12 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHVery brief battery light
Reported or suspected cause
alternator
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
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Reported cause · Original poster
And since we have a new battery, pulley and cable, the only other culprit is the alternator.
Leading evidence: 'alternator' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'alternator' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check /' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
This alternator is still the original with a voltage regulator that was replaced about 5000km ago.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
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Performed · outcome unconfirmed · Original poster
We made sure everything was clean and replaced a couple of grounds that looked suspicious.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
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12 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
We did that with the alternator pulley and that didn't fix anything.
I recently had my Y cable, starter and alternator pulley replaced.
I got the alternator pulley changed because I was experiencing a battery light that would flash at me briefly and disappear.
We thought it was the clutch in the alternator pulley allowing the belt to slip, but since replacing it, it has happened to me twice. every time it happened before swapping the pulley, happened during WOT runs. This morning the battery light flashed at me while I was stopped at a red light, and again while cruising in traffic at 80km/hr.
Triple checked all connections, battery is tight, super tight - its not going anywhere. Ground cables are good.
This alternator is still the original with a voltage regulator that was replaced about 5000km ago.
Any suggestions on what to check next?
I cant catch it soon enough. By the time the dash beeps at me and i notice the warning, its disappeared and the voltage gauge is at 14....or a little over.
That Y cable was definitely needed as the car never went over 14 when running. Now its humming just a tad over 14 like a champ.
You don't mention testing the battery. If your old Alt was really having problems it could have damaged the battery. Get it checked/replaced too.
When is the last time you changed your ignition switch?
Battery is new from last year and was/still is plugged into the Porsche battery maintainer when not in use. i doubt its my battery as all of our volt meter testing for the y cable showed a strong battery.
I've never replaced the ignition switch. never had issues with it either.
The voltmeter test will show a bad Y cable, but isn't a good test for the battery's health. Pull it out and take it to a parts store and have them test it. *Shouldn't* cost you anything other than the time and gas.
If the battery checks out, try swapping that. Really weird stuff happens when it acts up.
No, the volt meter testing also gives you a good idea on battery health. I had to go through all of this 3 years ago when I had the slow battery drainage and trying to source that issue.
I'm done throwing parts at it, guessing if that will fix it. We did that with the alternator pulley and that didn't fix anything.
I'll hook it up to a scanner tonight and see if that will provide me with some insight.
My mechanic is thinking its the alternator itself.
That light only comes on if the system is no longer charging or over charging. And since we have a new battery, pulley and cable, the only other culprit is the alternator.
Dug out the trusty old owners manual to see exactly what it says for the battery warning light. Well, you don't have a broken drive belt, so that leaves "Defect in the battery charging system". If it is not a defect with the battery, that just leaves the alternator/voltage regulator, or the clutch pulley on the alternator. How clean is the engine bay 12V terminal? That is where everything comes together and even a little bit of corrosion there could result in too much resistance. Just throwing it out there....
Very clean.
When I 1st bought the car, I had issues with keeping it charged. We made sure everything was clean and replaced a couple of grounds that looked suspicious. That didn't do anything so we continued on with our investigation and found the brushes on the voltage regulator were pretty much non existent.
We replaced the voltage regulator and that fixed my charging issues. I got a new battery when the car was finally put together last year as the one we bought died while the engine was being built.
I think the only thing left here is the Alternator.
Here is the whole diagram:
http://www.autoatlanta.com/porsche-p...section=902-05
Aside from the alternator (which I agree is your problem), there are two other connection points on the charging system. One is at the power distribution box and one is located under the car. Maybe pull the alternator and have it tested for output, however, since your problem is intermittent that may not reveal anything. Maybe pull the alternator and get it to a shop for a rebuild? Wow, the price of a replacement!
