alternator fire

[ss_mini14]

while leaving work today my alternator caught fire after driving down the block for no apperant reason. i got the battery disconnected and got the fire out before any serious damage was done to the rest of the car. unfortunately the harnesses going into the alternater are burnt to a crisp. i havent had the chance to really look at it yet so i don't know how extensive the damage is. the car was running just fine this morning so i dont understand why it would out of the blue just start fire. was it just a faulty alternator or is it possible there is a short to ground somwhere? any ideas, tips, suggestions or experiences would be appreciated. by the way it's an '88 colony park 5.0L with an internal voltage regulator, well...i dont see an external regulator anywhere. there is (was) a plug on top with 4 or 5 wires in it and one on the side with 3 or 4 wires in it, i don't remember exactly how many.

[Blaze86Vic]

The connectors have a reputation of burning up. In the future make sure the connector is in good condition and put a big gob of dielectric grease in it before you plug it back up.

Most will say a 3G (130amp) alternator conversion is in order. And it is a good idea, I need to do it, but for myself, my 2G (65amp) is already putting out 130amps and I have never had a problem with it. But I also keep that connector soaked in dielectric grease to make sure it has a good connection and never gets hot. Which is more likely the problem, that people don't put any dielectric grease in it and after 15-20 years it dries up and surface corrosions causes a weak connection which heats up to the point that it melts the connector.

[DarkKnight]

They say that the Alt. that come with our cars are actulay faulty... Go Fig. And the old wiring harnesse will catch them on fire.. :-( Sorry to hear about it mang.

[85crownHPP]

I still need to put a heness on the 91...... anyone know of a replacement for the green fuse link just outside it???

[gadget73]

Yeah, 3g conversion time. My stock alternator harness also burned. It didn't catch fire but it did melt down. Car died on me across the street from a meet. Got the harness rigged up enough to get me to a friend's place, and I did the swap in his driveway.

[ss_mini14]

i got her going but now the alternator isn't charging, the amp light stays on and the voltage across the battery is 11.5. i got a new alternator from autozone and a new plug with leads from checker (cant really afford a 3G conversion at the moment) then smeared a generous amount of dielectric grease on both plugs. that had to be the problem because the rest of the harness looked ok, only the plug and the alternator were burned. i think the problem now is the wire from the regulator to the feild coil is damaged internally. it was getting late so i called it a day. i'm just glad my girl wasn't driving or the car would be burned to the ground

[85crownHPP]

open up the loom and look at the harnes further down... make sure that fues link didnt go....

[89LincolnTWNcar]

I got a 14.6amp electric fan and a 600watt amplifier running on my stock 2G alternator. how long before it explodes? hahah. I worry about it, wondering what I can do to prevent such a fire.

[ss_mini14]

the fusible link was my other suspicion, i found that while inspecting the harness then cussed out a few more engineers. who the hell would hide a fusible link in a wire loom? effing engineers...

[ss_mini14]

i took the car to autozone today and had the alternator tested on the car. they used what looked like an electronic VAT 40. of course it failed and the clerk condemed the harness based on what i told him about the fire. when i got home i checked all the wiring and checked for power and ground on each wire, all checked ok according to the wiring diagrams on autozone's website. tomorrow i'm taking just the alternator to get it tested because i've gotten bad parts from autozone a few times in the past. the fusible link seems ok, it has continuity anyway.

[DarkKnight]

Umm, alot of people will tell you on here not to even buy a Altanator From Auto zone... They prefer Car quest it seems )


And for that very reason. :-P

I myself cant say anything bad about the charging eqipment cause i never bought one from them..

[ss_mini14]

i forgot about carquest. i've had a few bad parts from autozone, a clutch for a datsun that grenaded after 2 weeks, a series of voltage regulatrs for my toyota, a half dozen alternators for another datsun...i could go on for a while. anyway i had the alternator tested today and it failed, suprise! they brought out another alternator, tested it and it was good. what suprised me was there was a new connector zip tied to it which the first alternator didn't have and stapled to that was an orange label that said "DANGER FIRE HAZZARD". what really pisses me off is that i had to go to another store to pay $13 for a new connector when it should have come with the alternator in the first place.

[gadget73]

Normally replacement alts come with that plug. When mine smoked, it wasn't at the plug. Mine went further down, right about the middle of the harness. Interesting (or not so interesting) tidbit, the alternator harness changed multiple times. 1986 has the fuse link over next to the battery. 1987 onward has it between the fender and alternator. Stupidly, the plugs at the fender are different from 1986, 1987, and 1988 and the harness between the fender and alternator will not interchange between those years. I don't know about 1989 onward, only ever tried to replace a burned harness on an 87 with an 86 and an 88 parts car handy. Effing engineers indeed.

[1987cp]

Man, that sucks. That's part of why I tried my hand at making my own alternator harness after I took out the EFI stuff. Admittedly, the big cable to the starter solenoid was "donated" by a nearby factory, but a battery cable wouldn't be harmful in the way of overkill. Anyway, the plugs that connect to the alternator can be had new, and the essential aspects of the wiring are strightforward. Or I suppose you could try a newer used harness ... worst case scenario is that stuff will catch on fire again, right? (Just KIDDING!)

Trying to think ... the 2G I have now is from Murray's Auto Parts, but it replaced a Duralast that didn't have anything wrong with it. That's how I found out the dash light is an essential part of the charging circuitry. I did do some reading about Delco one- and three-wire alternators before deciding it was simplest to make a new harness for my old one.

[gadget73]

I canned my whole harness and did a 3g swap. None of the stock power wiring is in place, just the single wire for the idiot light.

I also found out the idiot light is important, but on my VW. Replaced all the parts to the charging system and it still wouldn't work. My uncle stuck a new light bulb in the speedo and it worked.