Engine Braking = Clacking/Popping Sound ++ Generator Warning Light

Howdy,
So when I engine brake and the RPM's are between 2500 and 3500 rpm. At a few select sets, Something is making this clacking/popping sound... I'm
wondering if anyone has any ideas on where I can look?
Also, the Generator Warning light is on... The Battery reads 12.6V when off, and measure 14V when the engine is running idle. Any suggestions on what triggers the light? What can the diagnostic system detect?
Thank you kindly,
-Dinh Bowman-
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The info's a bit vague, but is this the sort of sound that a metal fan would make, hitting the alternator [generator] body a few thousand times a minute?
If so, then the bearings have gone (often as a result of over-tightening, but sometimes plain age).
Look around the front of the unit for shiny metal, to indicate rubbing (it gets dirty down there, so clean metal would probably indicate rubbing)
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the battery is definetely good. im a nissan technician (yeah i know its not audi but electrical is electrical) and a steady volt drop of 12.6 at idle is perfect!! usually 12.4v drop across the battery is what youll find. and youre charging volts are almost perfect as well. 14v-14.4v is what you want. id definetely say something is making contact. however, if the bearings in the altenatore were going/gone, id ont think your charging voltage would be so good, or at least not as steady.
check with a DVOM (voltometre) and see if the charging volts really ar 14v. sometimes thos factory gauges lie a bit. if its below 14v, then id say your alt is on its way out and should be replaced. are you having ANY electrical load issues? like dash lights or headlights are more dim than normal, etc.?
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My 97 A$Q2,8 had a similar problem that was actually an exhaust and intake defect. On an engine brake decel, you could hear a pooping and backfiring sort of noise, but only with the windows down. I chased Audi for 4 months before they admitted a flaw (unfixable). There is/was a service bulletin about it. The voltage meter thing (I think) is a different issue and one I have also seen. Good Luck
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