81SC CIS part identification
 

Need confirmation on parts here.

The bottom valve is the deceleration valve, or the AAV? I'm trying to troubleshoot an intermittent high idle (2100rpm), I've read a few threads and was experimenting with pulling the vacuum line but couldn't work out if I had the right one.

http://i1283.photobucket.com/albums/...pszjxqyvab.jpg

The lower pod has a vacuum connection on the outside. Many times I find the line disconnected and plugged.
Bruce

Yes, it has a vacuum line. Is it the deceleration valve?

Aav
 

That is the auxiliary air valve. Check out this web site. Has a great description of everything. 911 CIS Primer - Index

The one with the vacuum line is the decel valve.

Here is another view of an engine similar to yours

http://forums.pelicanparts.com/uploa...1355294367.jpg

You can see the AAV and decel valves look nearly alike, but the decel valve has the vacuum port on the front. In your photo, you can see the port at the very right side of the valve, identifying it the decel valve. The two valves in the picture are in reverse location to yours--your upper valve is the AAV and the lower is the decel.

Ah, thanks for this. The descriptions I have seen/read match your picture, with the decel valve on top, but mine has the decel valve on the bottom.

I wonder why mine would be around the wrong way then? I suppose someone might have a reassembled them incorrectly. If that is the case, then I wonder if that is causing an issue?

Here is a picture of a set up like yours, from a 1981 SC

http://forums.pelicanparts.com/uploa...1334266405.jpg

and a picture of how the devices are connected

http://forums.pelicanparts.com/uploa...1251500884.jpg

You'll notice both devices connect to the metal tubing, and both connect to a molded rubber fitting. In short, it wouldn't matter if the devices were switched as both are connected to the same vacuum system.

Gotcha, thanks. I notice that last picture looks like it has had the 'crush' treatment for the decel valve.

Not sure if I am going to try plugging the vacuum or try the crush treatment.

Also check the that the advance is not sticking in the distributor.

Any advice on how to do that?

Bump in the off chance that someone can answer this Q

Your's is not on the wrong way, The decel is on the bottom. Without a doubt. Word to Your Mother, as Vanilla Ice says.

Lemmie get a pic.

Chill on this for now. You gots you some vacuum advance and mechanical advance. Both can be tested. You have a timing light?

Actually I don't think I do. I did have once, long ago when the earth was green and children respected their parents. This is the way to test, with a timing light? Maybe I can find one somewhere.

Ossiblue's second pic is correct.

http://forums.pelicanparts.com/uploa...1439865009.jpg

So I golf tee'd the vacuum line and the driveability of the car at low speed is transformed. It's like it had three flywheels in it before.