Hi that was me with the cold start on a IDI N52. Still working on that, but a serious issue was the P-side engine ground strap had snapped and the D-side was blue and fraying. Bad electricity is bad for everything. I'm still mid-fixing things so don't want to speculate here but bad electricity is bad for everything. Passanger side strap is very visible from above with hood open give it a quick look just to "check that box". Cross-linking my thread for helpfulness:
http://www.e90post.com/forums/showthread.php?p=20998884