1994 c280 starting problem

[dwcasey]

Sometime it does this, sometimes it doesn't. When it doesn't, you turn the key and it starts right off the bat.

When it doesn't start, you turn the key and the engine won't turn over...the started just cranks and cranks...and if you keep at it long enough, it will evetually turn over.

And, if it you get it to start, there is some black smoke (yikes!) and it kinda sputters for a few seconds, then it get's up to normal RPM's and runs fine.

Any ideas?

Thanks.