audifirst

I haven't drive my car for week and half, I was away on training, when I came back , when car idles I notice that lights dim, when rpm drops at the same time, and battery gauge moves as well, the problem goes away when I apply gas pedal or drive, what procedure should I check for to eliminate possible faults,
last year did major TB and replaced the alternator with rebuild one, I haven't replaced battery at that time, just recharged it, I am hoping that alternator is not a problem,

Kris Hansen

The SAI pump kicking on will do what you describe.. Does the batter light come on at any point?

Rob KM.

Battery weak or failing.

basso

Re: what volt is it showing in the dash ?

audifirst

at idle it needle moves from 12.5 to 14.2 v, when driving close to 16 volts

audifirst

battery light didn't light up yet

audifirst

when car is at idle, the voltage on battery moves from 13.1 to 14.5 continuously,

frankinstyn

<center><img src="http://www.autohausaz.com/secure/PartImages/1197311530.jpg"></center><p>
This is a classic case of your voltage regulator either dying. First go and double check all the connections but these really are the common symptoms.


Your alternator probably has a lifetime warrantee (most do) or you can simply swap out the regulator. I saw you had the eurospec avant but had to guess as to the engine (eurospecs had other options available). Here is the part for the v6 2.8 engine.

This does not have anything to do with your battery except that it will fry the battery and many systems in the car if you run it like this too much.

You can double check that the readings on the dash are correct before you start buying parts though. Leave the car idling and put your voltmeter across the terminals of the battery. The charging voltage should be between 12.8V and 14.7V It should never waver as you describe and should never go above 14.7V

Here is a site that does a very good job explaining the system.

http://www.familycar.com/Classroom/charging.htm<ul><li><a href="http://www.autohausaz.com/search/product.aspx?sid=2jbzcpavvgibf24525ljn4ab&amp;make id=800002@Audi&amp;modelid=1352506@A4%20QUATTRO%20 AVANT&amp;year=1999&amp;cid=18@Electrical%20%26%20 Vacuum&amp;gid=4884@Voltage%20Regulator">autohausa

audifirst

First video shows voltage changes , and you can notice dimming light on mileage display
<a href="http://img532.imageshack.us/my.php?image=movieke0.flv"><img src="http://img532.imageshack.us/img532/3040/movieke0.flv.th.jpg" /></a>

Second shows the rpm changes at idle

<a href="http://img532.imageshack.us/my.php?image=movie0001mw2.flv"><img src="http://img532.imageshack.us/img532/7676/movie0001mw2.flv.th.jpg" /></a>

the third video show engine noise hard to hear the rpm changes

<a href="http://img532.imageshack.us/my.php?image=movie0002vg4.flv"><img src="http://img532.imageshack.us/img532/3488/movie0002vg4.flv.th.jpg" /></a>

audifirst

hopefully the place I bought from, will be kind to me and will sent me new voltage regulator, as oppose changing entire alternator