nealjr said:
Do N52 Owners need to worry about this?
No, the valvetronic system manages the idling.
Warning! Trivial factoids follow. Some engines achieve idle control by having a little gadget move the main throttle linkage a bit so the throttle valve remains cracked open, allowing idle. The M54 idle valve is a completely separate air intake system. The main throttle can be completely shut and the idle valve provides enough air for the engine to idle. One benefit is the throttle valve can return to a solid home position without risk of stalling the engine, which allows the electronic throttle control to positively know where the throttle valve position is, independent of sensor data.
The separate intake system takes idle air to just outside one of the intake valves. The benefit of this arrangement is the idle air can be used to induce a swirl into the main intake air under certain load conditions to ensure complete and rapid combustion. Additional complexity? Yes. Cool engineering? Absolutely!