Still love BMWs but if they won't fix this F10 under warranty what hope is there in the future? Probably more a problem with this particular dealership that is owned by BMW of North America.Have they put you off the marque completely or just the prospect of keeping this car?
Never got the warm & fuzzies from Manhattan, but that was my experience...I'm sure that people think they are the best...Still love BMWs but if they won't fix this F10 under warranty what hope is there in the future? Probably more a problem with this particular dealership that is owned by BMW of North America.
I'm convinced BMW deliberately modified the DCT software to lessen the possibility of damage. Didn't they do something like this to the E60's SMG?Crikey.
While it's nice to see that the technician can at least spell and string together a sentence... the level of denial is fantastic. I thought "They all do that, sir" had gone by the wayside. Clearly I was mistaken.
In answer to your first question, no. The following is a detailed description of what is happening and confirmed by Rheingold BMW diagnostic software during 3 hours of road testing. I should reiterate that this is a new phenomena which started occurring last April.When the clutches 'release' as you say they do, can you freely rev the engine yourself, as if you'd depressed the clutch pedal on a manual car and hit the gas pedal? You say the revs stay high, but I'm still not 100% sure I get the issue. There is precious little engine braking with these cars anyway so I'd like to understand the actual fault you experience a little better.
--RayWhen manually downshifting at highway speeds (>60 mph) the F10 rev matches and engine braking begins and then inexplicably the clutches disengage. The net result is that the F10 coasts and the revs stay elevated. Application of throttle is required to re-engage clutches. This phenomena will also occur occasionally while cruising at higher rpms. BMW of Manhattan has finally conceded that the F10 hasn't been fixed and will enter the problem in PUMA.
After manually down shifting rev matching occurs and initial engine braking begins. After about 1 second engine braking ceases and revs stay elevated. F10 is coasting with clutches disengaged and Valvetronic keeps racing at rev match rpms. Watched the clutch operation do this while using Rheingold BMW diagnostic software.So you change down, the revs rise to match the new gearbox speed, and the revs stay high. Surely they would do, unless you actually change the speed of the car? I don't doubt you have an issue here, I'm just being a bit slow at grasping it - apologies.
Rheingold allows you to monitor what the DCT clutches are doing. I was driving and George Boutsikos was monitoring Rheingold on his lap top. His observation was that both clutches were disengaging during our testing. It would be the equivalent of what happens when stopped at a traffic light or putting the DCT in neutral.There's a few things I can't get my head around, and was hoping you could elaborate on: How do you know the clutches have dis-engaged or re-engaged? Isn't the point of a DCT that one of them is always engaged? Does the software you used to analyse this tell you which of the two clutches is being used to transmit power at any moment? And therefore, is it always the same one 'failing'? Also, which gears does this happen in? Again, apologies if I have completely misunderstood the concept of a DCT gearbox. Perhaps someone could enlighten us?
When I first leased my F10 the DCT functioned perfectly in all modes including manual downshifts and engine braking. BMW won't admit it but I'm certain this new behavior is the result of their tinkering with the software. It's no longer fun to drive; might as well get a 7 Series. In addition to the engine braking issue, the F10 frequently maintains highway speeds for protracted periods after taking your foot off the accelerator pedal (think cruise control engagement) which is an even more dangerous situation. This is why it's going back to BMW when the lease ends in October. George Boutsikos at M-Chanics can give you more detail on the tests we conducted.I'd like to understand how these 'wet' clutches work to really understand what's going on here. I read a bit and I'd never realised just how like an automatic gearbox a DCT is. You never get much engine braking with a traditional auto. Combine that with low compression and you're going to struggle to get much at all - as I find on a daily basis. When the software says the clutches are disengaged, exactly what do they mean? It's not as black and white as a dry clutch...... Can the Rheingold guy offer any insight?
Any (fuel injected) engine will use zero fuel when coasting on a closed throttle, (ie. lifting off whilst in gear in a manual car) and 'some' fuel when coasting on an idling throttle (ie. clutch pushed in on a manual car). The car is also under less control and so is less safe. On top of that, you refer to your revs staying high, which would surely always use more fuel than either scenario I mentioned above. I can't believe BMW would introduce such a feature, but then I have been wrong before....??Beginning in 2014 BMW installed a "sail/cruise" feature on vehicles with automatic transmissions to improve fuel economy. It is part of Eco-Pro mode. When cruising at speeds of 30 mph to 100 mph in this mode, taking your foot off the accelerator disengages the transmission from the engine and the vehicle coasts. This is a known phenomenon on Boards other than the M5.
Found out about this serendipitously while reading an article about the 2016 7 Series where they were extolling the sail/cruise feature. Supposedly this feature can be turned off through the I drive controller. I will explore this on the coming weekend when we'll be going on a drive.
This alleged feature should not be on an M5 IMHO.