Hi

New to forum, and wondered if anybody can help. I've got a 2002 ml270 CDI that is having problems starting, when turning over I can here a popping noise and smoke comes from the engine bay, it has started a couple of times but sounds like a stihl saw very loud and rough. I'm sure I can smell fuel too. I've had a quick look but can't see anything obvious. Any advice or pointers would be much appreciated

Thanks