Big Dave

I've seen several discussions on checking and servicing the idle stabilizer valve to remedy "lumpy" or "hunting" idle problems.

While I've got my engine apart I figure it's time to at least make sure mine is working properly since my idle was fluctuating up and down. What's the best (and safest) way to check the ISV for proper operation? What's the best way to clean it while it's out?

hacker-pschorr

In the scope of this project, how much is a new one? Not much - just replace it

Big Dave

But that doesn't answer the question. What if it's not faulty?

H2

I replaced mine...only to find that I had overlooked a vacuum leak.

Harvey

Jim bailey - 928 International

New is less than $140

Big Dave

...which is a mistake I don't want to make (i.e., replacing parts that don't need replacing).

hacker-pschorr

Then you have a spare!

No wonder my parts box in the garage needs it's own stall.
You have owned a 928 far too long to make newbie comments like that.

Big Dave

Ahhh....but keeping a well-functioning unit is $0

So...anyone care to answer the original questions?

Big Dave

I already have too many parts taking up space.

hacker-pschorr

Just think - without all of these smart-assed responses, your thread would be at the bottom of the page already!

Audi Coupe's are known for faulty idle/ air valves. We test those with a 9-volt to see if it's opening / closing all the way.

Jim bailey - 928 International

You can look at the brushes on the motor, you can clean lube it with wd-40 / carb spray but there is no real procedure to bench test it.

Shark_gts

If you are lucky and it's a gummed up valve, you can inject a quality lubricant like LPS into the air lines to the idle stabilizer and that will free the unit up to normal function. This has worked great on 2 928's I've had. I've got this 88S4 that needs the throttle part open for starting, and the idle isn't so great. The lube procedure did not work.

SeanR

Ok,

Here is a noob question.

Where is this ISV located?

worf928

To test the ISV: Middle pin is 12v. Hit each of the other pins with ground one at a time. You should see/hear/feel the innards of the ISV move smoothly and quickly.

Big Dave

Circled