Ok, who's hiding my ISV? what is an ISV??

[quk@sievers.com (Phil Payne)]

In message <3371DC16.7D0F@ix.netcom.com> siegfried writes:

> What's an ISV?

Idle Stabiliser Valve.
 
It's essentially a computer-controlled gas pedal with a _very_ limited range.

On most cars, it's a brightish steel cylinder with a very slightly bronzed look 
and a fair amount of corrosion.  It has a two-wire electrical connection on 
one end, an axial air connection at the other, and an air port near and at 
right angles to the latter.  It usually sits on the back of the inlet manifold 
and allows the controller to permit some air to get past a closed throttle. The 
controller actually sends a square wave through the ISV, though the diagnostics 
say to set it up for fixed currents.  The controller plays around with the 
current to set the idle to various values depending on what's going on - 800 
rpm at normal warm idle - up a bit if the battery voltage is low or if the air 
conditioning is on, etc.

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club