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      10-02-2012, 01:29 PM   #74
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Drives: 2012 F30 328i
Join Date: Mar 2012
Location: SoCal

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Originally Posted by 328inGE View Post
So is this vibration/shudder people complain about different than when you start up the car? For me, its the during start up and auto stop/start operation. Are people expecting the car to start back silently or is there more to this?
For me, an auto-start with the A/C off is quiet smooth; usually smoother than a manual start up.

I get really rough auto-restarts when the car decides to restart itself due to A/C demand. It feels like the A/C compressor is engaged during the restart putting extra load on the starter/engine. The whole car feels like it's shaking. Passengers can feel it too and say "what the hell was that!". That shaking can't be good for the motor mounts.

I've noticed that when manually starting the car, the A/C waits a bit before engaging.

Does anyone know: When A/C demand restarts the engine, is the compressor engaged? I wonder if it's not just a stupid logic issue where the A/C compressor should be off during the restart and not kick in until the engine stabilizes.