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      03-22-2013, 07:31 AM   #151
CSBM5's Avatar

Drives: 2011 M3, 2001 M5, etc
Join Date: Nov 2005
Location: Raleigh, NC

iTrader: (1)

Originally Posted by andret View Post
The clunk when slowing down in 2nd off throttle at 1200rpm. Apparently it is the injectors kicking in before the revs get too low. I think this ma also be related to efficient dynamics regen braking. I wish this could all be programmed out. Could this limit be lowered to 600rpm?
Nothing to do with efficient dynamics. This is standard operating procedure and dates back to the introduction of Bosch Motronic in the early 1980s. On a closed throttle, there is zero fuel flow until the rpms fall enough (generally between 1500 and 1200 rpms, depending on the engine) that it must resume fuel flow or else the engine will potentially stall, i.e. not be able to resume running if fuel flow was enabled at a lower rpm.
Current Stable:
2011.5 M3 sedan 6MT, Silverstone, slicktop
2001 M5 LeMans Blue/Silverstone
2006 330i 6MT Red/black, ZSP, Nav, etc
2007 328i wagon Silver/gray