[Will_460cs]

Noxem - installed for over a year now working fine for me

[Yurii54]

Hello!
I want to continue the topic.
The NOx sensor gives three signals to the ECU (not counting the error status data, etc. - we don't care about them yet).
The NOx signal does not directly affect the formation of the regeneration signal and desulfurization of the catalyst. The actual amount of NOx in ppm is compared with the amount of modeled emissions, taking into account the NOx storage capacity of the catalyst. If the actual emissions are greater than the modeled ones, then the aging factor is introduced, and the capacity of the catalyst decreases. Based on the capacity minus the passed NOx molecules (calculated from the mass amount of air and fuel, its ratio), requests for regeneration are generated!
Based on aging and other indications, the catalyst sulfate is modeled and appropriate desulfurization request.
The linear signal from the NOx sensor during desulphation determines rich exhaust gases, and the model reduces the amount of contamination of the catalyst - we are not interested in this either!
Binary signal of NOx sensor - is responsible for the regeneration process. This signal is interesting to us! ECU slightly depletes the fuel in order to "blow" the catalyst from NOx compounds, and here the algorithm for n53 (two catalysts) and n43 (one catalyst) is slightly different, but the essence is this: the binary sensor should see rich exhaust gases, i.e. with a slightly lean fuel mixture, the ability of the catalyst to combine with oxygen and oxides is checked.
That is, the readings of the binary lambda are very important, as is its switching time.
Now let's move on to the important part, this is the firmware!: To activate the calculations (not turn on the layer-by-layer mode) it is important: EGR should work, there are no misfires and ECU RECEIVES DATA FROM THE NOx SENSOR! (what data is not important now, the main thing is that there is no error on the can-bus)!
The firmware has many possibilities to expand the tolerances for the incoming data of the NOx sensor, and also to increase the "model" NOx storage capacity to very large values.
also in the firmware you can register as constants the data "virtually" received from the NOx sensor. For example, always 1 ppm!
You will ask me: "Why haven't you done the work without the sensor yet, and why write here?", I will answer: the thing is that in order to make such firmware I have to check, debug, test, on my car! And here I have a problem, even with a fully working "new" NOx sensor, a serviceable engine (no errors!), and no misfires and other problems that could prohibit calculations (as I wrote earlier) - DME does not want to turn on other modes at all! Only lambda = 1. Resetting adaptations, resetting the sensor, resetting the catalyst - does not solve the problem!
I have documentation of the Continental MSD80 level (the one with 9500 pages) and documentation of the BMW level (another 3500 pages), I have knowledge in programming the microcontroller, assembler. I have an understanding of the internal combustion engine operation - of course, not the same as chip tuners!
I need help to make it work in all modes in the standard configuration! Then I will be able to make a firmware - even with a non-working sensor activate all modes!

[Schomosport]

Hi Yurri, all the best with this, please update when you have more.

Unfortunately there is nothing I can contribute as you are miles ahead of me in your understanding.

[jirka330i]

Originally Posted by Yurii54

Hello!
I want to continue the topic.
The NOx sensor gives three signals to the ECU (not counting the error status data, etc. - we don't care about them yet).
The NOx signal does not directly affect the formation of the regeneration signal and desulfurization of the catalyst. The actual amount of NOx in ppm is compared with the amount of modeled emissions, taking into account the NOx storage capacity of the catalyst. If the actual emissions are greater than the modeled ones, then the aging factor is introduced, and the capacity of the catalyst decreases. Based on the capacity minus the passed NOx molecules (calculated from the mass amount of air and fuel, its ratio), requests for regeneration are generated!
Based on aging and other indications, the catalyst sulfate is modeled and appropriate desulfurization request.
The linear signal from the NOx sensor during desulphation determines rich exhaust gases, and the model reduces the amount of contamination of the catalyst - we are not interested in this either!
Binary signal of NOx sensor - is responsible for the regeneration process. This signal is interesting to us! ECU slightly depletes the fuel in order to "blow" the catalyst from NOx compounds, and here the algorithm for n53 (two catalysts) and n43 (one catalyst) is slightly different, but the essence is this: the binary sensor should see rich exhaust gases, i.e. with a slightly lean fuel mixture, the ability of the catalyst to combine with oxygen and oxides is checked.
That is, the readings of the binary lambda are very important, as is its switching time.
Now let's move on to the important part, this is the firmware!: To activate the calculations (not turn on the layer-by-layer mode) it is important: EGR should work, there are no misfires and ECU RECEIVES DATA FROM THE NOx SENSOR! (what data is not important now, the main thing is that there is no error on the can-bus)!
The firmware has many possibilities to expand the tolerances for the incoming data of the NOx sensor, and also to increase the "model" NOx storage capacity to very large values.
also in the firmware you can register as constants the data "virtually" received from the NOx sensor. For example, always 1 ppm!
You will ask me: "Why haven't you done the work without the sensor yet, and why write here?", I will answer: the thing is that in order to make such firmware I have to check, debug, test, on my car! And here I have a problem, even with a fully working "new" NOx sensor, a serviceable engine (no errors!), and no misfires and other problems that could prohibit calculations (as I wrote earlier) - DME does not want to turn on other modes at all! Only lambda = 1. Resetting adaptations, resetting the sensor, resetting the catalyst - does not solve the problem!
I have documentation of the Continental MSD80 level (the one with 9500 pages) and documentation of the BMW level (another 3500 pages), I have knowledge in programming the microcontroller, assembler. I have an understanding of the internal combustion engine operation - of course, not the same as chip tuners!
I need help to make it work in all modes in the standard configuration! Then I will be able to make a firmware - even with a non-working sensor activate all modes!

Hi Yuri
Good summary.... thanks! It seems you are getting very close to a clean software solution of the N53 NOX; however a challenge of keeping correct mode switching between homogenous and stratified still means a lot of experimenting (few years ago, with a help of an advanced bmw engine tuner we got to the point where a remap of msd80 allowed- NOX sensor cutoff and proper running but only in homogenous
I still think that one of the issues why your car does not switch modes even after installation of new NOX senzor (from the pictures you send to me it looks original sensor gen 05) could be problem with thermostat ot electric water pump- as far as I know DME stops switch of the modes (besides the reason you mention) even if the temperature profiles of the engines are not being met (try to google for details but n53 is a bit of demanding bitch in that respect); and also discrepencies in the operational parametres can cause restriction on switching into stratified. Also, some older versions of firmware of msd80 (especialy those up to 2012) are a bit more restrictive... so make sure you have the latest msd80 firmware which is in the I-level from 2018
It would be great if you are able to complete a full rework of msd80 firmware to be able to work without nox sensor and keep mode switching, you have been able to go further than myself about 5 years ago ( I have arrived to a point that realizing how many n53 are going to be alive in few years, versus time needed to complete all experiments proving it works, led me to a decision to leave the "project")

In between, I have arrived to a "good value for the money" solution to keep original bmw nox alive in my own n53 and for friends. I am able to get original NGK nox probe NS11a for around 150 euro and it can be easily connected (8wires) to any generation of bmw nox sensor (the box with electronics never dies according to my 10years of experience) for n53; that probe is a part of bmw sensors for actual BMW Gxx (standar price od them exceeds 600 euro)

[Yurii54]

Hello!
Yes, I had problems with the water pump two years ago, I changed it to a new one and also changed the thermostat! Jiri there are no problems with the cooling system, because after resetting all adaptations, the temperature very quickly rises to +-108 degrees.
But after some time the temperature decreases and the ECU maintains 90 degrees - and as a person from a site we know writes, the ECU has switched to MAP mode!
And I did tests to check the pumps and thermostat, everything works!
About the problem: as the Internet writes, if there are no critical faults, for a short time until the system understands that something is wrong with NOx, then the modes should switch!
I have: No errors. The NOx sensor works, communicates, shows ppm, lin Lamb, bin Lamb, no misfires, I have tested the systems (water pump, thermostat, radiator flaps, etc.) and everything goes without errors. I have reset all adaptations, trained using videos on YouTube and instructions on the website. It does not switch modes, even for a moment!
I am asking for advice on what other systems to check that may be affected by (prohibition) modes?
Jiri, I agree that the original and standard solution is the best! But, the car gets older every year, and soon (maybe like mine, mileage over 300,000 km) problems may arise (I don't know, either I have a problem in the NOx system, or in something else) when replacing the sensor does not help! And it would be good to have a solution!
Therefore, I am not asking for a solution to change the firmware, at this stage I am asking for help to start the system in normal mode with a standard sensor!

[jirka330i]

Originally Posted by Yurii54

Hello!
Yes, I had problems with the water pump two years ago, I changed it to a new one and also changed the thermostat! Jiri there are no problems with the cooling system, because after resetting all adaptations, the temperature very quickly rises to +-108 degrees.
But after some time the temperature decreases and the ECU maintains 90 degrees - and as a person from a site we know writes, the ECU has switched to MAP mode!
And I did tests to check the pumps and thermostat, everything works!
About the problem: as the Internet writes, if there are no critical faults, for a short time until the system understands that something is wrong with NOx, then the modes should switch!
I have: No errors. The NOx sensor works, communicates, shows ppm, lin Lamb, bin Lamb, no misfires, I have tested the systems (water pump, thermostat, radiator flaps, etc.) and everything goes without errors. I have reset all adaptations, trained using videos on YouTube and instructions on the website. It does not switch modes, even for a moment!
I am asking for advice on what other systems to check that may be affected by (prohibition) modes?
Jiri, I agree that the original and standard solution is the best! But, the car gets older every year, and soon (maybe like mine, mileage over 300,000 km) problems may arise (I don't know, either I have a problem in the NOx system, or in something else) when replacing the sensor does not help! And it would be good to have a solution!
Therefore, I am not asking for a solution to change the firmware, at this stage I am asking for help to start the system in normal mode with a standard sensor!

Well, as I told you- this would require a proper deep dive diag with INPA/ISTA to learn what are the exact parametres of engine in idle, low load and high load... I am 90% sure that one of the parametres outside the range restricts mode switching even with newly installed bmw nox sensor
The temperatures around 108 degrees are allright but 90 degrees sounds strange to me... in the first step I would probably focus on finding why that happens
Good luck and keep us informed!

[Yurii54]

I will add information! It is cold here now, winter! I did an experiment, turned off the heater, and waited. The engine temperature rose to 108 degrees, the fan turned on and cooled down to 100 degrees, and so on cyclically! When I turned on the heater, the temperature smoothly dropped to 90 degrees.
I think this is normal, the cooling system is working properly!? 🤔