While re-instaling my air control valve in my 1990 740 non-turbo, my arm somehow pulled out a vacuum line from the drivers side of the engine compartment, and I don't have a clue where it went.
It is a yellowish plastic line approx 1/8" OD, that comes out of a right angle stub in the intake manifold, it is about 3 feet long. Any ideas?
Thanks in advance for your help.

 

I believe it is the vac. line for the EGR valve. Is there a vac diagram on the hood? It might help.

B

 

i agree with EGR line. EGR vacuum booster to manifold line or EGR vacuum booster to EGR valve.

 

I finally tracked it down, and it was a line to the manifold pressure switch, which is located under the little support strut next to the drivers side hood mount.
Thanks for the help.