Thinking about this a bit, it has two hose nipples so maybe you could connect them with a 'Y' connector then apply vacuum with the Mity-Vac and see if it holds ? .

I gave away my spare injection pump so I don't have a spare VCV to experiment on but only 9" indicates a pretty serious leak somewhere .

You could also disconnect the green and yellow vacuum pipes under the hood and see if that helps ~ the yellow's are for the central locking and the green is for the HVAC .

Please keep us posted .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better