Basic setting of control pressure regulator on CIS-E3

[Huw Powell]

> I have an '89 100Q with engine code NF. The previous owner had messed with
> the basic setting of the CPR (the 2 mm allen on the back of the CPR),
> probably the mixture screw between the metering head and the air boot too,
> and the car had a major vacuum leak in one of the ISV hoses. I replaced the
> ripped hose, but something is not right. 
> I have a car that runs great when driving, but if I press the clutch, it
> will drop to about 500 rpm, back up to 1300, down to 600, back to 1100 and
> then between 600 and 800. It will never settle completely.

Yup, the mixture is off.

I have no idea what "basic setting of the CPR (the 2 mm allen on the 
back of the CPR)", since the CPR is not adjustable.  Odds are the static 
mixture was just enriched at the metering head.

So, if you have a meter that will read mA, you can set it up and dial it 
in at warm idle so the CPR current oscillates around 0 mA (instructions 
and pictures hidden somewhere on my web site)

If you don't, you can experiment by leaning it out a bit.

1. start with car warm and idling.
2. using 3mm hex key, first make sure it is making good "contact" in the 
adjuster.
3. lean is counterclockwise - try turning it about 1/4 or so of a turn 
at a time, then taking short test drives or just test revving at rest. 
Keep track of how much you turn it in case you want to make it "as it was"!
4.  at some point that idle hunt will start to settle down, maybe you'll 
even get rid of it.
5. if you really have no vac. leaks left, once you get it right it 
should run well at start, cold, warm, acceleration, etc.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/