What are these two gizmos...
 

Quick question, unfortunately I don't have any pics here so I will try to use my descriptive powers ;) ...

Can anyone explain to me what the two vacuum gizmos are, that are on the passenger rear of an 1988 930. They are little cad plated cubes, with 3 vacuum lines leading to and from them. They are located just under the intercooler.

I have searched for pics on here, with no luck. I do not see pics of them in the bentley manual, or wayne's books either. I suspect they are vauccum valves of some sort. Its not a vaumn solenoid, or cold start valve, or thermo switch.

Do you guys know what I am referring to? I wish I had pics..

Any idea what these gizmos do? Are they necessary? I assume they are there for emmissions purposes...

Found this in the 930 manuals... They are aparently called the "blow-off switching valve" and "control valve."

Necessary?

Yes necessary and important

sounds like the 2 vacuum solenoids.

The left one switches the air pump diverter valves from the exhaust ports to the catalytic converter, and the right one blocks vacuum retard to the distributor for a couple minutes making the ign. timing advance a little to raise the idle a few hundred rpms for a couple minutes after a cold start.

oh, and yes important if keeping all the emissions stuff working.

Thanks guys...I have to look and see how this is all plumbed. The airpump/emmisions stuff doesn't play a role... :)