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Re: voltage variance, '89 100Q

Frank Martin wrote:
> Hi folks. Holiday greetings!
> Anyone have some thoughts on the following?:  For a while now, I've noticed
> that when my car ('89 100Q) is idling, the voltmeter reading "pulses." It
> reads a good +/-14V, but the needle pulses, in time with the engine, to the
> tune of about 1/4 V to either side of the mark.  One can also see the interior
> and exterior lights pulse in intensity, as well as hear it in the fuel pump's
> hum.
> As long as it only did this during idle, I just made a mental note of it, but
> now it's doing this at all rpm's, at a higher frequency of course. At times
> the needle takes to more wild swings. In any case, it looks like "warning sign
> number two."  And I had just been musing that the Audi had been pretty
> trouble-free lately (probably where the trouble began).
> My guess is a problem with the voltage regulator and/or brushes.  I haven't
> changed one of these, but it looks relatively uncomplicated. NOTE: I had a
> rebuilt alternator installed about a year/20K miles ago, so I'm surprised at
> any problems in that area. (The battery is only 1.5 years old, and seems to
> turn the motor ok.)
> Any thoughts/suggestions?  If it is the regulator, a good source?
> TIA,
> Frank M.
> '89 100Q
> '88 Mazda 323 GTX

Voltage regulator and/or belt quality und thightness.
Also check alternator for snug/firm mount.
Good luck