BMW Repair: 318i -- high idle, vacuum leaks, vent tube

Question
My friend bought an 84 bmw 318i which we have been fixing up. The biggest problem is that it idles very high, maybe 1300 or 1500 rpm (the tach doesn't work). I've checked for vacuum leaks with propane and found none. There appears to be evidence of someone doing a lot of tinkering with the fuel injection system, perhaps to try to solve this very problem. The boot that attaches the air cleaner assembly to the throttle is cracked and i took it off today to make sure there were no leaks. It had quite a bit of oil in it. I've also noticed a white smoke from the tailpipe and the car seems to burn a bit of oil as the sparkplugs are black. Do you think maybe the valve seals are no good causing the oil in this boot, and would that raise the idle?
thanks for any help you can provide.
Best regards,
jeff

Answer
The oil in the intake boot is most likely caused by the valve cover vent tube and is somewhat normal.  When the idle is raised it usually insinuates a problem with a sensor or false air. what about the idle adjustment screw?  Can you determine if the car is running rich or lean?  the idle control computer may be to blame.  Other than that I'd haveto look at it with an exaust analyzer and an ignition scope, also check the crankcase vent tube to be sure the valve is OK, the plugs should not be oil covered but I don't think a bad valve/s would cause high idle.
-cheers