I would check the fuel pump relay, it should say 6000K on it, if not you have the wrong relay and thus improper rev limit.

Jonathan

__________________
Blue Ridge Mercedes
Jonathan Hodgman
http://www.blueridgemb.com/
Enthusiast Service, Restoration & Tuning.
Follow Us on Facebook!
Located in the Atlanta area
Specializing in all pre and post merger AMG's including Hammers and DOHC M117 engines.
Mercedes Repair Atlanta