Alternator SPARKING!!!!

So I went out to test out my new 10k winch today and I ended up buring my jeep deep in a mud hole. I ended up winching out but as I was reving the engine up while pulling myself out sparks were coming from the engine bay. So then I just started winching alone and no sparks.

Anyway, after we got the jeep out of the hole and onto dry land I realized that at high RPM's the wires for the alt were sparking. I found that the upper single wire for the alternator had almost completely burnt off and was sparking. Then I removed it, and taped it up and decided to try it again...it still sparked but it looked like it was coming from the same area.

Anyone know is this a winch related issue?
What is the single upper wire on the alternator used for? (ground? positive to bat?)

Also my alternator is still under warranty, so I plan to replace it and put a new end on the single wire. Any clues on why this would happen would be great.

Also for refrence its a 1993 Jeep Cherokee 4.0L AX15. I'll take and post some pictures tomorrow.

http://www.geocities.com/JeepI6Power/sjg-id.html

Scroll down to the third set of pictures - that should be about what your alternator looks like. Pay attention to the pic on the right - it's the backside, where all the connections are.

There will be three or four ring lugs attached to the back of the alternator case. One will probably be attached to the case, or to the mounting bracket - that's a ground, and there's no reason for it to be sparking.

Look at the top left of the pic - there's a pair of terminals with a single plastic insulator piece. That's the feed for the field coils (from the regulator,) and that's fairly low voltage and current (1-4VDC, and about an ampere or so.)

Top right - you'll see a single stud with a large black surround. That is the feed from the alternator to the battery, and it's 12VDC at whatever the regulator decides the system needs for current. That is probably the wire that is sparking, no?

Chances are, you've gotten that connection contaminated, and that's what's causing the sparking. Disconnect the ground at the battery, then disassemble and flush that connection (distilled water is acceptable. Electrical contact cleaner is best. DO NOT USE WD-40!)

You've sunk it in a wet mudhole, and that's what probably contaminated that connection. I don't know why the alternator is at the bottom, but it is - and we just have to work with that.

Thanks. The one on the top right is the one that was sparking.

I tried to trace it up through the wire loom but because it was dark I couldn't figure out exactly where it went. So, that connection you say connects to the negative on the battery? Do you think the connection to the negative terminal is contaminated? It's still the stock battery terminal clamps so I can't really disassemble the connector for the battery.

Do you think this is related to the power being drained from using the winch that melted this lead?

I'm just kind of lost because I've never really seen that happen before. I was even thinking of upgrading that wire for the alternator but I don't really see any reason since the new alternator will be stock so it shouldn't put out more power than that wire can handle.

Its the positive for the Batt. If the wire is damaged I would replace it. at the least just take it apart and brush the connection, if ther wire and connector are in good condition rinse and reassemble. It is a combined problem, mud/corrosion on the terminal and a heavy draw from the winch. While your at it go ahead and clean all grounds you can find and start doing so PM, people allways overlook the small stuff but it really is important.

Ok, The wire just looks to be burnt only where it was exposed and connected to the alternator. It does look like the power from the alternator was contaminated right there.

I'm going to try putting a new end on it and using some heat shrink tape/ dielectric grease to try and prevent this from happening again

Thanks for the help guys!

Heres some pictures of the fried alternator...

I ended up putting a new end on the wire and putting some dielectric grease on it.

I am having a problem with my 91 xj.I just did a motor swap and there seems to be 2 heavy guage wires.One is thicker than the other but buth have ring ends.I take it the large one is the alt to bat wire but what does the smaller heavy wire go to?
I need to know where that hooks to asap?

1badass4x4 said:

I am having a problem with my 91 xj.I just did a motor swap and there seems to be 2 heavy guage wires.One is thicker than the other but buth have ring ends.I take it the large one is the alt to bat wire but what does the smaller heavy wire go to?
I need to know where that hooks to asap?

Click to expand...

I think you are talking about the Alternator-to-Starter Relay and the Battery-to Starter-Relay connections. There should be another 5 connections or so to that same stud.

not sure if I am reading you correctly, but sounds like the one going to the starter.