FW: Testing an ISV

[Livolsi, Stephane]

this thread has got me thinking about something...

does the ISV respond to different voltages, or what?
I have an old train transformer from a model railroad that has a variable
output from 0-16V.  If I hooked that up to the ISV and varied the voltage,
should the disk move different amounts?
I only ask because I'm at work and can't do it right now.  I will do it
tonight and report results tomorrow.  In the meantime, anyone BTDT already?

Stephane

> ----------
> From: 	Tom Christiansen[SMTP:tomchr at ee.washington.edu]
> Sent: 	March 25, 2003 4:04 PM
> To: 	quattro at audifans.com
> Subject: 	Re: Testing an ISV
>
> Hi,
>
> >   I am wondering if anyone has a little howto on testing the ISV on an
> >87 4kq.  I looked at, cleaned it, and I still think it is a little
> >funky.  I was wondering what and how much voltage to apply were to
> >verify that it is working correctly.  Any ideas?
>
> As someone said, apply 9-12V to the terminals and see if it operates. If
> the thing moves around in there, at least there's a chance that it works.
> I
> recently cleaned my ISV. I made sure it operated when a voltage was
> applied. But then I put it back on the car, and the idle in closed loop
> started oscillating between 1400 and 1600 rpm. I unplugged the ISV which
> caused the idle to be a bit rough, but stable, at 1000-1100. Then I
> changed
> the ISV and the problem went away.
>
> So to make a long story short, I don't thing there's a sure way of telling
> if the ISV is bad or not. But if the problem goes away when you unplug the
> ISV at least there's a relatively high probability that the ISV has gone
> bad.
>
> Someone on the list - John Sherrow - suggested that a problematic ISV will
> allow air to pass from inlet to outlet when the ISV is closed (no power
> applied). But on both my ISV's (the good and the bad) air will pass
> through
> the valve without applied power. I suppose that's why there's a crack open
> on the ISV disc...
>
> For more info read the "Audi 5000 idle problems" thread.
>
> Thanks,
>
>          Tom
>
>