View Single Post
      10-08-2012, 10:00 PM   #78
Second Lieutenant

Drives: '15 m235i Vert, '12 328i Sport
Join Date: Jun 2012
Location: Dallas, TX

iTrader: (0)

Originally Posted by Frogman View Post
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.
I've noticed this as well. But I've about convinced myself that it's more a perception than reality thing. When the car starts because I've taken my foot off the brake, I expect it. There's a shake, but it's combined with other motion.

When it starts because it wants to run the A/C compressor, I don't. I know it will do it, but don't exactly know when. And the car (and driver) is otherwise still at the time, so the shake is more noticeable.

OTOH, my biggest complaints is that it shuts off too quickly at a stop. It makes sense to stop at a light, but it doesn't make sense to shut off for a stop sign when all I'm doing is stopping and going. This can't help but encourage rolling stops at stop signs. If it would wait 3-5 seconds before shutting off, that wouldn't be a problem.

I also wish they could do something about the accessory voltage drop when it restarts. My V1 reboots about half the time. I suspect that is at least partially behind the frequent iPod Classic lockups we keep seeing.

Last edited by bacampbe; 10-08-2012 at 10:01 PM. Reason: fixed typos