So sunday night, I was driving home when I noticed my lights were really dim. A quick scan of the gauges showed that my alternator was only putting out about 9 volts. It's no surprise that at the stop sign, the car died. After getting it towed home, I thought for a while and deducted that the alternator was the culprit.

So today I bought and installed a rebuilt alternator from Schmuck's Auto. A 100+ Amp one, which I think is more than stock. (I'm not sure, what did 89 RS 305's come with? I think I read 60?). However, after getting it installed, and jumpstarting the car, it exhibited similar symptoms. That is, it started, ran, read 13 volts, then slowly decreased until it died. Not enough power remained to turn the starter.

My next thought was the battery. However, tests proved negative.

The only idea I have is that Schmucks sold me a faulty alternator? What else should I check before going to the trouble of taking it off again?

Thanks!

~Chris

 

Take the alt (both of them) to a place like Canadian Tire or Autozone and have them tested. I do that a few times a day at CT.

 

Well, for sure the old alternator was going anyway. After taking it off the car, spinning the blade revealed some bearing noise, which I have been hearing the past few weeks.

Besides, they took my old one for a core charge.

So you think it sounds like the "new" alternator?

 

what is your idle speed at? Does the voltage reading fluctuate as you increase load on the engine?

 

I'm idling normally, right around 800 or so. The needle doesn't move too much, but it will increase a little under load.

Interesting side note, when i turn on my blinkers, the needle goes up and down slightly, in time with the blinker. The Tach needle also moves with the blinker.

Thanks for your help

~Chris

 

Get the alternator tested (better to double check now), but I'd start looking at your main ground (pull it and clean it GOOD) and main power at the starter. You may have a connection problem.

 

Ok, had the alternator checked, re-installed it, cleaned all the ground connections, bought a new stainless steel braided ground strap for engine->body connection, and started it up.

For the first few minutes, the gauge was reading low. We got out the multimeter, and it was reading 12 amps at the battery, a tad-low. After letting it idle for several minutes, all of a sudden, the load on the engine audibly changed notes. At that point, the multimeter read 14.7 (as did the gauge inside the car).

What could be causing that? We restarted the car, but it was still warm. I intend to go back out later tonite after it has cooled down to see if it does the same thing.

Thanks!

~Chris