Alternator fire!

Topic: Alternator fire! (Read 2643 times) previous topic - next topic

Alternator fire!

July 28, 2005, 01:01:44 AM

Coming home, my alternator caught on fire just outside the neighborhood. Just replaced it a little over a month ago due to the old one beginning to fail. Any reasons other than faulty alternator that it would burn up? Was just a normal drive home (with exception of an accident on the bridge heading into washington causing some heavy traffic). Headlights didn't get extra bright or dim (well until it hit the bucket and they began running off battery).

I hope the radiator hose and all connectors are okay (have to look in the morning)

Edit:
I can't tell whether its the connector (wiring) or the alternator at fault. The connector is now singed and is shorting. Either way, both connector, wire, and alternator are toast. Will deal with rest in morning.

and yes, battery is disconnected

Re: Alternator fire!

Reply #1 – July 28, 2005, 02:32:33 AM

That blade-style connector is pr0ne to causing a fire. As it ages it becomes loose, which builds heat through resistance. One great way to remedy this is to do a 3G alt. swap.

Joe

Re: Alternator fire!

Reply #2 – July 28, 2005, 04:27:07 AM

You NEED to replace the connector EVERY time you disconnect it. Same exact thing happened to me. A week or so before it happened to me I took my alt. out to change pulley and reinstalled it without replacing the connector. So the story goes, you're supposed to replace it. It's been a while but isnt there a fuseable link or something like it that disconnects so you can replace the whole connector?

Re: Alternator fire!

Reply #3 – July 28, 2005, 09:37:07 AM

Quote from: joefriday

That blade-style connector is pr0ne to causing a fire. As it ages it becomes loose, which builds heat through resistance. One great way to remedy this is to do a 3G alt. swap.

Joe

yeah, been planning on it. Where should I cut the wires to splice new ones onto (if not going 3G).

edit:
Need a good location since the wires are messed up a way back.

The plug itself, it WAS replaced, but not by me (didn't want something like THIS to happen). The alternator itself didn't come with a new plug. Either way, I guess I'll do everything myself from now on. The plugs themselves, how do you attach the wire(s)? I haven't seen an empty plug so I have no clue whether they come with wires hanging out, you need to crimp them down, or what. Also, it appears that there's actually only 3 wires total going to my alternator. On the voltage regulator, ground is just hanging there going to nothing (care end tapes up with electrical tape). 2 of the 3 wires going from the output appear to have just been connected to the main line. To help resistance from the connector and splicing? I'm guessing where the 3 meet is where the new plug's wires were spliced in.

I'm just curious on why the ground for the regulator goes nowhere.

Now on the alternator bracket. I know where it needs to be shaved on the TC, but how about on a 5.0? It looks like it has plenty of clearance although I'm not sure since I don't have a 3G sitting around (hopefully will have one this afternoon). Wiring: 4 gauge going to battery stud on starter actually the proper area? Claims so on NATO.

Re: Alternator fire!

Reply #4 – July 28, 2005, 10:22:28 AM

From what I understand...you need to change that plug every time you change the alternator itself. Pretty much all new alts come with the plug in the box, with strict instructions on changing it. You essentially cut the stock wiring a few inches back and crimp on the new harness (it comes with metal butt-splice connectors already attached, and usually heat-shrink tubing also). It's not that big of a deal to do...just so long as you do it.

Once the harness has been changed I don't see a compelling reason why you'd need to keep changing it every time it's simply unplugged. That doesn't make any sense. An inspection of the connections first, and of the wiring itself, will yield all the results you need first. Of course, it doesn't hurt to keep changing harnesses--it just seems like overkill to me if you've already made the effort to ensure the connectors and wiring are safe. Then again, I've never had an alternator fire...

Re: Alternator fire!

Reply #5 – July 29, 2005, 02:58:49 PM

Picked up a 3G - they searched by "95 mustang". Adding a tiny spacer for clearance makes it so I can no longer get the pulley tightened. It seems to tighten by hand but they (the store) say there isn't enough grab for them to tighten it down. Are there any 3G's with a longer pulley bolt or which pulley, from what car, should I look for? The only pulleys they had laying around that would work were 4rib, not 5.

Re: Alternator fire!

Reply #6 – July 29, 2005, 03:24:29 PM

I just had this problem. Had a Pro-Start reman from Pep Girls originally; both the large stock and underdrive pullies fit great. Then it ped the bed...got another one, again, no problems with the pullies. And once it died (a month afterward), I got upgraded to a Bosch reman. Stock pulley on that one is identical in size to my u/d one; however, my aluminum u/d pulley locked up the alternator and would not allow it to spin. I had to concede and use the one that came with it. I cannot explain why it wouldn't work, but I took the shop manager's word for it.

Did your alt come with a pulley at all? It should have. And I believe we're running 6-rib belts.

Re: Alternator fire!

Reply #7 – July 29, 2005, 03:27:01 PM

I used my stock T-Bird pulley with a thin (about 1/16") shim. There were just enough threads to "fill" the nut (the stub was flush with the nut after tightening). I didn't use the lockwasher either, but made up for it by using locktite.

And you will need the shim. If you don't use it, when you tighten the pully down it won't turn because the backside of it is touching the alternator housing.

Re: Alternator fire!

Reply #8 – July 29, 2005, 03:31:24 PM

6 ribs for her pleasure it is, had to change my alternator out last night so I got a good look at it. When I picked up mine I just had Napa swap over the old pulley to the new one, no probs. Now as for the plugs, I didn't change mine as they looked perfectly fine, un-stressed and uncracked. Just put a bit of Die-electric grease on the new alt's plug tabs and put in the old plugs. Hopefully I should see any problems. Oh, while i'm thinking about it, anyone run into an issue where the plugs are on the opposite side in comparison to the old alternator? It caught me off guard when I saw that, but everything fits perfectly fine still. :dunno ?

Re: Alternator fire!

Reply #9 – July 29, 2005, 04:13:38 PM

Quote from: EricCoolCats

Then again, I've never had an alternator fire...

Better watch it Eric. Gonna curse yourself. :giggle:

Quote from: nirvanagod

Oh, while i'm thinking about it, anyone run into an issue where the plugs are on the opposite side in comparison to the old alternator?

If I remember correctly I think my connector was in a diferent location on the new alt than the original as well. I did think it to be weird but all works fine. I too didn't change the connector. Just as nirvanagod, just some die-electric grease. All has been well going on a year and a half now.

Re: Alternator fire!

Reply #10 – July 29, 2005, 08:19:14 PM

Quote from: nirvanagod

Oh, while i'm thinking about it, anyone run into an issue where the plugs are on the opposite side in comparison to the old alternator? It caught me off guard when I saw that, but everything fits perfectly fine still. :dunno ?

I had same issue, after several times back to Advance AutoParts, trying two different alternators I reluctantly put the unit it, but did have to cut the accessory bracket a little bit in order to clear the new position of the connector. Its just rotated from the original's position..

Re: Alternator fire!

Reply #11 – July 29, 2005, 09:44:31 PM

I just bought a pulley from an alternator shop during lunch today and had it installed. Will get it all wired up now. 3G is easier than it originally seemed (didn't know the bracket was aluminum)

Re: Alternator fire!

Reply #12 – July 30, 2005, 12:19:06 AM

Everything but the charge/discharge gauge works (it goes down with say the turn signal on), but the battery terminals are at 14.56v idle, 14.3 with everything running. Ideas?

Re: Alternator fire!

Reply #13 – July 30, 2005, 12:45:52 AM

man the best I can tell you is to do it this way. http://rothfam.com/svo/3g/ That is the way I did it in my 84 T/C and every thing worked even the batt light works right. SOrry I don't have a guage. check that link out.

Re: Alternator fire!

Reply #14 – July 30, 2005, 12:35:37 PM

The only thing I can think of is the I and A wires are backwards, but it regulates the voltage just fine so it must be correct