Engine idle rpm rises when I let the clutch out. Anti-Stall System?!?

[shanecconn]

Hi All,

I've owned my 2010 E90 320D ED (Efficient Dynamic Model) for about a year now and I have always found it odd that when I have the clutch fully depressed in first gear and slowly let the clutch out (not touching the accelerator pedal), that the engine rpm will rise from around 800rpm (normal idle) to about 900rpm. Then once the car gets moving and I release the clutch completely (still not touching the accelerator pedal), the revs will drop back to normal idle (~800rpm) and the car will roll along without any problems.

While this is far from life threatening, I've always found it odd and wondered if it was some sort of anti-stall system or something else altogether or just plain something wrong with the car. This also did take a bit of getting used to at first as the car will actually accelerate slightly faster than expected while this is happening.

This is my fifth manual transmission car (including an E36 318IS) and I've never noticed anything like this on any of them before (or any car I've ever driven for that matter).

Anyway, any ideas or comments are welcome as I've trawled the net and cannot find any info on this.

Thanks,
Shane.

[RocketSurgeon]

I'm pretty sure the e46 had something similar. I helped a friend disable the clutch switch on his e46 323i and it changed the shifting behavior noticeably.

[shanecconn]

I'm pretty sure the e46 had something similar. I helped a friend disable the clutch switch on his e46 323i and it changed the shifting behavior noticeably.

Hmm, that sounds like a really good idea. Thanks for the tip.

I'd imagine I should be able to find an E90 guide on here for clutch switch repair/replacement or something close enough.

Thanks Again.