Issues with 3rd cooked alternator in 5 years...
 

As usual, the alternator s#its the bed, 20 miles out, in the dark.

So, I drive it home with the lights off and as few accessories on as I can...

I've not added any additional lighting, nor changed out the sound system, so I can't see that I have any extra strain on the system that would be taxing the stock spec. alternator...

Then I got to thinking... I have the Hypertech Thermal-Master chip in the ECM. This prom requires a 160° thermostat, and the chip keeps the radiator cooling fan running ALL the time. I now figure that this is most likely my culprit...

Now, my next question should be in the PROM section, but I figure I'll let the trusty V6 guys have at it first...

Can I data table in the prom that enables the fan to be constantly on, and instead set it for maybe 170° or 180° instead?

Thanks! (Again...)

I had always thought that the fan wasn't computer controlled, (but the way I've been posting lately, I'm probably wrong :rolleyes: :) ) but instead controlled by a separate temp sensor and switch on the engine.

Where have you been getting your alternators, and what kind of amp rating are they?

Logic tells me that the initial amp strain to start the fan wouldn't be enough to destroy an alternator, or even put that much extra wear on it.

If the fan is computer contolled, then yes you can go in to the PROM and change it, but I don't know if you can with a hypertech chip, you may have to burn another one completely. Hope that helps you out some.

85-86 alternators commonly burn up the rear bearing... I'm on my fourth or fifth one. Gotta love the Pep Boys lifetime warranty... if only they'd stop changing the damned part # on me!

Tom, was the rear bearing problem noticed on only 85-86 model years? I'm just wondering because my '90 alternator did that when I first got it.

Not too sure (don't have an 87-92)... I asked a long time ago on the tech board if anyone changed their 85-86 style to the improved 87-92 style. Most people responded saying the 87-92 style sucked too!! Lets see if I can find that message...

Cool, found it. My memory's poor though, because not as many people wrote message in it as I thought. But here it is: https://www.thirdgen.org/techbb2/sho...hreadid=121021 Maybe someone could ask again over there? :)

Problem is, putting 87-92 on 85-86 would require newer brackets. Can't use the 87-92 brackets on 85-86 because the 87-92 alternator bolts to the tensioner (serpentine belt). I guess something would have to be fabricated.

Okay, just made a new post about it: https://www.thirdgen.org/techbb2/sho...hreadid=183628 Lets see what happens. :)

When you put the new alternator in what did the gauge read? The problem may not be with the alternator but one of the fusible links by the starter. One of them is the voltage feedback to the alternator. If it goes the alternator will either put out full power and burn itself out, or nothing at all.