I just Purchased Mercedes about two months ago with 104000 miles on it. Car was in need of some attention It did run, took a couple of trys to start and also had fuel knock.
I purchased and installed
new valve guide seals
Injector kit
glow plug update kit and filters
adjusted valves
After purging air out of injector lines car started right up and ran great all weekend with just a little smoke at idle.
My wife drove it to work on monday - wednesday. She left the lights on wednesday so battery was dead the next day I tried jump start it in the morning and only ended up with blown glow plug fuse. let battery charge all day replaced glow plug fuse still no start replaced glow plugs with old ones(still decent) still wont start. Checked fuel in tank, checked valve adjustment, starter seems to crank at same speed as before dead battery. I dont really know why it wont start any help would be great.