[sjed]

TLDR; On my N53 engine in my F11 the NOX sensor is failing, causing issues with stratified charge. My options are:

1. BMW OEM sensor (expensive)
   
2. Soldering a new NGK NS11A sensor (cheaper, high succes rate)
   
3. Buying NOXEM (mixed reviews, works but support is not great)
   
4. Software coding (controversial, but some success stories)

Does anyone have experience with software coding for this issue?

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For those not familiar, the N53 engine is a non-turbo engine that was used in the F11 before the N20 took over and the N54/N55 stepped in. To use all three injection modes (with stratified charge being the one reducing fuel consumption), it needs healthy injectors, plugs, and a NOx sensor.

The first two have been taken care of, with all index 11 injectors and the right type of plug and coil pack. Now, my NOx sensor is on the way out and it drops out of stratified charge after a while (confirmed by observing Lambda values).

My options:

1. BMW OEM: From what I understand, the NOx ECU is very likely still fine, so this would be a bit of a waste of money.
   
2. Soldering a new NGK NS11A NOx sensor to the ECU: The sensor is 1/5th the cost of buying BMW OEM. Most who have done this have been successful in restoring stratified charge.
   
3. Buying NOXEM: I hear mixed stories about their support, and from experience, I am also not too satisfied with their replies.
   
4. Software coding: Bimmerprofs say this is a bad idea, as the sensor also communicates over a LINBUS, which can't be simulated in the ECU. However, I have also read posts on multiple forums where software coding did restore all three modes.

So my question to you is, does anyone have experience with software coding? I have found two companies here that claim they can do it. I honestly can't be bothered too much with the NOx the car will produce in stratified charge and keep replacing the sensor and at some point the catalyst, so it would be the preferred option.

[Gnoe]

I'm not familiar with your option 2 and 4 and no answer to you question, but why not go for option 3? The Noxem eliminates several factors that cause running/fuel consumption issues. Be aware also that your NOx cat converter will be EoL under 200k KM and does not need replacement when you have the Noxem. A new cat converter is likely 1/3 the worth of you car, or even more.

Bimmerprofs (the expertise site behind the Noxem) is a 1 man shop, but the guy (Kaspars) has fundamental understanding of this type of BMW engines.
I installed the Noxem a few years ago and no issues with injection modes since then.

I also did the remote analysis (based on INPA screens/video) and was adequately supported. It helped me very well to identify issues with the car that normal workshops or BMW dealers would not even see.

[bojo_ri]

Sorry for the revive almost a year later.

TL;DR don't code out the injector, it's essential for not only fuel economy but proper running of the engine.
Kaspars from Bimmerprofs is an absolute legend when it comes to the N53, I read a lot of his blogs and from what I read he can't stop bashing the cheap solutions on these N53s, with very good reason - these are overengineered complex engines and anything short of well versed mechanics in BMW can work on them.

I recently bought a 325i which war running rough with 4 no-name injectors and 2 leaking index 09 injectors.
I exchanged them all with index11 as well as proper coils and plugs and coding injectors and resetting adaptations, only to then have the engine perform badly with no change - poor throttle response, shivering, hunting idle, hot or cold didn't matter etc. Did a smoke test so no vacuum leaks.

Then I started to get suspicious about the NOx system as the ECU had no errors and I was right, it was completely disconnected from the harness and it was an OEM part from bmw.
So as it turned out, when I spoke to the previous owner before buying the car, he said that when they changed the 4 no name injectors they did the programing, which I (in retrospect wrongly assumed) he meant coding the injectors, but what they actually did is code out the sensor entirely as it was probably failing along with the injectors (or because of them as leaky injectors can destroy the NOx sensor)

So I ended up ordering the NOEM from bimmerprofs last week and we'll see the results of soon enough.

P.S. If someone coded out the NOx sensor on your car and you want it back, you'll have to re-flash your DME with WinKFP or ISTA-P to get it to work again, so there's the risk of bricking your DME on top of your NOx troubles.

Would be interested to hear what you did in the end.