weak alternator

Brett Dikeman brett at cloud9.net
Fri Apr 5 11:02:33 EST 2002

At 11:31 PM -0800 4/4/02, Shayne wrote:

>I think the stock amp is 130 amps.

110, and it's possible someone dropped in a 90 by mistake.

>   Even if it is only 100 amps, that should be more then enough.

It's enough.  Not "more than enough" by any means.

>Check for loose connections and bad connections.  You should have WAY more
>then enough power.

It's exactly the opposite...the alternator barely meets the needs of
the car when the big accessories kick in(like the fan.)  By the time
you get through with the blower motor&climate control unit,
ECU(remember, that includes the O2 sensor heater, and every single
valve and sensor!), ABS controller, headlights, rear defogger,
radiator fan, all the dash and switch lights, etc...you're talking
about a lot of juice.  Now you're adding big audio amps? :-)

>Avi's high zoot alternators:   http://home.pacbell.net/avim/index.html

I don't particularly recommend them.  Avi was pleasant enough to deal
with and was willing to help me out in a crunch, but he never really
could explain why I saw absolutely no difference in voltage or
capacity between his "supernator" which supposedly had an extra 40a
of capacity and a higher voltage regulator, and my stock 110a
alternator.  He kept repeating what was on his webpage, and I gave up
trying to get an answer to my questions from him.

   It's a royal waste of money by the time you get through with
shipping(compared to the local auto parts store; figure at least $60
on top of his prices, for the shipping!), and listers here have
expressed concerns about the quality of his rebuilds which I now
second.  Among other things, my alternator didn't look -anything-
like the genuine Bosch he got back from me; I don't think it was a
Bosch at all(there are certainly no markings to identify it as such.)
The guy is a long time lister so I've cut him a ton of slack on all

Check the diameter of the pulley on the alternator.  There was a TSB
a while back that states a smaller diameter pulley should be used;
the more common larger pulley doesn't spin the alternator fast enough
at idle.  I can't for the life of me find the correct PNs; it's
probably in the family album, which I don't have; maybe someone can
look it up. I can measure the diameter of the pulley on my
alternator, since I know it's the correct one...I'll try to get to it
later today.

could also be:

-corrosion on the battery terminals(easy check)
-battery on the way out(have it tested if convenient)
-infamous "cable splice" problem(symptom is a large voltage
differential between alt and battery and battery doesn't charge well;
search the archives to research this one, it is very difficult to
repair and so you should be absolutely positive it's the problem
before you try to fix it)

My bet is that you're seeing the low voltage light at idle, and it
goes away with a throttle blip.  If so, the pulley is too large.
Anyone who sees sagging voltage at idle that goes away with a slight
raise in engine speed off idle has the same problem.

"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin

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