Adjusting idle and mixture

[Aleksander Mierzwa <alex@matrix.com.pl>]

Hi List!

I think it is time to check and possibly adjust idle speed and mixture
on my 5KT. There are two things that doesn't seem right to me:
1) It sometimes idles at ~1100rpm when hot
2) The last emissions test revealed high CO level (0.51%), but good HC
level (85ppm). I think that if it was the cat dying, I would get high HC
emissions as well.

I've searched the archives and I understand that I should set the
current at the ISV to about 430mA and the frequency valve duty cycle to
about 40%. I have couple of questions, though:
1) There are three wires at the connector to the ISV. How do I connect
the DMM?
2) I know that adjusting mixture affects idle speed and vice versa. What
should I set first?
3) I should plug the breathers, right? So, what exactly should I
disconnect and plug? Disconnect the breather hose at the intake boot and
plug the boot or should I also disconnect the hoses at the valve cover
and crankcase and plug respective connectors too? What about the
charcoal canister?
4) The connector for checking the frequency valve duty cycle is the
brown one that hangs near the wastegate, right?
5) I suspect that the idle stabilization system thermoswitch may be the
cause of high idle. The idle speed drops to correct 800rpm if I
disconnect this sensor. Has anyone the specs for this sensor? Wiring
diagram in Haynes shows it is an on/off switch, but it looks like a
variable resistance sensor to me.

I'll be happy if some good soul answers these questions. Foreign books
have exorbitant prices here so I can hardly afford Probst.

Aleksander Mierzwa
Warsaw, Poland
mailto:alex@matrix.com.pl
87 Audi 5000CS turbo (mine)
88 Renault Medallion wagon (mom's)
91 mountain bike (just in case both cars broke at the same time :-)