North American Turbocoupe Organization

Full Version: 3g alternator hot !
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I have a 1987 Turbo Coupe that I did the 3g alternator upgrade by following the tech article from Jeff Korn ,it has worked perfect for years. The other day I was in the garage after running the car and I smelt Electronics burning so I open the hood and the alt was very hot, and the 10 gauge wires coming off of it, the first couple of inches were melted. I read multiple articles and threads, and I came to the conclusion that the alternator was not working properly ,being it was a junkyard piece to start with I bit the bullet and bought a brand new one. I did upgraded the wires to 6 gauge and added a ground to the alternator. It charges fine and wires are cool, but alt still gets hot in 1or2 min of run time. I would like to know if this is normal?? Any help would be appreciated. Thx, Jeff.
Not normal. Even under max load (lights on, defroster on, blower motor on high, etc), the 10 ga wires on my TC never even get warm.

Sounds like there is something drawing a lot of amps from the alternator. This would also cause the alt to get very hot. I would start by getting a hold of a Hall effect DC clamp on ammeter and see how may amps the alt is putting out.

What is the system voltage measured at the battery when the engine is at 2000 RPM?
Hey Jeff, thanks for the reply . I will try to get the voltage that you're asking for Asap, I'll have to see if I can borrow an amp gauge with a clamp on it.
Hey Jeff, I did have time to check the batt voltage at 2000 rpm It was 14.53. I disconnected my radio amps, msd ,electric fans , and meth, it did help but was still warm. I then reconnected the cooling fans and it got really hot very quickly. I will try to borrow a amp clamp from an electrician at work tomorrow. Thx again for your help.
Hey Jeff, I got an amp clamp and with all the above disconnected the apt is still producing 113 amps at idle. It looks like I got some digging to do. I will dig into it on the weekend. If anyone has any thoughts, please let me know. The, Jeff.
What’s your battery voltage with the car off, no accessories?

It appears to be about 12.56, I have been disconnecting the batt from the system when I am gone just in case, at least until I get the problem fixed.
Wow! 113 A...... You have something drawing a huge load from the alternator. I am surprised your wiring harness hasnt gone up in smoke. Must be a near dead short to ground in the alt output circuit.
OK, so I am thinking the short would have to under the hood.....wouldn't anything in the car pop a fuse??
That would be my guess.
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