[Biturbos4] Brewing electrical problem?

Long, Scott G A1C USAF AFMC 88 SFS/S4W Scott.Long2 at WPAFB.AF.MIL
Tue Jan 20 05:47:13 PST 2009

Probably the alternator getting weak.  Modern alternators have built in
voltage regulators.

Scott G. Long, A1C, USAF 
Client Support Administrator 
88th Security Forces Squadron 

-----Original Message-----
From: biturbos4-bounces at diablo.audifans.com
[mailto:biturbos4-bounces at diablo.audifans.com] On Behalf Of Chris
Sent: Monday, January 19, 2009 8:04 AM
To: Bi-Turbo Audi S4 Audi Fan Group
Subject: [Biturbos4] Brewing electrical problem?

The voltmeter has acquired a new behavior in the last few days that I
suspect is foretelling some electrical issue in my near future...

Cold start : Turn key "on" : almost 12v -- about normal given ambient
temps around 20degF
Start engine : cranks normally
Engine running : ~14v on the gauge -- this seems normal
Voltage stabilizes around 13.5v -- normal, too
After ~10 minutes : voltmeter gradually starts dropping from ~13.5v --
uh oh
After ~20 minutes : voltmeter barely at 12v when RPMs > idle
Barely ~11v at idle -- yikes!

Turning off all electrical consumers results in a slight up-tick, but
still under 12v.

No other signs of trouble (e.g. battery warning light, etc.). Engine
still seems to crank normally.

I suspect that something is about to let go, but what? Battery?
Voltage regulator (is this separate or built-in to the alternator)?

2001.5 S4 Avant 6spd
Biturbos4 mailing list
Biturbos4 at www.audifans.com

More information about the Biturbos4 mailing list