This time a good example, how BMW acted after an unsuccessful experience with N43/N53 series engines of E series cars.
The N43/N53 engine family of the E series cars was famous with regular error messages regarding all possible systems, especially: regarding the NOx system and uneven performance of the engine. The error message regarding uneven performance (3104) was recorded even when driving on the uneven road!
How do BMW F series cars act?
Example
The owner of the BMW F10 with the N53 series engine approached me. The car has the error message regarding the NOx sensor, the insufficient performance of the NOx catalytic converter was detected (mileage of the car: over 270’000km), a complete crash of the adaptations of the injectors and performance of the cylinders. NOXEM was installed, and the car was returned to the owner for the creation of the adaptations. After several hundreds of km, the owner reported, that the car performs very unevenly (not taking into account new adaptations, assuming that they are correct).
When starting the luke-warm engine (its temperature around 40oC), I detected, that the engine runs unevenly:
- not taking into account the voltage of the Lambda probes 1.95 .. 2.05V (so: the Lambda entire whole bank is correct – around 1.00);
- mechanical efficiency of cylinders indicates increased short-term differences from 0 (also – there is no permanent disbalance, which means: individual fuel mixture of cylinders is correct).
Regular misfires in almost all cylinders, despite the correct fuel mixture?
It’s time to check the ignition coils and spark plugs. According to the owner, the car was recently maintained in another service center, but – what does this maintenance include, who knows…
And so – check the appearance of the ignition coils! The damaged places, where the current leakage has happened, marked with red.
And so looks the spark plugs.
It is clear, that the “maintenance” did not include nor replacement of the spark plugs, neither evaluation of the condition of the ignition coils (and in this case, it should be a replacement, not only evaluation)! It is completely clear, that the spark plugs are not replaced 25’000km before, not 50’000km before, and not even 75’000km before!
It is self-evident, that both ignition coils and spark plugs have to be replaced. But another aspect is even more interesting. I allowed the engine to run in idle for only several minutes. As I already mentioned, the shivering of the engine was extreme, misfires – regular (the engine was shivering continuously).
I decided to check the misfire counters: 
Here: for 5 cylinders (of 6) misfire counters are 15.. 39! In total more than 100 events! At the same time – no error messages regarding the uneven performance of the engine, misfires, ignition problems!
The situation – completely opposite the E series (MSD80/81). DME of E series vehicle would record the error messages immediately: regarding misfires (regarding “most popular” cylinders, and also the error message regarding misfire of several cylinders, because of the total number of the misfires is crushing), the error message 3104, if the engine would try to perform in the Stratified charge.
It is clear, that the normal performance of the Stratified charge is not possible with such ignition components (in the images above) – misfires are guaranteed. It is clear, that when the engine warms up, it switches from Stratified charge to the Homoegenus lean, from it – to the Homogeneous (emergency) mode. But – no error messages!
Of course, BMW can “breath easily” – less reclamation. But – the problem of uneven performance has not disappeared. Even more – driving for a long while with such misfire, all exhaust system – CO catalytic converters, NOx catalytic converter, Lambda probes, NOx sensor – is getting damaged!
