Thread: 530d idle
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      08-29-2015, 09:42 AM   #2
HighlandPete
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Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

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Quote:
Originally Posted by e92liv View Post
Curious if I'm the only person getting this but when when in D and foot on brake the car vibrates slighty (if autoH is on and I remove foot from brake then rattle goes away)

But if I move the stick into sports mode with foot on the brake I don't get the idle rattle

Anyone else find this?
This is only a guess, but wouldn't be surprised if it is not associated with NIC (Neutral Idle Control). Involves the disengagement of the torque converter, when stationary and at idle, using the foot brake. I imagine the strategy is different in sport mode. The reason for saying that, in older models using the ZF 6-speed box, the 'jolt' issue (involving NIC) was only reproduced in normal mode, indicating sport mode is set up different for NIC function. I assume it may not disengage in sport mode allowing a more rapid (time wise) take off from standstill.

Engine and gearbox are in a different state when NIC is active, less load on the engine, the likely cause of different vibration/harmonics.

HighlandPete
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