Originally Posted by jt8307
Thanks for posting about this issue. I have been meaning to post about it for a while but have been too busy with work to get on the forums. I have had my 2018 M240i for 7 months now and have about 9k miles on it today. I took the car in for an oil change in mid May around 5k rpms (have taken a few long trips since). Prior to this service, I never had any issues with up-shifts, and the car behaved like the many manuals I have had when shifting under load.
While in for service in May, the dealership updated the car with the latest software. On the drive home I noticed that the rev-matching was changed for downshifts and it finally worked as one would think it should have from day 1. Prior to this update, the car would not rev-match if you went down more than 1 gear at a time. Now the car will rev-match every time. Example, before if I was at cruising at low rpms in 5th gear and down shifted directly from 5-3 it would not rev match. Also, if you depressed the clutch and went 5-4-3 while the clutch was engaged, it would rev match from 5-4 but not 4-3. Post update, it rev matches in every situation, on every gear change. This was the good part about the software update.
Now the bad. A few days after this update (as i don't drive like a hoonigan all the time), on up-shifts under higher load, the car would surge in rpms as you described. On shifts above ~5k rpm under load, the following events would happen:
1) Let off the gas to start the gear change 2) Engage the clutch 3)RPM's would momentarily drop 100ish RPM as the engine starts decelerating, then jump up 500ish RPM while changing gears 4) Disengage the clutch 5) Back on the gas
This was extremely repeatable, and not an issue prior to the update. It is also more severe in sport than comfort mode. Another side effect of this issue is that it made it more difficult to get the car into the next gear on up-shifts. I contacted the dealer, took the shop foreman on a ride, and he confirmed that it is not normal or intended behavior. They took a data log from my car, a video, and sent it off to BMW.
Fast forward to the end of June, the foreman called me back and told me they got a new software package and installed it on a car they had on their lot and it fixed the issue. I took my car in, got the new software, and it is much better in comfort and sport mode. It is still not 100% as I would expect, as the car still seems to hang a bit during up-shifts under load, but in no longer jumped to a higher rpm. That said, there is one time it did still do it, but this was in Sport+, which I do not go in often, so it appears it is not completely solved.
To me it appears to be related to the wastegate timing, almost as if the car is not relieving pressure fast enough during the gear change. It isn't driver error and related to a clutch/throttle timing issue because if you engaged the clutch before letting off the throttle fully, the rpm's would not momentarily decrease and then increase again. Also, you, myself, and the shop foreman were all able to reproduce it, so it is independent of driver. What also leads me to believe that it is related to boost/wastegate timing is that when you do complete a shift and stay on it when it occurs, the car is viscous when you get back on it, similar to a powershift where it maintains full boost during the shift. While this is fun and exhilarating, I can't imagine it is good for longevity of the powertrain.
So bottom line is you are not alone, it is a repeatable event, and it is not intended behavior. Now that I see I am not the only person with this issue, I will also go back to the dealer after I test it out a few more times to see if the issue is still there in Sport+ mode only now, and then follow back up with the dealer.
My suggestion is to take your car in, explain the issue, and ask for the latest software update. The worst part is that this is an issue that did not exist, was created, and now they can't seem to fix it 100%, at least not yet. It just baffles/frustrates me as this was not a problem when I originally got the car, but now it is. One would think that they would just compare the software versions, isolate the changes, and then correct the problem. For those that do not have this issue, I would suspect it may be that you are on a different software version. Prior to this, I still had the original software from when I took delivery last October. Also, I do have a video of this, I just need to figure out how to post it online to this forum.
~ J
|