched the wrench against the terminal on the back of the alternator and there was quite a short, a short sparky short, but only a short one ..... ..... sorry couldn't help it. Could the short have destroyed the electronical goodies inside the alternator? Honestly this $100 bill is going to hurt.

Yes it could have fried something. Although I have done this more than once or twice and did not have the alternator burn out

 

[Hedgehog]

My worry is that somehow I've mucked something electrical up and it destroyed my alternator. Everything is behind a fuse so I would think the system has safeties built in. The Jeep is relatively stock, no stereo, no amp, no extra lights added yet.

 

[mtnwhlr]

They are pretty easy to rebuild and the kits are cheap might be something to try.

 

[Hedgehog]

Okay, where to get rebuilding kits.


Edit: been looking, can't find the exact model I have.

 

[gert]

What model alt do you have usually NAPA carries rebuild kits for most alternators

 

[Hedgehog]

There's a shop here in town that rebuilds Alternators that has a great reputation. I'm going to drop mine off and have them install what they call a single wire regulater rather than the two wire version I have now. From what is written the single wire turns on at very low RPM's. Sounds exactly like what is needed on a Jeep.

 

[IOPort51]

There are a lot of different opinions on the one vs two wire. The big question for the rebuild guy is what happened to the original to kill it.

 

[Hedgehog]

Been there, thought the very same thing. One of the good parts about having the local guy rebuild is he will look at the whole alternator to evaluate it's condition.

 

[PaRenegade]

My guess, and I'm no electronics guy so it's merely a guess, is a diode got shot from the surge of heat when you... basically welded on the terminal. You added heavy two way traffic to a one way street and someone ran over the traffic cop, if my guess is correct. I believe diodes are like check valves in plumbing.

 

[Hedgehog]

Talked to the rebuilder when I dropped the alternator off. His opinion is very similar to yours. But I can't help but wounder, the electricity didn't actually change its flow direction and the engine wasn't running when the short occured. The flow should have gone from the battery to the nearest ground which was through the wrench into the engine block. Big amperage did flow though. I don't know, electricity is a wild beast and this mistake cost me over $100.

 

[PaRenegade]

I don't think it was so much the flow of amps, I think it was more the heat generated. I mean, it's enough to melt steel even with a quick spark. Just my thought.

 

[Hedgehog]

No argument from me, something most certainly happened.....

 

[Barry2]

Get it reinstalled and running yet?

 

[Hedgehog]

The rebuilders are backed up from taking time over the holidays. Usually it takes a day to rebuild, but mine won't be ready until next Tuesday or so. I admit to be chafing at the bit to move on with getting the "Witch" registered and on the road.

Something interesting came to light while talking to the rebuilders. Since I have no idea what the output of the alternator is I asked them if they knew or could find out. Their response was interesting. Since the alternator had been rebuild at least once already the felt the output would be in the 60 amp range, BUT for $1 an amp they could increase the output to 90 amps or even 110. Exactly how that is done is beyond me. My little brain thinks more windings or bigger magnets or both would be required. Maybe it's a simple matter of hot rodding the regulator. I really don't know and didn't want to bother the tech. with to many questions.

 

[Torxhead]

I was wondering if you have fusible links tied into your electrical system. This could have prevented frying that alternator. Some auto electric shops do have a measuring device for the output of alternators, with some searching you might find a shop to check this. If you need more juice like to run a winch, adding another battery would help more than a larger alternator. Those off road lamps suck a lot also.

 

[Jimbos76cj]

Why did you take it to a rebuilders? I take mine to my local advance or auto zone. They put it on the tester and tell you what's wrong with it. Unless you have melted the winding every thing else is easy to replace. I haven't bought a new jeep alternator in about 10 yrs. very easy and the only special tool is a piece of clothes hanger.

When ever I part out a jeep I pull the alternator, have it checked, replace the brushes and either resell it or store it for later. Rock auto sells almost all the parts needed.

 

[Hedgehog]

Jimbo -

I know what was bad, mostly from the smoke that I saw roll out of the alternator. The Diode fried which burned up the regulator.

Why did I have mine rebuilt by a local shop? ...... They came highly recommended by a guy I trust.

Why not rebuild it myself? ...... I looked on line and could not find one that matched my case exactly.

They worked with me. ...... My alternator had a standard two wire Delco-Remy plug, they converted the alternator to a single wire set-up. 12 volts directly from the battery, no other wires to muck around with.

Why not do it myself? ....... I almost did. Next time I probably will.

Torxhead - A fusable link would not have saved this alternator. I shorted at the post where the battery power goes into the Alternator directly to the engine block. As I wrote before, yes I know I shoulld have taken the ground wire off the battery. Unfortunately I was focused on replacing the oil pressure sending unit and never thought twice about the battery. Live, learn, spend money......

These guys have been rebuilding alternators ever since Henery Ford invented assembly lines, I'm sure they have a tester. It's likely they will tell me the amps it can produce. I really don't need much power in the Jeep. About the only extra electrical draw the Jeep will have will be the KC lights in two sets of two. I expect to only use them occasionally.


Well, just got a call from the shop. My alternator is done. Even when busy less than a 24 hour turn around, not bad at all.

 

[PaRenegade]

I was wondering if you have fusible links tied into your electrical system. This could have prevented frying that alternator.

The link will let the power flow either way through it but only for a short time, and you drew way more than 40 amps(I think that's what size it is). So you may want to inspect the fusible link and make sure it's okay also. Or just replace it to be safe.
Again, I'm not an elec. guy, but I get some of it. (or I make damn good guesses )

 

[Hedgehog]

Alright, where would the fusible link be? As far as I know there aren't and fusible links in my Jeep. Besides it wouldn't have helped a direct short through the wrench, at least I don't think it would, you never really know where wild electricals will go when they're turned loose.