My 1999 ML320 would not start. After thumbing through these forums a bit, I decided to let it cool for 1 hour thinking it may be the crankshaft position sensor. Went back down to try and start it, still would not start (sounded almost like it was severly out of time)
We had no previous problems except for a clicking(rapid clicking) behind the console when you turned on the heater (unfixed). Anyway it seems very odd that it wouldn't start, so I kept cranking until finally, it started and the RPM's stabilized. I drove it one block to my home and turned it off, It smelled as if the engine's fuel was burning very rich. I went around to smell around my tailpipe, and saw and oil drip, I ran my finger along the inside of the tailpipe, and there was enough oil to coat my entire finger. Any ideas as to why oil could/would be getting into my exhaust system?

 

I think what you have seen is oily residue from burned gasoline. By cranking the engine without ignition, you flooded the system with gasoline. Light fraction evaporate very fast, leaving oily residue.
This way, or another the exhaust would be my last worry at this point.
Make sure the engine runs OK and if you still notice oil on the exhaust, than worry.

 

OK, I understand the unburned fuel residue. Back to the problem of it not starting. Its done it twice now, and just today while driving @ about 45 mph the engine just turns off. One of the times it would not start, so i went and got a crank sensor, put it on, and still would not start. So componet has been eliminated as a possiblility. What else would cause it to behave this way?

 

Im having the same problem! I used to be a mechanic and I could not figure it out. Car would start fine and after about 10 min. it would die (doesn't matter if your driving or parked it would just die) and will not start again for about 35 min. then you can drive it all day but if you turn off the ignition then it starts all over. checked spark, fuel pressure and not one code in computer. repalce fuel filter cleaned TB and replaced plugs.(due anyway) and the cam sensor and crank sensor (know problem with the ML's). Ok so now I took to a independant shop that works exclusively on Merc & BMW's and he could find nothing wrong. I am at the end and other than the computer I have no idea. any help out there would be greatly appreciated??