v8miata

Hi everyone!


New here. For all pretense and purposes this is a 1994 5.0L Mustang GT. Just sitting inside a 1994 Mazda Miata body.






The wire connector to the alternator melted on me while driving. It got so hot, it melted the solder on the connector pins of the alternator also.


I am reading that it could be either an internal short on the alternator, or I have bad/insufficient grounds from motor to body.





My big question, after I clipped the connector off, on the red and blue arrows in the photo above, I am getting +12v power to each of them to ground all the time (key out of ignition, etc). Is this correct or do I have another short somewhere?


Thanks!

v8miata

http://s13.postimg.org/whhrkw7tj/image.jpg
http://s16.postimg.org/ielhvzi51/image.jpg
http://s10.postimg.org/hlwqeyvp5/alternator_plug.jpg

64bit

Looks more like a 93 and older...

Better pics of the engine are needed, so I can grab the right diagram.

v8miata

hmmmm... interesting. The SMOG sticker says a 1994 5.0L. Guy who sold it said it is actually a '93.


I will get some better pics including the engine number if that helps.

dawson1112

It defiantly has the 93 style intake and the 93 and earlier style belt tensioner on it. But it looks like a 3g alternator was installed on it.

v8miata

That helps a lot! It is a 3g alternator. So which model years (and possibly other makes) is this found in?

This car may be a bit of a frankenstein... but it WAS professionally built by a shop.

The picture shows the plug that melted...it is around the side of the alternator, there is a 2nd plug that plugs into the top for the exciter I believe, it is a 3 wire plug also, but small gauge. This plug below is what delivers the power to the battery.

Melted Plug...

What situation am I in regarding finding a replacement plug, is it cut one out from a different harness and solder/crimp it back into mine or is it a cable (with plugs on each end) that I can buy and replace from the auto parts store?

dawson1112

I may have been wrong it might be a 2g alt. Does it look like this?

This is a 2g alt from a 93 mustang

dawson1112

If you go to auto zone it will show you all the cars with that same alternator , there are over 170 different cars/trucks/vans that use the same plug. Should be able to find one at any junk yard.


http://www.autozone.com/batteries-st...?checkfit=true

v8miata

Thanks all!

Got it all figured out (all of the reading is all making sense now).

This is a 2G Ford alternator, which probably should be upgraded to a 3G alternator that uses a big single cable secured under a nut to deliver the power instead of these dinky cables in a plastic shell.

At least, that is what I am gathering at this point. Got a new connector ordered up, probably going to grab a junk yard alternator to see if the problem is truly resolved (and its not a grounding issue like I have read others have had and ended up burning out multiple alternators).

So the "official" diagnosis (from the guy who built the car), these connectors oxidize/corrode over time increasing resistance, where resistance increases so does heat. The heat got bad enough to melt this.

Anyway, some more pics








Thanks again, only owned the car 3 days now, already miss driving it, it is totally insane... ~2600 lbs (might be less-- 2400lbs possibly) and 275-295hp 300ft/lbs torque. Just a rocketship in any gear.

v8miata

yes! thanks, got it sorted out before reading your message, a picture surely does say 1000 words and it was that exact picture from autozone that clarified things for me.