Need help IDing my alternator ASAP. It's either gone bad or is insufficient. It's a GM style alternator but I have no idea what it's supposed to put out. I'm going to pull it out and replace it, but I don't know if I should get the same one, or if I need a higher output one. I found a receipt in the truck for an alternator but it says it's for a 1984 Chevy Celebrity 4cyl - is that a common swap/upgrade? Sorry about the crappy pics. Please help.

 

It's hard to tell from the picture. How many wires does it have? It may be a GM one wire. If it is I would suggest changing to a three wire. A lot of people use the one wire because its easy but that thing is no more then a battery charger, they are fine if you have something like a tractor that has no high electrical demand. If you have accessories and headlights etc they just can't keep up. I have one on my ranchero because the PO put it on but I will soon be changing it. Now all the one wire people will start throwing rocks at me because they don't have a clue..

 

Yeah I'm noticing that. On long drives it seems fine, but in my 7 mile stop-and-go commute the battery doesn't keep a charge.

 

Catalog. Take some time and read through this site and it will explain it.

 

Personally, I'd get rid of it. A lot of people use them because of the one wire hook up. Get a 3G Ford, much superior and it only takes 2 wires. Most of them will put out at least 95 amps and do most of that at idle.

 

What else needs to change to go to a 2 or 3 wire? I'm reading that MAD Enterprises thing now...

I'd like to slap one in and get back to driving my truck, versus have a bunch of down time.

 

As Willowbilly said a Ford two wire is the way to go, I may go that route. The link I gave you was just so you can see the difference between either the GM 3 wire or the Ford compared to the one wire. Also I believe the Ford 3G is cheaper then the GM.

 

https://www.ford-trucks.com/forums/9...g-upgrade.html

 

Look for them on V6 cars. I think most of the mid 90s V6 Taurus used them, some mustangs and Econolines. Many other applications too but they bolt down solid and have the wrong mounting. I get them for $10 if I pull them myself, $20 if they pull them. They are far superior in every way to any Delco and really how smart do you have to be to just run one more wire from a key on source.

 

Turns out I'm an idiot. I went to pull the alternator last night and as I did I noticed the ring terminal for the main wire was about 99.99% broken. It actually broke when I touched the wrench to it while taking the nut off. Also, the signal connector was melted and not making good contact. Rebuilt the harness last night and I'm putting it in today. Can't imagine I'll have any more problems after that.

It's a 65A alternator, and I figure the battery was probably getting less than 5A the way it was, so 65 should be plenty!