There was complete 0 information regarding flywheel (Increment wheel) adaptations in the BMW technical materials for a long while. For B series engines, a description of one paragraph has appeared:
I would venture to object – detecting the misfires is not the most critical task of the flywheel balancing! A balanced flywheel is critically essential for DME to correctly even out the performance (mechanical efficiency) of all/each cylinder. When the performance of the engines is evened out, minimal vibration of the engine, both at idle and on the go, is achieved. In addition to this, each cylinder’s correct fuel mixture avoids detonation and damage to the CO catalytic converters; it guarantees minimal possible fuel consumption and the most accurate possible exhaust gas indications.
The menu of deletion of adaptations has become more advanced – it offers the possibility to delete certain (several) groups. Separately you can delete Fuel mixture, Fuel system, VANOS, Valvetronic, or – only the Increment wheel.
I do have some critical objections to this concept:
a. adaptations and their groups are interconnected. In addition, these “connections” are quite ranched, complicated, and – sometimes – even unexpected. For older engines, INPA offered the deletion of separate adaptation groups. Unfortunately, usually deleting particular adaptations (not correct re-adaptation of the engine) led only to a mess and confusion and/or incorrect adaptations. For example, in these two menus, “Mixture adaptations” and “.. adaptation values of fuel system”, – how to understand which data of which adaptations corresponds to what? I expect that the situation with these engines will be similar – some “specialists” will delete adaptation groups at their discretion, and… Will enjoy the “fruits” of their actions;
b. I would be happy for the “All adaptations except Increment wheel” options menu. In case when/if the crankshaft hub is not repaired, its re-adaptation could be skipped. But no – there is no such a choice. So I will keep to the classic – re-adaptation of the engine.
Repeatedly I want to note a complete FAIL with putting the car to sleep after deleting the adaptations. The vehicle should be locked; the key should be placed at least 2 meters from the car, then wait till 30 minutes. Nightmare! What 30 minutes? How can we know when/that the vehicle has been “put to sleep”?
The manufacturer really was unable to make a correct hot restart of DME?
This time I allowed myself to do with starting a new driving session (Ignition OFF/Ignition ON/Engine ON) because my experience says that Bosch DMEs are “simple” enough, and nothing fatal will happen if the car will not be put to sleep.
Returning to the flywheel adaptations.
In addition to the option to adapt this hub (more accurately – this option/function is not hidden anymore), an additional option has appeared – ”check the status of the Increment wheel adaptation”. When choosing this option, a mystical parameter (number) is initially displayed on the next step – conclusion, are/are not the adaptations of the flywheel performed correctly. Spending one day achieving the flywheel adaptations procedure, I repeatedly have initial findings.
a. status description “The read-out increment wheel adaptations has a valid value” can not be trusted! Even after deleting the flywheel adaptations (and confirmation of the fact of deleting), ISTA displays this status as a “valid value”. However, DME has not a clue regarding the performance of this hub! There may be some conditions (DME identified conditions, that/when it is not possible to balance the flywheel and/or there are other problems, for example, with the plausibility of the sensor signal), when DME “changes” its mind, but – the status is displayed incorrectly in the basic situations, so my verdict is harsh – forget this menu!
b. default value after deleting the adaptations is 513;
c. creation of the flywheel adaptations for these engines happens in the range up to 3100RPM. The threshold of the adaptation confirmation gradually rises from 1600 RPM to 3100 RPM. Accordingly, the adaptations have to be performed in the range of relatively low RPM: on the 6th gear; in the Overrun mode, gradually slowing down from 110 .. 130 km/h. To reach a quality result (which is close to 1150 .. 1200), at least 5 cycles (each of 10+ seconds) on the quality road surface should be performed;
d. it looks that for these DME, there is no one fixed (internal) learnbit, which means the status of the flywheel adaptation; the reaction of the DME to un-adapted flywheel also is not as critical as, for example, for MSD80. The measure of quality for flywheel adaptations – analog values, which we can see in ISTA. The higher the value, the better the flywheel is adapted. Quality measure: in the Overrun mode, the difference of the adaptation values of the actual cycle from previously specified average adaptation values. The closer the newer data to the previously measured/averaged, the better the adaptations have been performed. The maximal value is around 1200;
e. if, for some reason (for example, uneven road), DME notices an increased difference of short-term value adaptations from the previously specified DME restores forced re-adaptation of the flywheel. For this reason, don’t be surprised that the quality value of the flywheel adaptation fluctuates and tends to “drop” after driving on the uneven road or driving with poorly balanced wheels;
f. data of the flywheel adaptations are forcibly restored, finishing/starting the driving session.
Several notes regarding this functionality
Disclaimer: The manufacturer knows accurate performance algorithms only; particular nuances are mentioned as assumptions based on the observations.
Here is how the Overrun mode with an un-adapted flywheel looks:
In the image, we see:
a. till the 86th second, RPM (blue line) drops to 1600 RPM, the efficiency of cylinders is not evened out;
b. 61st to 65th second (RPM overreaches 3100), the behaviors of the flywheel hub are strange. The efficiency of cylinders is creating “bumps”, which do not correspond to the actual situation (data below/above this RPM range);
c. till the 65th second, the flywheel adaptations are not created (due to high RPM).
Obviously, above 3100 RPM, the resource of the CPU does not allow to precisely determine the mechanical efficiency of each cylinder; in this range of RPM, the changes of the flywheel speed are actually used only to detect misfires (functionality corresponds to the description).
Here is how the adapted flywheel looks: already, since 387th second (RPM drops below 3100), we see the evening of the cylinder performance. And we clearly see that the red and blue lines (data of 3th and 4th cylinders) are not “above 0”. The difference is fundamental!
And in this image, we can better see the range of 2500 .. 3000 RPM of the adapted flywheel (220th till 230th seconds):
Maximal value of the flywheel adaptation, which I managed to reach: