Fried Alternator Wire

DanEC · #1 (**permalink**) 08-04-2014, 10:06 AM

If it wasn't for electrical issues I wouldn't have many issues. Setting the timing on my car this morning and noticed the orange wire to the alternator had fried insulation.

I started disconnecting wires and found the orange wire was very loose. How it didn't get tight or loosened I don't know.

I stripped about 2 to 2-1/2 inches of crispy insulation back and that appears to be as far as it went. All the other wires look fine. I'm suspecting that due to the loose connection I was getting arcing across the wire connector and alt terminal that generated the heat to melt the insulation. I've noticed lately some jittery movement in the amp gage so I suspect that was from it also. All sound reasonable??

I wrapped the wire back up and put a couple layers of heat shrink tubing over it all, cleaned the terminal and bolted it back tight - this time with a tooth washer for good measure.

I took it for a short ride and it all seems fine now. Any concerns?

strictlypersonl · #2 (**permalink**) 08-04-2014, 10:29 AM

The orange (power) wire has a direct shot to fuse 2 (passenger's side). Any "short" can only be between the alternator and the fuse panel.

MOTORHEAD · #3 (**permalink**) 08-04-2014, 10:29 AM

Whoa !! Major melt-down ! That orange wire is the output cable/terminal, and it was dead shorted to something !!! The fact the insulation was melted only a few inches tells me it was grounded some where near the alternator. Looking at the first pic, it looks like it shorted right to the alternator case, look for some black arc marks in that area. Insulation was probably touching metal and wore thru due to vibration and shorted(grounded ) on the engine or alternator. Lucky there was no fire !

DanEC · #4 (**permalink**) 08-04-2014, 10:53 AM

The fuse is OK and I don't see any shorting tracks to the case. The orange insulator ring around the alternator post got a bit scortched from heat. The eyelet , nut and washer securing the terminal had signs of shorting like arcing. My theory is it didn't so much short as just get real hot from the increased resistance.

I suspect Motorhead is right that the eyelet insulation was pinched and worked off leaving the connection loose.

DanEC · #5 (**permalink**) 08-04-2014, 10:57 AM

Bob - do you think I need to replace the length of orange wire? Looks like it would be quite a job to unwrap and re-wrap the harness but certainly do-able.

Gaz64 · #6 (**permalink**) 08-04-2014, 12:53 PM

Dan,

You are correct in your analysis of your problem.

You'll find the ring terminal is not large enough in cross sectional area to carry the current draw required. Combined with a loose nut and/or poor crimp to the wire, and the connection overheats.

Seen it many times, still see it today in modern cars.

DanEC · #7 (**permalink**) 08-04-2014, 04:49 PM

Quote:

Originally Posted by Gaz64

Dan,

You are correct in your analysis of your problem.

You'll find the ring terminal is not large enough in cross sectional area to carry the current draw required. Combined with a loose nut and/or poor crimp to the wire, and the connection overheats.

Seen it many times, still see it today in modern cars.

It did get hot - I noticed when I was through, 2 spots of solder on top of the frame rail. Apparently the ring had been soldered on and it melted and dripped down. I wonder if there is any detriment to the properties of the copper wire from the heat (Bob ??). Not sure if I need to replace the wire in the harness or maybe just strip it back again and re-solder the ring and insulate it back.

patrickt · #8 (**permalink**) 08-04-2014, 05:24 PM

I think you fried the wire back when you couldn't get it to charge properly and you were jumpering the voltage regulator. Jumpering the feed from the VR, to try and find the original problem had it running at absolute 100% max output if you revved it up past 1500 RPM or so.

DanEC · #9 (**permalink**) 08-04-2014, 08:17 PM

Quote:

Originally Posted by patrickt

I think you fried the wire back when you couldn't get it to charge properly and you were jumpering the voltage regulator. Jumpering the feed from the VR, to try and find the original problem had it running at absolute 100% max output if you revved it up past 1500 RPM or so.

Patrick

I think I would have noticed it before. Plus, I've noticed some twitchiness in the amp gage the last time I drove it. Pretty sure it just happened.

strictlypersonl · #10 (**permalink**) 08-05-2014, 07:57 AM

Quote:

Originally Posted by Gaz64

Dan,
...You'll find the ring terminal is not large enough in cross sectional area to carry the current draw required. Combined with a loose nut and/or poor crimp to the wire, and the connection overheats.

After about 1000 ERA kits that have worked fine with that eye-ring, I suspect the problem was a bad physical/electrical contact somewhere at or near the ring. For those using high-draw or high-output charging systems, I've occasionally supplied a different feed wire that bypassed the ammeter circuit - the real limiting factor.

strictlypersonl · #11 (**permalink**) 08-05-2014, 08:01 AM

Dan,

Ideally, I'd replace the entire wire. A splice is possible but ultimately a weak point in the circuit.

patrickt · #12 (**permalink**) 08-05-2014, 08:05 AM

... and Dan, you don't have to remove the old orange wire, just clip it at the alternator, and clip it at the fuse box, then run the replacement wire from the the alternator to the fuse box.

DanEC · #13 (**permalink**) 08-05-2014, 08:37 AM

Quote:

Originally Posted by patrickt

... and Dan, you don't have to remove the old orange wire, just clip it at the alternator, and clip it at the fuse box, then run the replacement wire from the the alternator to the fuse box.

Quote:

Originally Posted by strictlypersonl

Dan,

Ideally, I'd replace the entire wire. A splice is possible but ultimately a weak point in the circuit.

Patrick - that's a good thought. I could just overwrap it back into the harness and leave the old wire in it. Interesting - I have an old transister ignition Corvette and when the TI distributor option was ordered they just clipped the old ballast resister wires off in the harness and back tapped them at the factory - then ran a additional harness for the amplifier. Pretty much would be the same thing.

Bob - I'll call John and see if I can work out something with him to get a new orange wire of correct harness length and connections made up.

Thanks.

patrickt · #14 (**permalink**) 08-05-2014, 08:45 AM

Quote:

Originally Posted by DanEC

I'll call John and see if I can work out something with him to get a new orange wire of correct harness length and connections made up.

It's just a 10 gauge orange wire with a crimped and soldered eyelet on the end. That's just a trip to Lowe's....

EDIT -- and I bet you could substitute red and it would work just as well....

strictlypersonl · #15 (**permalink**) 08-05-2014, 10:24 AM

Be careful about substituting stationary-spec house wire for an automotive type. The former uses larger-diameter strands which have more of a tendency to work-harden and fracture.

DanEC · #16 (**permalink**) 08-05-2014, 10:38 AM

I want to get ERA to fab it up and use their own supply of connectors. The wire strands are pretty heavy gage. Even if they are a little leary of finishing the wire on both ends to an exact length for fear of it being off a bit - I can crimp and solder the alternator end with the right eyelet and insulator sleeve.
Then it will look as good as new.

Thanks again.

Dan

DanEC · #17 (**permalink**) 08-09-2014, 01:50 PM

Looking for thumbs up or thumbs down on my slightly crispy alternator. While waiting for the replacement wire to arrive from ERA, I pulled the alternator out to take a closer look at it. The factory plastic insulator was fried more than anticipated. I removed it (I think it actually extends all the way through the hole in the case but it came off pretty easily).

I rigged up a replacement insulator and set it in a small bed of silicone caulk around the stud and came up with this as a repair. I ran the car after fixing the fried wire temporarily and it runs and charges fine. It does not appear to have actually ever managed to short to the case or anything else. The loose connection just generated a lot of resistance that caused high heat - it even melted a small spot out of the stud.

I put it back on the mount with the intent of running it this way but after reflecting a little I'm having second thoughts. I'm afraid the remaining insulator where the stud penetrates the case may be so crispy that after a few miles it will short through to the case.

Think I should just bite the bullet and replace it?

Gaz64 · #18 (**permalink**) 08-09-2014, 02:24 PM

Yes.

New alternator and more robust terminals.

PeteF · #19 (**permalink**) 08-09-2014, 02:36 PM

Based on my experience, the risk question has two factors. First there is the probability of a failure, then the criticality of the failure. From your photo the cross sectional area of the stud does not appear to be compromised to the point of being the current-limiting area, so that would make the probability factor low. But, IF the stud is compromised where you can't see it, and you judge the criticality of another failure as moderate or high (fire potential), then the risk would be moderate/high. Lastly the time/effort/cost is not unreasonable, so I would replace the alternator. You'll feel much better when far from home. My 2 cents.

DanEC · #20 (**permalink**) 08-09-2014, 03:02 PM

I'm most worried about the insulation properties remaining of the sleeve over the stud where it penetrates the case. Originally I'm pretty sure it was one piece with the crispy fired surface insulation ring - and from the exposed edge at the surface of the case, I think it is just as crispy. I think you have both helped convince me to go get another alternator.