vacuum unit identification wanted

gordonm

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Mercedes 350sl 1980,Audi A4 3.2 quattro avant.
Can somebody please help identify the component in the picture, the car is a 1980 350 sl 116 engine.
The unit has three hose connections, a small bore hose to the top of the inlet manifold a connection to the fuel distributor and a hose to the right hand rear of the engine, if I disconnect the hose to the fuel distibutor the idle speed drops.The unit has no electrical connections.
The reason I ask is I have renewed the valve stem oil seals and cleaned the inlet manifold, renewed the injector guides and seals and the engine still smokes on startup but quickly clears and I suspect it is unburnt fuel that is smoking on initail run up from cold.
The idle speed is also higher than it was, the cold start valve seems to be operating ok.
Looking through the various posts on vacuum hoses I was unable to identify this part and what it's function is.
Many thanks gordon
 

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gordonm

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I was reluctant to adjust that until I had determined that I hadn't disturbed anything else in my cleaning spree, and I was intruiged that I couldn't find this part in the various diagrams available.
At the moment I have adjusted the idle speed using the idle air adjustment.
 

television

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You only have 2 adjustments on that engine, the C02 adjust, just behind the air flow plate, and the big idle adjust
 
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gordonm

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Found it! its's the ambient coasting air valve apparently now to test it.
thanks
 
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gordonm

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Mercedes 350sl 1980,Audi A4 3.2 quattro avant.
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Yes the valve is faulty which causes air to bypass the throttle and the idle speed to be higher, new valve on order.
But still looking for the cause of smoke on initial run up now I have renewed the valve stem oil seals.
 


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