odonnell

Hey guys - been away for a while, my project cars have taken a backseat to work and a fixer-upper house. But I am still tinkering when I have time. Around 2 years ago I ran into a weird issue on my '83 where the engine would stay running after key-off. I traced this back to the alternator exciter wire somehow backfeeding, and keeping the main relay energized (custom relay setup for my standalone, long story, it's triggered by the ignition switch). I put a diode inline with the blue exciter wire and it was fine after that. But obviously that is not dealing with the root cause. So now I am trying to do this properly.

Wanted some feedback on experiences with reman auto parts store alternators, versus reman Bosch, versus anything else available. My understanding is that the auto parts stores (AZ, Oreilly, Advance, etc) options are more than likely coming from the same behind-the-scenes rebuilders and do not enjoy a A+ reputation. At the same time, the current alternator is a reman part from 10+ years ago and was fine up until this incident (or at least I strongly suspect it is culprit). The voltage regulator is serviceable but that is it, without opening it up and doing uncharted surgery.

So in short I am curious on what is tried and true, recently, as perhaps older discussions are not considering the latest reman options, for better or for worse. I am also curious if the Bosch reman part is trustworthy compared to a new Bosch part. In the end I do not want to end up with a crappy situation later because I got a flaky part. I have a new Bosch voltage regulator in hand, which I can swap in - seems to be a direct fit for most of these auto parts reman options.

I am aware of the Quest alternator mod but am not really sure on why that would benefit me, unless the only good options for a direct replacement part are substantially more money. It is a basic street car with low amperage needs and I do not care that much about weight savings at this level.

TIA! Attaching photos of current alternator, P/N 14921, which is offered chiefly by Duralast currently. The pivot bolt was crossthreaded and had to be impacted out. I guess I had never removed it fully in 8 years.

tempest411

I'd go with Bosch myself.

odonnell

Thanks. I bought a Bosch reman unit, p/n AL170X. $155 + $70 core charge...let's hope my unknown unit counts...
It is for a late model but I realized that this is actually correct for my '83 due to the AC delete bracket, as long as I swap the pulley to the one I have just now. Hopefully that is true, anyway. The top pivot bolt is M10 versus M8 for the early 944 version.

Seattle 993

I have an 88 turbo and replaced a good original alternator (that I may refresh - it has 157,000 miles) with a Bosch remanufactured unit because I was doing some other work...it’s performed well. Install with confidence.

Tiger03447

Dear Michael: If you still have the Bosch unit, unless it's been traded in as a core, presumably, one can swap out the brushes and diode pack at the back of the unit with little or no fanfare..Sounds like you might have lost a diode if it's backfeeding. The internal diode pack is not supposed to let that happen AFAIK. If you had your current unit tested prior to purchase, the testing unit (at AZ at least ) would have caught that..unless the AZ parts guy didn't go into the test procedure to find out the real problem. I tested my Bosch unit the other day prior to it's install and it still checked out fine. Brush packs are (were) available through Sorensen or Duralast at AZ last time I checked ..Dorman may also have them. Might be listed on their websites. At a price much, much less than what Pelican lists them for. So, after re-reading your last post, you've already traded in the old one. Hope the new one gives you great service. Good luck!

odonnell

Thanks Rich. On the old alternator the only serviceable part I can see outside the casing is the brush pack / voltage regulator. It accepts the real Bosch part so I am assuming this unit started life as a Bosch alternator but has been rebuilt at least once (most recently by World Class). The brushes were worn down heavily, so I'm sure it enjoyed a long service life, it precedes my ownership of the car.

No diode pack on the outside which was weird to me. In all pictures I can see online there are some other bits on the back. But if you look at the images in the first post, all I have is the voltage regulator and the broken plastic seat for the wire posts (nothing is below it, I checked).

I may have it tested just to see. Otherwise I could be chasing my tail if I remove the diode I temporarily put in the wiring harness, and I get the same issue as before with the engine staying running. I also had a battery drain which I suspect is related.

Tiger03447

Yep!
Definitely sounds like a bad diode. The diodes are there to prevent that battery drain from happening. Otherwise there isn't anything to keep the voltage from going to ground through the alternator. Good luck..

Darwantae951

I run a GM alternator.