Re: idle stab system

["Avi Meron" <avi@cosmoslink.net>]

Most of the time the failure in the idle circuit (if it is ISV related ) is
in the mechanical of the ISV valve. One way to verify this, is also to plug
the 2 ISV openings and see if the idle stabilize some (works only on manual
transmission), if it does, you might have an ISV problem (valve, not
circuit). another issue which will give you high idle (other than air leaks)
is incorrect CO mixture, but you must ELIMINATE all air leaks BEFORE
adjusting the mixture.
Avi
-----Original Message-----
From: Vytautas Reipa <vytas@pop.erols.com>
To: quattro@coimbra.ans.net <quattro@coimbra.ans.net>
Date: Sunday, January 25, 1998 9:49 AM
Subject: idle stab system


>Hi Everyone,
>
>Here I am again, confused and seeking info from you, the experienced. Still
>cannot figure out the cause of high idle on my 86 5kcst (MC engine). For
>some reason my Bentley does not give the checking procedure for ISV system
>on this car, therefore I used the one described on page 25.7 (WU, KZ
>engines) because the relay wiring description fits mine. Everything was OK
>except the voltage on the valve with ignition on was 3V instead of battery.
>The voltage on my 87 5ks ISV is battery but its different system according
>to the diagram. So what the correct voltage reading should be on MC's ISV
>with the ignition on? Or maybe there is some way to check the ISV relay? My
>sincere thanks for your precious input.
>
>Vytas
>
>86 5kcst (still undrivable)
>87 5ks
>