Thanks for all the responses guys.
Looks like it's the section that's indicated in this diagram. The front vacuum hose is modified to feed the bypass valve and I guess I didn't get the hose clamps tight enough or something. I'll probably order the valve as well just in case that's the problem. Of course this is directly under the manifold so it'll have to come back off.
http://www.estore-central.com/bmw-pa...reather-Valve/