Deb

I am looking for the sites that have alternator diagnosis but don't recall whose sites they are, a search doesn't come up with one - anyone direct me?.
Initially, on reinstall all of the lights on the pod came up including the (!), in spite of that condition all of the gauges read normal. Also, after starting the Amp meter gauge read low - down near bottom of scale but if I blipped (scientific terminology) the accelerator it would immediately run up onto the normal scale. As of yesterday it isn't charging at all?

Sean79 5spd

Deb, I had the same symptoms on a rebuilt alternator. Fortunately, the supplier will replace it.

Using a volt meter (not the volt meter in the car), you should get about 13.8 V at the jump post in the engine bay with a fully charged battery and no accessories on. Or better yet test on the output terminal of the alternator.

Also check the belt tightness.

Sean

Drewster67

Did your battery have a full charge before you reinstalled the alternator?.

Recharge the battery, and try again. It may be a weak or possibly bad battery.

Sorry, no info on the sites.

Good Luck

User 4221

Deb,

Look at the conditions:
You changed a no-charge alternator with another and it worked fine for a while.

An alternator works on basic electric principals of converting mechanical energy to electrical energy by moving a magnet through an electric field.

In the case of our alternators, the magnet I believe, is an electro-magnet that is driven by the excitation ckt.

To charge you need:
Mechanical rotation
Field Excitation
A load with no short circuit

Before you pull the alternator, measure the voltage at the smaller connector or "-" connector on the alternator when running and charging.

If you do not have approx. 12V at this terminal when running, you either have a shorted field in the alternator, a shorted wire in the harness or the an open circuit in between the pod and alternator.

The final option is another bad alternator. It is possible.

HTH,
Scott

User 4221

One final thing.... Your harness between the alternator and 14 pin connector on the pass. fender may be corroded badly enough and creating a dynamic open ckt. condition between the alternator and 14 pin connector.

Like mine was: https://rennlist.com/forums/showthre...ight=christmas


HTH,
Scott

Randy V

Hey Deb, I see you are in Picton, Ont.

I'm from Sault Ste. Marie, Ont. I'll be back there next week to visit my folks.

re. your alternator, sounds like either you installed it incorrectly, or it was a bad rebuild.

Pull it and have the rebuild shop test it and rebuild it right if necessary.

Deb

Hokay!!
-Don't know ho I could have installed the alt. incorrectly except for the two wires - large Red + to the large + term. - small (blue or green) to the (-) terminal and not to the Grd. terminal, I belive that the ground is actually made by the body of the alt. in contact with the attachment points on the block.
The batt. is 4 months old and was charged to 13.0 vlts from a charger prior to hooking up the rebuilt alt. Batt. at rest for 20 mins following above charge read 12.55 vlts and read 11.95 at idle. Checked the 14 pin connector on the fender and the wires/insulation are totally clean and bright finish / the pins are actually a shiny pewter colour with no evidence of dirt/corrision.
This car has less than 40k miles and has never been out in rain/snow/sleet/seaweed so every thing is quite clean. The alt. belt is new as of 1 yr and 3k kilometers ago and is set to spec for tightness. My last check before returning to the rebuilder is the voltage at neg. term. engine in idle. Thanks for all of the input it's all very valuable info. Randy, re: Sault Ste. Marie - I used to visit there about 4 times per year as the Kodak Medical X-ray Rep., called on the Plummer Mem Hosp. and infact got the business from DuPont who had previously had the account for about 23 consecutive years -- How Sweet It Was!!!

John Struthers

Deb,
FWIW
I normally follow the sage advise of the Guru's but on the the subject of rebuilds ....
There was an old rule of thumb to rebuild the alt that failed.
If for no other reason than the cooling duct/cover was sure to fit after install. There were are 3 manufacturers -Paris Rhone, Bosche, the third slips my mind, I think the Paris Rhone is the ugliest alt I ever met-.
The other rule of thumb was that if you go to Auto Zone, Advance, O'Rielly's ... you would have to try three alt's. to get one that worked and there was little or no hope of recieving one that the Air duct/cover would attach to.
The Guru's also recommend that you find a competent, full service, rebuild/automotive electric shop.
In my case the best shop in town -they even have a full set of manuals for the 928- can repair WW II war Bird electricals, Including starters, generators, also do WW II armored and wheeled vehicles of both German and American Manufacter.
Any kind of car with the exception of Citroen's and -you guessed it the 928-.
He say's the 928's were fine cars right up till when the owner starts messing with alarms and electicals in general.
He lost his butt in manhours because owners blamed him for all sorts of electrical quirks, wonder why they came to a shop in the first place? His shop is always busy and he supports 5 other spark chasers, a secretary and a book keeper. He flat refuses to work on the 928's or modified 924/944 series Porsches.
There are two other shops whose work leaves much to be desired (you can guess but, don't ask).
All I can recommend is that you be present after any rebuild for the load test.
If you buy one from an Auto Parts store have them test it in front of you before you walk out of the store.
If you can, get the alt with the rectangular rather than round -button type- regulator. I have yet to install one with the button type regulator that worked for more than a few day's.
Button type and rectangular type are interchangeable.

jim morehouse

Deb,
Here's the link to the alternator test procedure:

http://www.nichols.nu/tip692.htm

Jim

Deb

Thanks Jim! Well I had the alternator bench tested while I watched and it performed perfectly so to-morrow I'll go with the testing you provided.