# FUUCKKK, friend tried to install subs in bmw, now wont go into drive!!!

**URL:** <https://forums.speedlife.net/t/fuuckkk-friend-tried-to-install-subs-in-bmw-now-wont-go-into-drive/260954>\
**Category:** Shift518 Automotive\
**Created:** [October 21, 2011, 2:08am UTC](https://forums.speedlife.net/t/fuuckkk-friend-tried-to-install-subs-in-bmw-now-wont-go-into-drive/260954 "2011-10-21T02:08:40Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![Cossey](https://avatars.discourse-cdn.com/v4/letter/c/3ec8ea/32.png) [@Cossey](https://forums.speedlife.net/u/Cossey)\
**Post date:** [October 21, 2011, 6:58am UTC](https://forums.speedlife.net/t/fuuckkk-friend-tried-to-install-subs-in-bmw-now-wont-go-into-drive/260954/11 "2011-10-21T06:58:29Z")

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> [@Shredd And Reagan Cruise Nights](https://forums.speedlife.net/t/shredd-and-reagan-cruise-nights/46067/35):
>
> Old battery is less then a yr old, just left the doors open and radio on without the car on too long when trying to do the install… Car starts right up everytime after I drove it to work this morning. Didnt know that about having to calibrate the alternator… good to know.

Ah, I didn’t know if it needed replacing or not.  
All BMWs made after like, 2002 need to have the alternator calibrated when a new battery is installed. It’s because the alternator “learns” from the battery how good or bad it is, so the alternator will work itself harder to keep the battery optimum. If you don’t calibrate w/ a new battery, it’ll continue working harder and fuck your new battery up. I miss the days of buying a $60 battery from AAP and being good.

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