• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Help Alt wiring issue

tarafied1

Well-Known Member
I got the car running today, yay! But when I hooked up the battery I heard sizzling and saw smoke at the solenoid. I unhooked the alternator and everything is okay. I was able to start the car.
So is mt Alt fried? I hooked the main harness back to the positive side of the starter relay/solenoid like it was before. I never took the harness off of the alt so it should have been wired correctly. I'm going to double check everything but I was so excited it ran again I had to post a video...
 

tarafied1

Well-Known Member
I unpluged the harness at the connection to the car harness (going to the voltage regulator) so the alternator is completely unhooked. Then I tried putting the connection back on at the solenoid and it still arc welds. So I am guessing something inside the alt is fried. I will pull it off and have it checked at AutoZone
 

Horseplay

I Don't Care. Do you?
Its early so haven't got all the gray cells firing just yet. Am I correct that you didn't make any changes to the wiring or add new parts in the starting/charging systems? It would seem your alternator output was not being regulated and was putting out too high a voltage. The regulator should control that. Unchecked a good alternator could crank of well north of the normal 14 vdc and do what you are describing.
 

tarafied1

Well-Known Member
Ground wire lose ? Did you weld on the car ?
I did weld on the trans tunnel but it was while the engine was out and alt was not in the car, battery was unhooked etc. I also have three ground wires on the engine. one of them is an actual starter cable so it's big.
 

tarafied1

Well-Known Member
Its early so haven't got all the gray cells firing just yet. Am I correct that you didn't make any changes to the wiring or add new parts in the starting/charging systems? It would seem your alternator output was not being regulated and was putting out too high a voltage. The regulator should control that. Unchecked a good alternator could crank of well north of the normal 14 vdc and do what you are describing.
the sparks are flying when I try to hook it up, not running. The power from the battery appears to be going straight to ground as the harness is unplugged.
 

tarafied1

Well-Known Member
with the flat blade part of this harness unplugged, when I try to put the larger round connector on the solenoid sparks fly.
 

Midlife

Well-Known Member
Staff member
Moderator
with the flat blade part of this harness unplugged, when I try to put the larger round connector on the solenoid sparks fly.
That is the ground ring, you dope! True power comes from the alternator through the 3 prong plug, specifically the thick wire in the middle.
 

tarafied1

Well-Known Member
That is the ground ring, you dope! True power comes from the alternator through the 3 prong plug, specifically the thick wire in the middle.
well that would explain that! so where do I ground it? the engine? I really can't recall where it was located. I must be getting old...
 

Midlife

Well-Known Member
Staff member
Moderator
OMG...yes, the engine block! Ground has two rings: the small one on the alternator, the big one on the engine block, and another through the alternator plug.
 

tarafied1

Well-Known Member
OMG...yes, the engine block! Ground has two rings: the small one on the alternator, the big one on the engine block, and another through the alternator plug.
thanks, for some reason I was thinking that big one went on the solenoid. THANKS for checking my shorts
 

tarafied1

Well-Known Member
Mid's a mite cranky today isn't he?
I deserved a rash response. I screwed up by not taking a pic or making notes or just plain not remembering. I did pull the engine out about a year ago so it’s been a long road.


Sent from my iPhone using Tapatalk
 

Midlife

Well-Known Member
Staff member
Moderator
Mid's a mite cranky today isn't he?
Get off my lawn, you punk!

Yeah, I get cranky whenever folks do things they should not do, particularly when it is real obvious what is wrong. All Craig had to do was to wonder why the thick wire went from the alternator BAT terminal to the alternator plug instead of the large ring connector with two small wires. You need a thick wire from the alternator to the battery to handle all of that current. And why would one have 2 wires on a battery solenoid post ring connector and where could they possibly go to? Hmmm...
 

Horseplay

I Don't Care. Do you?
And why would one have 2 wires on a battery solenoid post ring connector and where could they possibly go to? Hmmm...
I can think of reasons. Aftermarket connection for anything that needs full time power source under the hood, for example. Come on, you asked for this after your "should know better" comment!

Many people are so intimidated by electrical they turn into "deer in the headlights" when faced with even a basic electrical issue. At least Craig knew to ask for help and eventually posted a pic to help understand what he had in front of him. Be nice.
 

tarafied1

Well-Known Member
My logic was that the harness went to the voltage regulator and there fire the alternator needed power from the solenoid. The alternator is very hard to see. It’s under the engine.



Sent from my iPhone using Tapatalk
 

Midlife

Well-Known Member
Staff member
Moderator
Craig: if I were you, I'd stick with aluminum as your primary source of income; leave the Smoke Jeannie to us magicians.

At least you did the smart thing and unhooked the alternator before proceeding.
 
Top