cold start valve- part II

[Huw Powell]

> no, i mean the cold start valve!

Uh oh.  It shouldn't affect idle once the car is running, and it
shouldn't buzz either really.  It should only be activated for a few
seconds right at a cold start (Bentley should have graphs showing
duration vs. temperature).

I wonder if the switched ground wire is chafed somewhere?

> 
> > thanx for all replies.  haven't been able to remove the valve for
> > testing but i did check for power to the electrical plug and it was
> > fine.  i did notice that when i unplugged it it stopped buzzing and
> > when i plugged it back it started buzzing again. It also appeared that
> > it had an affect on idle when i unplugged it.
> 
> Well, for starters you are talking about the Idle Stabiliser Valve not
> the Cold Start Valve (which is an extra injector in the intake manifold)
> 
> the ecu regulates the idle by controlling how much air gets around the
> throttle body, thru the ISV.  That why it buzzes.  When the engine is
> cold it lets a lot more air in to maintain the idle.
> 

-- 
Huw Powell

http://www.humanspeakers.com/audi/

http://www.humanthoughts.org/