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Discussion Starter #1
Yesterday, for three startups in a row my 02 1.8T displayed the battery warning light immediately on startup and then seconds later the text display read "ALTERNATOR WORKSHOP!".

Now, I assume that the Germans wrote this message. And based on my experience with these German engineers thus far, they are not one to throw around exclamation marks idly, so naturally i pooped my pants a little. However, the warnings - both battery and alternator - went away after a minute of driving. *phew*... (i think?)

But then, it comes back! But only right at starup, and only for a minute. And not on every startup....

This morning my german-car-specializing-mechanic concluded that the alternator was in fact fine. He gave the battery the volt-meter test and the alternator was churning out a most admirable 13.9 volts of juice. Whats more the belts are tight. So... i am left wondering, what could this be?

Someone along the way suggested a voltage regulator issue?
Could it be a sad battery?
How does one test the sadness of a battery?

As always, thanks in advance for your guidance!
 

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Discussion Starter #4
Really? But the alternator is putting out 13.9 volts at idle when measured at the battery.

Also, just now, the car starts. Battery light. Workshop warning message. Fine, ignore... drive... then... ABS light, Traction light, AIRBAG LIGHT!!! Dammit, i know what this means... turn off all stereo/heating/etc. hope to get a couple more kilometers, and then...*bing*... everything is fine, all warnings dropped. Keep driving. After a few minutes try turning a few things on again. Eventually turn on all heating/stereo/etc.... no prob. Keep driving for another 15 KM, no problem. WTF?!?!
 

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13.9 volts doesn't mean squat with an alternator. The alterntor's job is to make amperage, charge your battery and run any electrical equipment while the engine is running. 13.9v okay, but it could be putting out 40amps or 0 even..
 

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Discussion Starter #6
Well then how do i test the ampreage output of the Alternator?

Also, how do we explain the sudden disappearance of the symptoms? Is THAT normal? Cause that seems quite peculiar.
 

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Any shop should be able to perform an alternator / starter / battery test. It can't really be done properly with just a digital multi meter unfortunately.

I'm not sure, but maybe a parts store like Advanced auto parts could have a starting and charging system tester?

These tests can usually pinpoint or get you in the right direction to finding the problem for you.
 

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Discussion Starter #8
Alright, looks like it is time to bug my mechanic again. See what he can do.

Up here in friendly Canada we don't have either autozone or advanced, and none of the parts places do free diagnostics, that I know of. Anyone else know different?

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Could be a ground issue, too. Especially with the weather change. Gets cold in the driveway...ground becomes flakey. Engine/engine compartment becomes warm...everything expands and works fine.

AJ
 

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Discussion Starter #10
Battery light was on this morning and stayed on until I got to the mechanics. He plugged in the diagnostic laptop, and yeah, only 10 volts. Alternator not happy.

So looks like 600 bucks of fun for my by the end of tomorrow!!! Yay! Arnt cars great!!!

Though the intermittence of it makes me wonder about ground connection. I'll ask him to have a look.


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Discussion Starter #12
Sadly, the car is undriveable at the moment. And I need to get around for work. So if I was to order the part, it would take a week to get here, and then I need to take a day to install it myself.

So that would be over a week of replacement vehicle rental, which pretty much eliminates any benefit right away.

With less critical systems I would totally be doing it myself, for sure.


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My alternator died on the highway, I pulled over called a buddy and got him to pick up my tools from my house, jump me and I made it to the wal mart parking lot.

We went to the local parts yard, picked up an alternator and I swapped it right there in the parking lot and after another boost was on my way.

You can do this yourself!
 

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Discussion Starter #14
I will grant that it is not a particularly huge job, but I don't have the time to deal with this is all. I can't afford to be carless much longer.

But now you've got me thinkin'... Damn you!!!
 

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its not a huge job on a 1.8T, tho a bit of a PITA. it is a huge PITA job on the V6 - a "set aside one whole day" job.
 

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Heh. $85-$125 from a couple of local yards, Nick. Although it is nice to buy new and just get it put in. Sounds a bit steep, though. Who's your mechanic?

And yeah, I was going to say that testing the alternator after the fact wouldn't show you anything. Testing it right after startup, with all the lights going off, would be what you'd want to do. Canadian Tire tests batteries and alternators for free, but you have to bring them in 'out of the car'.

Dehrslacidar, you're technically correct, but the way it usually goes is that if you voltage test your electrical system and it shows 10-11v or less, then your alternator isn't working. Anything 13 or over? The alternator's charging. You can tell because of the voltage boost on the battery. However, it doesn't show HOW much it is or isn't working. To answer the question on how to test, you'd have to put your meter in-line with the system, which is a bit tricky. ESPECIALLY when you consider how much current is flowing when the car's running. My recommendation is DON'T DO IT... ;)
 

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Discussion Starter #18
The mechanic is a performance shop owner that specializes in German cars. I have already left it with him. I think I will call to see about getting a scrap yard piece put in.

Thanks for your help guys.
 

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Alright, looks like it is time to bug my mechanic again. See what he can do.

Up here in friendly Canada we don't have either autozone or advanced, and none of the parts places do free diagnostics, that I know of. Anyone else know different?

Sent from my Autoguide iPhone app
I would get your battery checked at Canadian Tire.
 
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