Quote:
Originally Posted by ard
Battery.
The 'smart' battery management system is conserving battery current for the starter, but at the cost of starving other components (hence the misfires and stumbling).
It can surely be surprising, since in the good old days, there was one +12V wire, and if there was power to crnk there was power to start- but no so much these days.
Thats my vote!
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Forgot about that depending on where you live. These BMW's are heavily dependent on stable voltage of just over 12v. On my 11' 550i i had to deregister my battery to get rid of a lot of gremlins. I don't drive it that often and it has that stupid "efficiency dynamics" which only charges when you decelerate, so no short trips!
I'm having an issue similar to yours with my 4.8. I know its vanos related though as i just changed all 4 vans solenoids and got back my power, but on cold days its like the bank 2 intake vans is sticking or not getting enough oil pressure to move the cam and advance the timing so i get the code p0021.
when it starts it takes a bit longer and then 5 seconds later you hear the engine rev up to 1500 for a second and then come down. if i don't tap the throttle it may throw the code. if i turn it off an on again its all good. Driving me nuts!
Good luck with yours!
BTW, multiple missfires on these n62's and even m52's can be vanos related sometimes also, but you really need to scan after the battery is changed.