[JoanLluch]

Hi all,

After some minutes of driving my M2 Competition, fuel consumption when coasting with any gear engaged gets stuck to a certain value, and there's almost no engine braking, with NO THROTTLE applied to the pedal. I uploaded a couple of videos showing this, see links

https://youtu.be/izvR8eHq4b0

https://youtu.be/LDXK1SDH_Eg

This only happens after some time driving the car (maybe 2 minutes or so after starting the engine) and it resets to normal (zero fuel consumption with no throttle, and normal engine braking) after stoping the engine for a while and then restarting it.

I consulted the local BMW dealer and they have looked at the car but they are unable to find anything wrong with it. They even said this is "normal" for this car model. However, I have never seen that behavior in any other car that I have tried.

I expect fuel consumption to go to zero when coasting, for example on a down slope, and get normal engine brake if no throttle is applied and a gear is engaged.

Please note that this is the Euro version so fuel consumption is indicated in "liters per 100 km", not "miles per gallon", so a higher l/100km figure indicates a higher fuel consumption

First video is with 6th gear engaged.
Second video is with 2on gear engaged.

Has anybody observed this behavior on their cars? Any ideas?

EDIT. I made a video showing more evidence on this issue https://youtu.be/huNVblWaXvw

[DanG]

When the engine is on there is always fuel consumption even with no throttle. The car is set up with minimum fuel to idle.

[Fred Conoway]

That is very strange behaviour. When coasting in gear (no throttle whatsoever), the fuel injectors should turn off completely as the rotational momentum from the wheel keeps everything turning (gearbox, driveshafts, engine, etc.). This is why you slow down quicker when your in gear, as the frictional losses from all these components causes the vehicle to slow down. When shifting to neutral, what Dan said above is correct; there will be a minimal amount of fuel used to keep the engine at least idling since it is disconnected from the driven wheels.

I have a manual, and what I stated above is exactly how my car behaves. I can't comment too much on a DCT vehicle, but I would say that what you've shown in your videos is NOT normal

[JoanLluch]

Originally Posted by DanG

When the engine is on there is always fuel consumption even with no throttle. The car is set up with minimum fuel to idle.

This is not correct. Fuel injected engines should switch fuel completely off when coasting except when rpm are very near idle revs. That's what I observed in ALL the cars that I drove before. If you look at the videos you will see that this car is definitely not behaving like that

[JoanLluch]

Originally Posted by Fred Conoway

That is very strange behaviour. When coasting in gear (no throttle whatsoever), the fuel injectors should turn off completely as the rotational momentum from the wheel keeps everything turning (gearbox, driveshafts, engine, etc.). This is why you slow down quicker when your in gear, as the frictional losses from all these components causes the vehicle to slow down. When shifting to neutral, what Dan said above is correct; there will be a minimal amount of fuel used to keep the engine at least idling since it is disconnected from the driven wheels.

I have a manual, and what I stated above is exactly how my car behaves. I can't comment too much on a DCT vehicle, but I would say that what you've shown in your videos is NOT normal

Thank you for your response. I totally second what you said and this car behavior looks NOT-NORMAL to me also. This car is Manual Transmission like yours also, not DCT.

The local BMW dealer said this is normal for this car model. But I just can't believe it. It's just against any experience that I had with cars before

[Fred Conoway]

Originally Posted by JoanLluch

Thank you for your response. I totally second what you said and this car behavior looks NOT-NORMAL to me also. This car is Manual Transmission like yours also, not DCT.

The local BMW dealer said this is normal for this car model. But I just can't believe it. It's just against any experience that I had with cars before

Apologies, I didn't realize it was a manual in your initial post!

I would try taking it to a different dealership if you have one available in your area.

[JoanLluch]

Originally Posted by Fred Conoway

Apologies, I didn't realize it was a manual in your initial post!

I would try taking it to a different dealership if you have one available in your area.

No problem.

I already did, but the outcome is always the same. They would eventually connect the car to their diagnostics system, the system doesn't report any issue, then they refuse to escalate my concern to BMW because without any "objective evidence of malfunction", BMW will simply refuse any query. They also said, just enjoy the car and forget about that minor detail. But of course I want to go to the bottom of it because as said this does not feel normal at all to me. So basically I am stuck and don't really know what to do.

I suppose if I get several confirmations from BMW M2 Comp owners in this forum that this behavior is NOT normal, and it does not happen on their cars, I may have some more power to battle the case with the BMW dealers

[captain slowly]

I'll look and see what mine does, and let you know, but ultimately why do you care? If there are no codes nothing is wrong. There is no way its dumping fuel into the cylinders when it isn't supposed to, check engine light would be on immediately and it would run like shit. If its a fuel economy you are concerned with, you bought the wrong car. I struggle to get 20mpg and frankly, I don't care.

[JoanLluch]

Originally Posted by captain slowly

I'll look and see what mine does, and let you know, but ultimately why do you care? If there are no codes nothing is wrong. There is no way its dumping fuel into the cylinders when it isn't supposed to, check engine light would be on immediately and it would run like shit. If its a fuel economy you are concerned with, you bought the wrong car. I struggle to get 20mpg and frankly, I don't care.

Well, the concern is not fuel economy of course. The car actually feels slightly different when it is in "normal" mode, i.e. during 2 minutes after engine start, than when it's in "not-normal" mode. The difference is that when normal, the car has normal engine braking. When the car switches to "not-normal" it actually feels as if a small amount of throttle is applied all the time, so engine braking is reduced and the use of the actual brakes are more necessary because the car would simply not reduce enough speed by just leaving the throttle, and even a small jerkiness is perceived at low rpm with no throttle. Anyway, thanks for looking into your car behavior

[David1]

There is nothing wrong, just drive it. Fuel economy gauges are nothing but a gimmick. They are programmed to display based on speed and throttle values and not what is actually going on. I don't pay attention to fuel economy gauges especially in the M2C since since it has lousy economy especially when compared to the N55 M2.

[JoanLluch]

Originally Posted by David1

There is nothing wrong, just drive it. Fuel economy gauges are nothing but a gimmick. They are programmed to display based on speed and throttle values and not what is actually going on. I don't pay attention to fuel economy gauges especially in the M2C since since it has lousy economy especially when compared to the N55 M2.

I understand that, but it's not at all about fuel economy, that's just the way I have to show the issue. It's about the car behaviour after it enters into such non-standard mode.

As I said it feels like a small amount of throttle is actually applied to the engine, thus making it less pleasant to drive because the car would not have the normal engine braking response that we all expect when not applying throttle.

I mean it's a real thing, not just a weird indication on the panel.

Also note that the car does not do that all the time. During the first 2 minutes or so after starting the engine, and if I drive it really slow, then the car will not enter into that mode, and it will behave normal with normal engine brake response and so on. (I edited my opening post to make that clearer)

[Daytona_550]

I guess you have not been able to get the BMW service techs to drive the vehicle under both the normal and not normal conditions (so they can witness the difference that you describe)?

If you have (or can buy) an OBD reader, you may be able to:
1. Download a free OBD app for your phone that reads RPM.
2. Run the app “live”, as you drive the car in “normal mode”.
3. Do a “record session” in the app. If the app does not have a record feature, do a screen record through your phone.
4. simulate a coasting scenario while in “normal mode”.
5. Repeat the process while driving in the “not normal mode”.
6. Same vehicle speed and gear when initiating the coasting in both scenarios.

Would this help you document how the car’s RPM are higher in the not normal mode?

[m5_mbb7]

Lots of misinformation in this thread from some apparent forum warriors who don’t know what they’re talking about. To everyone saying to just enjoy the car, that is BS and something like this will make the car more difficult to track. How can you say that, when someone buys a car they expect it to behave consistently both in its operation and in comparison to other cars of the same model. Engine braking makes a significant difference to braking distance as well and I suspect the engine would still be giving it a little throttle even while braking which would increase those distances. On top of that sometimes on track you need to engine brake or coast and you don’t want any throttle. I say go to BMW and insist they check the throttle actuator motor because it may have failed. These are track capable cars and this behavior is contradictory to that; this is most certainly not normal behavior. I have a manual m2c and this would bug me so much.

Try bringing it to another dealer and complain about the increased stopping distances and insist they check to make sure that the engine is not giving throttle while you’re off gas (and braking). A complaint about stopping distances and braking should get them going a bit more because it’s lawsuit (or lemon law) territory

[thebadboy]

engine warm, how many rpm is the engine idling?

[ashmostro]

Have you tried resetting throttle adaptations already?

[JoanLluch]

Originally Posted by Daytona_550

I guess you have not been able to get the BMW service techs to drive the vehicle under both the normal and not normal conditions (so they can witness the difference that you describe)?

If you have (or can buy) an OBD reader, you may be able to:
1. Download a free OBD app for your phone that reads RPM.
2. Run the app “live”, as you drive the car in “normal mode”.
3. Do a “record session” in the app. If the app does not have a record feature, do a screen record through your phone.
4. simulate a coasting scenario while in “normal mode”.
5. Repeat the process while driving in the “not normal mode”.
6. Same vehicle speed and gear when initiating the coasting in both scenarios.

Would this help you document how the car’s RPM are higher in the not normal mode?

Thank you very much for this suggestion. I currently do not have an ODB reader, but for now I made something different that also clearly shows the issue.

I recorded two video clips while driving the car while it is in "normal mode", and "not normal mode". Then edited the video to show both recordings at the same time while adding a timer. I synced the start at 3000 rpm and stoped the timers at 2000 rpm.

This is the video link:
https://youtu.be/huNVblWaXvw

These are two driving passes along the same exact road, place, and direction. The car had 2nd gear engaged and NO THROTTLE applied during the recording. This was in an industrial area with no activity or cars, this Sunday Afternoon (Euro time). So I had plenty of freedom and time to do it right. I chose a straight wide road with a slight constant ascending slope (I didn't do it on a totally flat road because then the car takes forever to stop when "non normal mode")

To me, it is pretty obvious that there's something weird or wrong with this car. In non-normal mode the car not only takes almost twice the time to coast from 3000 to 2000 rpm, but it travels a much longer distance to get there.

At this time, I just want as many as possible confirmations from BMW M2 Comp owners that this is NOT NORMAL, and this does not happen on their cars

Thanks!

[JoanLluch]

Originally Posted by m5_mbb7

Lots of misinformation in this thread from some apparent forum warriors who don’t know what they’re talking about. To everyone saying to just enjoy the car, that is BS and something like this will make the car more difficult to track. How can you say that, when someone buys a car they expect it to behave consistently both in its operation and in comparison to other cars of the same model. Engine braking makes a significant difference to braking distance as well and I suspect the engine would still be giving it a little throttle even while braking which would increase those distances. On top of that sometimes on track you need to engine brake or coast and you don’t want any throttle. I say go to BMW and insist they check the throttle actuator motor because it may have failed. These are track capable cars and this behavior is contradictory to that; this is most certainly not normal behavior. I have a manual m2c and this would bug me so much.

Try bringing it to another dealer and complain about the increased stopping distances and insist they check to make sure that the engine is not giving throttle while you’re off gas (and braking). A complaint about stopping distances and braking should get them going a bit more because it’s lawsuit (or lemon law) territory

Thanks for that suggestion. Please also watch the video on my previous post, where the case can be seen cristal clear. I was sure there was /some/ engine brake differences, but honestly after recording the video I got shocked that it was that much. Thanks again

[captain slowly]

Originally Posted by JoanLluch

Well, the concern is not fuel economy of course. The car actually feels slightly different when it is in "normal" mode, i.e. during 2 minutes after engine start, than when it's in "not-normal" mode. The difference is that when normal, the car has normal engine braking. When the car switches to "not-normal" it actually feels as if a small amount of throttle is applied all the time, so engine braking is reduced and the use of the actual brakes are more necessary because the car would simply not reduce enough speed by just leaving the throttle, and even a small jerkiness is perceived at low rpm with no throttle. Anyway, thanks for looking into your car behavior

Ok, I played with my car and could not get it to behave like yours, so yeah, something is wrong with your car. Don't know what to tell you...

[Maynard]

This sounds a lot like what my non-M 2 series does in 'eco pro' mode. Could it be that there is some Euro specific software that is causing this (perhaps part of the OPM system)?

[ROASTM]

Originally Posted by captain slowly

I'll look and see what mine does, and let you know, but ultimately why do you care? If there are no codes nothing is wrong. There is no way its dumping fuel into the cylinders when it isn't supposed to, check engine light would be on immediately and it would run like shit. If its a fuel economy you are concerned with, you bought the wrong car. I struggle to get 20mpg and frankly, I don't care.

Also couldn't care less about fuel economy, clearly if you're buying this car, you shouldn't care about that... but that being said, I've averaged between 22-24 mpg on my last 2 fill ups, with a couple slightly longer than normal drives in there (~60 highway miles round trip). Pretty crazy how efficient the S55 is even at 80+ cruising on the highway.

[JoanLluch]

Originally Posted by captain slowly

Ok, I played with my car and could not get it to behave like yours, so yeah, something is wrong with your car. Don't know what to tell you...

Thanks for your report

[JoanLluch]

Originally Posted by Maynard

This sounds a lot like what my non-M 2 series does in 'eco pro' mode. Could it be that there is some Euro specific software that is causing this (perhaps part of the OPM system)?

My wife's car (a BMW 218d active touring) has this "eco pro" mode. However it does a very different thing. This mode disengages the transmission so to leave the car coasting with no engine friction whatsoever. During that, the engine actually goes to idle speed regardless of car speed. This makes sense because it actually saves fuel.

Said that, I agree the issue with my car is probably software related, but not a "feature" but rather a "bug", as it makes no sense whatsoever.