w211 no start intermittant crank problem
 

2005 e320 cdi-battery was flat so i jumped it with a jump pack. cranked ok but didn't start. next day tried again but now it wouldn't crank. replaced the battery with a new interstate and still wouldn't start, won't crank most of the time but does try to crank occasionally. doesn't seem like the starter but I'm not sure. any suggestions?
Thanks
G

If engine is turning over I'd be surprised if starter issue. I'd start by confirming you have fuel getting to the fuel rail to start. Any codes?

yeah some ongoing codes that predate this issue....i was thinking dead short but then it started doing this cranking once in a while.