Audi 200 voltage

[Brett Dikeman]

On Thu, Jul 30, 2009 at 10:32 AM, Geraint Lloyd<geraintlloyd_qc at yahoo.ca> wrote:

> Having played extensively with the injection system and replaced or repaired
> the following items that were either dead or marginal:

New injectors?  I seem to recall Huw saying that CIS injectors aren't
very pricey and the difference in spray pattern can be
substantial....techron et al just won't get everything.  If they have
a lot of miles on them and the price is reasonable to you, go for it
(not necessarily to fix your starting problem though.)

> So it runs pretty well now although there may well be some fuel quality
> issues going on.

How so?  Do you not drive the car often?  If so, keep the tank full
(especially if you live in an area where Cornohol, cough, ethanol is
in use) and add Sta-Bil. Ethanol is hygroscopic, loves to absorb
water.

How does it idle?  Speed is smooth?  Misfires?

> This is because the battery keeps going dead.

How quickly?  If it's any faster than a week or two, you have an
abnormal drain or the battery is kaput.

> I don't appear to have an out of spec drain, but the battery has been
> flattened a couple of times by junior leaving the rear interior lights on
> overnight.

That will kill a battery pretty quickly, yes, especially if the
voltage went below 10.7v.

> With a freshly charged battery and the AC off, I have 13.6v at the
> alternator post.

How did it start on the freshly charged battery?

>  It's been warm
> and humid in Montréal recently and the car spends most of its time in city
> traffic, so low engine speed and the fan running at force 12.

Which stage?  There's low (AC), normal radiator cycling (2) and then
harrier-jump-jet speed, which is triggered by a thermoswitch which
activates at just below the point where the car will boil over.  I've
heard the latter ONCE on my 200q20v...put significant strain on the
battery and was quite loud, and the 200q20v's have the improved fan
blade design (your car may as well.)

What I'm getting at is that it may be time for a new radiator; the
less efficient the radiator, the more time the fan runs.  Is it
original? How many miles?  Do you use the blue stuff, or the green
stuff?  Lot of bugs and sand/dirt where you drive?  Might be worth
popping the top plastic cover off and eyeballing the AC condenser,
where all that crap gets embedded :)

> Do i have a problem, or is it just that the car needs more highway miles and
> less city?

What size pulley do you have on the alternator?  There are two- and
there was a technote, one of them was too small.  Also, are you sure
you have the beefiest alternator available?  A bunch went into these
cars ranging in amperages.  There is no reason not to get the biggest
you can.

Something that may be worthwhile is putting an ammeter on the battery
and seeing how current flows.  Just be very careful that everything is
secure and won't pop off or short while driving, and have a friend
read it from the front seat.

Don't bother replacing the ground strap unless you measure any
appreciable voltage drop between the negative terminal on the battery
and the body sheet metal nearby.  I found corrosion on the body
attachment point on the 200q20v, but didn't make much of a difference-
few hundredths of a volt I think.  After cleaning it up, it did
drop...

HTH,
Brett