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Hello,

Yes, another alternator thread. I have been unable to find an existing thread with an issue similar to mine. I have a 1983 Celica Supra and have had to replace my alternator 5 different times in my 3 years owning the car. They have been remanufactured alternators. The most recent one being a Bosch Reman ALX311, this one lasted 2 weeks in the car and just failed on me. I know this is not normal operation for alternators.

I know that there is something that is killing all these alternators. I don't know where to begin to look. I have checked all fuses, I've done the RadioShack diode "charge-light mod fix." I bought what I thought was a premium brand alternator for my Supra a few weeks ago and it is already dead. My question to the experts of Celica Supra's, is there something I should be looking for that could be sending positive charge BACK to the alternator? I am lost. I am going to start looking at wiring diagrams because I don't know what could be killing ALL these alternators.

I have ground from the negative battery terminal to the chassis and one separately to the engine. I think the odds of so many alternators are so slim to none. The common thread seems to be that they go bad on long trips >150 miles. Are 65 amp alts notorious for not withstanding heat?

Please, any direction would be greatly appreciated.

Mods, let me know if I need to edit this post.
 

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I would suggest picking up a Denso rebuilt alternator. A lot of the rebuilt stuff in the parts store is cheap crap with a new coat of paint. Last I looked the Mk2 one wasn't available from Denso so you might have to upgrade to the newer ones you can retrofit. The factory stuff is plenty reliable if everything is in good shape. You can check the condition of the main charge wire since they tend to corrode on any car.
 

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Get your battery tested and get a load test done on the battery ground and charge cables. Probably a big voltage drop between the battery and alternator means the alternator is working overtime to get the full 14V on the sense wire at battery positive.
 

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Good advice already. Yes, well known that all the auto parts stores do to "reman" an alternator is test it, replace the one part that's broken, clean it up and resell it. It's still a 35 year old alternator but they just replaced one diode. They can even offer those "lifetime" warranties on some reman'd parts because the parts are typically being installed on "beaters" with already high miles and thus statistically, the repaired part is very likely to outlast the rest of the "beater" or at least last longer than the current owner would typically hold onto it. Very few of these reman'd parts are being installed on a classic car or enthusiast-owned car with expectations that it last for another 30 years. With electrical parts like alternators and starters, if I can't buy brand new, I always take them to a local rebuilder that I trust where I know they will replace every component that can possibly wear out. They will also restore them cosmetically if I ask, like re-plating the fans, pulleys and fasteners for an OEM appearance. Its generally cheaper than the cheapest budget part from the local auto store but the only downside is that I usually have to wait a week or two. You've probably got a shop like that near you.

Also two things more to check: 1) Make doubly sure that the power steering pump is not leaking. Well known that dripping power steering fluid onto the alternator will kill it. 2) Make sure that your engine undercover is in place and intact. Alternator sits low in these cars. So many of these Supras have lost their engine undercover, they get cracked or broken and somebody doesn't bother to mend it. Well known that a big splash will short something out, but even little splashes accelerate corrosion on internal connections.
 
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You can check for a parasitic draw on the system, also. Disconnect either battery terminal.(You will loose your radio pre sets).Put a test light between the terminal and the cable KEY OFF, door closed. IF the test lights lights, you a have a current draw. If not, look elsewhere.

Good point on the PS fluid getting into the alternator! Thanks, Phil.
I use a 2 A. battery maintainer. Onboard. Keeps the battery happy. I have seen low-end batteries last 10 years that have that trickle charger installed. :oops: Less work for the alternator, too.
These are cool:
 

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One thing about the stock alternator which is quirky (IMO) is that if you have a bad/really low battery (and get your car started) it sometimes kills your alternator immediately. I am guessing it is due to the excess power draw on it? But I would recommend going the Camry alternator upgrade route. I have at least not killed mine when I ran the car with a really low battery, so maybe it is a better solution to that issue.
 
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