Marcelo0131

I have a new to me '08 550 56k miles, with most all the factory options. Been driving it for about 6 months now. i drive mostly city city ,so i notice more that throttle reponse has been lagging or just goes flat with no reponse after driving or accerating and having to let of the gas for what ever reason ( still moving but rpms drop to 900-1100rpm) and needing to get back in the gas, there's nothing there for the first 10-20 degs of the gas pedal for s few seconds. Notice alot going around corners or slowing down after accerating but before i come to a stop then rolling on the gas again it feels flat,( lacking power, feels like it got loaded up ie. rich). seems to only happen at low rpm 900-1400rpm. Residental streets driving making slow speed turns(10-20mph)letting off to go into turn and rolling on gas in apex, feels like the theres no power on the first part of the pedal.Like the pump is picking up air or something.
took it to the dealer as it still inder a cpo warr. Service foremore noticed issue on test drive, but said after having it for the day. There was no Ecu updates and no found issues. so he had no clue.
No check engine or warning lights come up ever?
I sport mode it doesnt happen at all i think, as all rpm downshifts are kept above the 1500rpm range. and throttle reponse is pretty much instant.

turboawd

you know, i thought my car has been acting the same way slightly...like its losing its throttle response down low in the rpms, but ok in sport mode.
i wonder if it has anything to do with the adaptive driving thing bmw has. maybe doing one of those 25second throttle reset would help.

shumaki

I've noticed similar on my '08 550. Seems like I'm doing the reset once a week and it helps. I have the feeling switching between econ to sport mode and then back to econ may have something to do with it. Even more sluggish than before switching over.

shumaki

I've noticed similar on my '08 550. Seems like I'm doing the reset once a week and it helps. I have the feeling switching between econ to sport mode and then back to econ may have something to do with it. Even more sluggish than before switching over.

Marcelo0131

How is the throttle reset performed? I'd hate to have to do this every week. Maybe performance tune of the ecu can solve issue. Going to go to Bullit bmw in Costa Mesa, there going to hook it up the there computer and drive it around and watch what is going on. Hopefully we can see what going on.
Was hoping is was something i could just replace..

shumaki

https://5series.net/forums/topic/400...moother-shift/

dingolfing

What you are experiencing is the adaptive transmission function which seems to be stuck in an economy mode, and yes performing the pedal reset will improve your situation. Drive-by-wire is not always fun and I almost wish we can go back to direct mechanically-linked throttle cables. The E39 used throttle cables and the E60 was the first to use an electronic throttle connection. Hopefully BMW fixed this with the F10.

You will know a pedal reset is needed if you apply light throttle from a stop and for a second nothing happens. As you apply a little more throttle, the car abruptly moves forward making it impossible to take off smoothly. Some people seem to require frequent resets. In my case, the first reset lasted for several months and I noticed the problem resurfaced this past week. So I had to reset again. I wonder if there is a way to disable the adaptive function and leave it in a performance "map" mode?

dingolfing

The performance tune and diagnosis sounds interesting. Let us know how it goes

dingolfing

Also realize that driving in auto 'D' will only utilize gears 2-6. I think 1st gear may only be engaged when the throttle is floored and the kickdown button is smashed.

Steptronic mode 'M' also defaults to 2nd gear instead of 1st (though you can select 1st).

Sport mode 'S' only uses gears 1-5 and is the only transmission mode that starts off in 1st gear automatically.

The 550i first gear is very short to allow the engine to reach it's powerband in the mid-range very quickly. Our engines don't have much grunt down low. So you can see why taking a low-speed turn in Sport mode will be more enjoyable and feel more lively than doing same with the tranny in auto.

sahiljain22

Similar symptoms and stealer found a leaking vacuum hose a few months ago. In my case, one day when I tried to do a 0-60, I got a engine malfunction error which forced me to really check what was going on. Restarted that time and error gone. Same error after 3-4 months once. Finally went to the stealer who said the tech "thought" that it could be a hose and he wanted to try changing.

The hose is $30. Trying a 0-100 on a track might not be a bad idea