LP928

I took off my alternator and brought it to advance auto. They said it was only producing about 11-12 amps. So I assume I need a new alternator. $170 from 928 specialists the best way to go?

86'928S MeteorGrey

The alternator went out on my daughters 944 a while back. I found a local shop in the LA area that rebuilds and sells alternators on ebay. The place is called "BNR Alternators and Starters" I got a 115 amp bosch alternator for $110 from them. It has been doing great for about 18 months now. When I picked up in person the alternator, I asked them if they wanted my core. They said yes and gave me $40 for it! $70 for a nice rebuilt Bosch can't be beat IMHO....
It seems though that with shipping, you are still looking at about $160 unless they will take your core.

Their store:

http://stores.shop.ebay.com/BNR-PART...__W0QQ_armrsZ1

A listing for a 928 alt:

http://cgi.ebay.com/ebaymotors/Porsc...Q5fAccessories

Good luck! Be sure and charge your battery fully before running with a new alternator.

Alan

Bill most alternators will self excite at high RPM - but not all. The only reason this works is that some residual magnetism builds up in the rotor and this causes some generation even when there is no rotor current. In a brand new alternator, or one with a new rotor, this may not work and in fact some brands build up less effective residual magnetism due to their design. So while this is effect is common - you cannot rely on it diagnostically.

Alan

LP928

Sorry, my cars a 79 I forgot to mention.

Does this seem like a good deal, good quality:http://cgi.ebay.com/ebaymotors/Porsc...Q5fAccessories

Is it as good or the same as the 928 specialists one?

RicerSchnitzzle

The negative battery cable connect behind the removable rear cover where the tool set is. The "Ground Starp" runs from the frame to the bottom of the engine block. Both should be very tight with clean contact surfaces. Also make sure you jumper post bolt is tight. Though not too tight as they plastic framing is prone to breaking if you really wrench down on it.

As said above, if your charging lamp does not turn on when you first turn the key, the exciter circuit is broke. Might need a new bulb or have a short in the wire. Make sure exciter wire is securely tightened down on the smallest post of the alternator.

As a cheat, you can run a small bulb in line on a wire taping off the coil positive terminal to the exciter post on the alternator. You won't see the light inside the car, but will still achieve the same effect with out taking the pod apart.

Also take your alternator to another shop to spin it before replacing. No offense meant to anyone, but the $8 an hour guy behind the counter can make a mistake now and then. My ex-wife ran PepBoys for a few years and had to put some real inexperienced guys behind the counter. She couldn' afford to pay the good ones. When the new ones got experience, they moved on for more money.

LP928

I'd like to take somewhere for more testing, but Lake Placid doesn't have much to offer... maybe Sebring will. I also will try to look into the exciter circuit.

Sailmed

I'm off on Tuesday and Lake Placid is a very short drive...
If you want someone to take a look at the car for you, it's no problem. In fact I haven't seen George in Sebring in awhile and wouldn't mind a road trip.
Not that I know anything about 928's tho...
I'm just a man of many tools and a little bit of knowledge - which can be a dangerous thing.....

LP928

That would be great. I'm 16 and this is my first car, first car I've ever worked on also. By the way, who has a gold 928 in the lake placid sebring area? I've noticed it a few times , while I was driving my mom's mini van, You can imagine how pissed I was not driving my car.

Sailmed

I've heard of ya, I think it's great that you have the car and actually work on it. I'm not going to get dirty working on your car - I'll just provide a good volt/amp meter, some good tools, and a little guidance - you get to do all the work.
It has been my experience that teaching this way, you learn more, and I don't get dirty.

LP928

Sounds good to me basically I'm forced to work on my car I don't want to pay a local mechanic who knows about as much as me on 928s. And its fun.

Lizard928

Well Alan having it checked at the shop proves that it is not an exciter problem. But that is a good point to know. Though I have yet to see one on the 928 that wont.

Now if you arent willing to read and if you dont understand what they are saying to ask more questions, then yes spending that $170 or so to buy a new Alt is your best way to go.

But if you go back and read my last post you may save a couple bucks......

LP928

OK I will try to find a shop to check the diodes before I order a new alternator, but would a shop charge to check an alternator? If so it may be cheaper to go with the ebay alternator :http://cgi.ebay.com/ebaymotors/Porsc...Q5fAccessories

Lizard928

If it was making some voltage it is most likely that the diodes are ok. And I have only seen one fail, and I just snipped the wire on it and continued to use it for a long time without any problems.

Consider even just replacing the voltage reg. They are around $15-$30 and then test it.

stolarzj

I just replaced the voltage regulator on my original from 86 alternator. I brought it into a Bosch shop to have it checked figuring with the age of the alternator it was time for a rebuild. They popped in a new Bosch regulator and its now putting out 14 volts and 120 amps. It was previously only pushing out about 12 volts.

GlenL

For Bosch alternators you can get the regulator and brush assembly cheap and do it yourself.

http://www.drivewire.com/vehicle/por...age-regulator/

Simple to do once the alternator is off.