I thought I'd try this forum (E36/7 hasn't been of much assistance), since it seems this is a "technical" question. I understand that the 1.8/1.9 liter engines (as possibly the whole BMW line) maintains a slight pressure in the crankcase for proper engine management. I just replaced the crankcase vent valve and tested the manifold vacuum and it "only" reads 15 inches. I've had too many other 4-,6-,8-cylinder vehicles to pull close to 20 inches or more. Can 15 inches be right. I took the reading aft of the throttle body at the fuel pressure regulator port ("T"-ed in). Any help would be appreciated!!