'94 540i smokes excessively....help!

[4Rings]

Hello. First post. I'm a long time Audi/Mercedes enthusiast, and I'm looking at what could be my first BMW.

I'm looking at a 1994 540i, automatic. A friend of mine owns a car lot and took it in on trade.
He says when you crank it up, it "smokes like a freight train". He said it will billow black smoke for a while until you drive it a bit. He said sometimes it smokes a lot, sometimes it won't smoke at all. He said the car runs and drives excellently, it just smokes a lot....sometimes.
I haven't had the oppertunity to start the car up myself yet. I'm going to have a look at it tomorrow. I'm just trying to get an idea of what I should look/listen for when I'm messing with the car tomorrow.

Does anyone know what could make the car do this? My first thought was the piston rings, but if it only smokes sometimes, how could it be the rings?

I searched around... and found something about some kind of broken tube or something from the intake that makes it smoke??? I lost the thread, so I'm unsure of the complete details.

If anyone could help me out with this, I'd really appreciate it.
TIA!
-4Rings

[SergioK]

Blue smoke - burning oil. (piston rings)
Black smoke - too rich.

[Kaz]

First thing I'd do with a E34 V8 is to see if the engine's been replaced with an alusil one. A nikasil one could very likely have the eaten-away bores that could cause the smoking.