Re: Fun with the V6 ISV (or "Honey, you said this would only take 30min")

[Todd Young <tyoung@wamnet.com>]

Chris Newbold wrote:

> Over the weekend, I decided to clean the ISV on my 1993 90. I've been having
> some problems with bucking transitioning on and off the throttle and, when
> cold, the engine stumbles immediately after firing. So, with a bit over 70k
> on the clock I thought it would be worth it to make sure the ISV wasn't
> sticking...
>
> The ISV appears to be readily accessible on the 12v V6: remove the plastic
> cover around the intake manifold, and there it is, mounted vertically to the
> left-rear corner (while standing in front) of the manifold, right next to
> the throttle body. In reality, it's a little more complicated, as are all
> things Audi.
>
> It's mounted to a plate on the manifold by three studs, about 3" long. So,
> you need considerable clearance to slide it off. Here's the procedure which
> I developed empirically:

<snip #1-7>

> Reassembly is roughly the reverse...
>
> The ISV appears to be different than those I've seen described here before.
> This one is manufactured by VDO, and has two adjacent ports on the mounting
> face on the side. The control mechanism is in a vertical, cylindrical casing
> at the top. Air flows in through one port, turns 90deg. and goes through a
> U shaped passage, turning 90deg. again on the way out the other port. Sort
> of like the trap you find in a sink drain.
>

My car: '93 90S

I've had mine off too, but I did a lot less work. For removing the nuts that hold
the ISV on, I think I used a {deepwell socket-ujoint-extension-3/8"drive rachet}
combination. I pulled the hoses and electrical connector off of the ISV and tried
to wiggle it out, no luck. Under the ISV is an electrical connector that I didn't
bother to analyze, I just disconnected it [and managed to break off one of the
two lock tabs] and then managed to wiggle the ISV out of it's nice tightly
confined space. Of course, installation was the opposite. Make sure you reconnect
the electrical connector underneath the ISV; it's not for the ISV, "Team Door
Handle" just decided to put it there to make life difficult.

After removing an alternator and a water pump from a 1986 Mazda 323 engine
compartment, I've become quite the expert at "wiggling" components out of tight
spots.

--
Todd Young              WAM!NET Inc.
tyoung@wamnet.com       6100 West 110th Street
612-886-5051            Bloomington, MN 55438-2664
800-585-1133 ext.5051   http://www.wamnet.com/