380SL Part Identification - Damper?

[Dohea]

Hi All, I have an Australian delivered 1982 380SL and am hoping someone can tell me the correct name of the component circled in the below image and explain what it is supposed to do. I'd also like to know if there is a cap missing off the top or whether it is meant to be open like mine is.

I have been having problems with rough idle when coming to rest after high speed driving eg 110km/h for >15 mins. The problem corrects itself after about 10 minutes of driving around at city speeds. Whilst checking the ignition timing I noticed that occasionally the above mentioned component produces a loud hissing (vacuum) noise whilst its popup valve in the centre remains raised and this is accompanied by rough idle. If I cover the opening at the top of the component or push down on the raised valve in the centre the idle smooths out. I'm suspecting that this component may be contributing to the rough idle after high speed running and will check tomorrow if I get the opportunity. I have checked for other vacuum leaks and in recent years replaced the injectors, spark plugs, ignition leads, distributor cap and rotor, fuel accumulator and filter.

Damper_1.jpeg

Damper_2.jpeg

There are three hoses connected to the above component; 8mm to intake manifold, 8mm to base of fuel distributor, 4mm to the device located on the fender and pictured below.

IMG_8461.jpeg

[John Green]

That is part of the emissions system. The cap coming off is reasonably common, usually due to a backfire at some stage. From memory 5cent piece fits the hole perfectly.

Or get rid of all the emissions gear altogether, it serves very little purpose and just creates hassles. Do you still have the air pump connected?

[Dohea]

Thanks John, the belt is no longer on the air pump but all pipes/hoses are connected. I’m not confident in knowing what can be removed/blocked without causing other issues, but I’d like to.

Interestingly I can’t see that part in any of the parts diagrams for my vehicle.

[John Green]

Thanks John, the belt is no longer on the air pump but all pipes/hoses are connected. I’m not confident in knowing what can be removed/blocked without causing other issues, but I’d like to.

Essentially all you need is vacuum advance to the distributor, vacuum to the warm up regulator and the idle up system for when the a/c compressor cuts in. If you do some googling you should be able to find diagrams for the Euro spec engines which were much simpler than the Australian ones.

[Dohea]

Cheers John :-)
Regards
Andrew