Comprehensive MSS54/MSS54HP DME Information

[sda2]

Is there a disassembly publically available with the maps and routines already defined? I'm thinking about starting something like this, so that additional function could be implemented or disabled.

For example, the flash counter could propably be disabled when skipping/modifiying the funcrtion that does the lookup or write.

I know C167 quite well, but from what Ive learned with MS45 and ME9, MPC is not that complicated to work with, because it has a better decompilation implement in IDA or Ghidra.

[Chris_de]

Is there a disassembly publically available with the maps and routines already defined? I'm thinking about starting something like this, so that additional function could be implemented or disabled.

For example, the flash counter could propably be disabled when skipping/modifiying the funcrtion that does the lookup or write.

I know C167 quite well, but from what Ive learned with MS45 and ME9, MPC is not that complicated to work with, because it has a better decompilation implement in IDA or Ghidra.

I dont know such a thing, I want also to start with this process, tools are available but i failed finding a good starting point..

[gixxer]

To anyone tracking their DME information:

Anyone has this hardware number MSS54HP variant? If so, then what model year is the car?


DME/ECU Type: MSS54HP
DME Version: 211323002701-J469
Transmission Type: 6 Speed Manual
Chassis: E46
Hardware Number: 7842981


Thanks.

[sda2]

https://raw.githubusercontent.com/zarboz/BMW-XDFs/master/PDF/Siemens_MSS54_Funktionsrahmen_Deutsch.pdf

I wonder how it got there

[R3Z3N]

^Translated to English via Google Machine Learning

[cek]

My understand is the MSS54 vs MSS54HP only difference is the flash PROM chips, 256KB vs 512KB. So to convert the MSS54 board to MSS54HP, one needs to remove the 2 chips (512KB) from a S54HP then read and save the files using something like the chip programmer below, then program the files into the two new chips (512K), i.e. AM29F400BB-60SC
from https://www.mouser.com/ProductDetail...W34bxMGA%3D%3D
then solder the new programmed chips back to the S54 DME board and now it become a S54HP DME.
Have anyone done this before?

I have a line on an MSS54 but need an MSS54HP. Before I bite the bullet I need to know for sure this conversion is as easy as stated above. Can anyone confirm that this information is correct? Just replace the PROM chips?

[heinzboehmer]

I have a line on an MSS54 but need an MSS54HP. Before I bite the bullet I need to know for sure this conversion is as easy as stated above. Can anyone confirm that this information is correct? Just replace the PROM chips?

There's also some resistors: https://nam3forum.com/forums/forum/s...=2582#post2582

The pressure sensor is different too, so you either have to scale it differently in software or swap out the hardware.

[M3Dude]

Hi guys,
I am trying to code out the SAP on my E46 M3, is there a write-up anywhere that can be followed on a step-by-step basis? Also, does anyone know what the code needs to be changed to so the system is no longer searching for it? I couldn't find it in the tables...

[E46m3zcp]

I am having a hard time understanding the maps shown in the first post on this thread. One of the first steps of EFI tuning is to calibrate the volumetric efficiency table (for example, when fitting a CSL airbox or more aggressive camshafts, it increases the VE and the air-fuel ratio gets too lean, and a VE table calibration can remedy this) anyone knows how pro tuners do this on our MSS54/HP ??

[dreamdrivedrift]

Just wanted to say: THANK YOU! I was able to do something (simple) and fix my sport mode memory (which was set to always on) with the help of this thread and multiple others. Really appreciate the work of the community in creating and documenting these resources, all in their spare time. They are invaluable; and I learned a lot in the process.

[R3VM3UP]

I am having a hard time understanding the maps shown in the first post on this thread. One of the first steps of EFI tuning is to calibrate the volumetric efficiency table (for example, when fitting a CSL airbox or more aggressive camshafts, it increases the VE and the air-fuel ratio gets too lean, and a VE table calibration can remedy this) anyone knows how pro tuners do this on our MSS54/HP ??

Non CSL software uses the MAF to essentially 'directly' measure airflow. The CSL runs primarily alpha N with some sort of compensation from the MAP sensor on the air rail. I'd imagine the pulsations in the MAP rail require significant filtering due to the small volume of the rail and proximity to the ports, so it cannot be used as the primary air charge estimation method. The main alpha-N VE table is KF_RF_N_AQ_REL, which is a function of engine speed and relative throttle opening.

KF = map
RF = relative filling
N = engine speed
AQ_REL = relative cross sectional opening

[sapote]

https://raw.githubusercontent.com/za...en_Deutsch.pdf

I wonder how it got there

Wow, this document seems to be a detail DME control software block diagram and theory! All we need is the "C" source code.
Or have anyone used a compiler or assemble to convert the binary file to 68376 assembly codes? C source is perfect but I am happy to work with assembly codes.

[sapote]

There's also some resistors: https://nam3forum.com/forums/forum/s...=2582#post2582

The pressure sensor is different too, so you either have to scale it differently in software or swap out the hardware.

The ambient pressure sensor is used only for CSL as the DME needs to interpret the MAP sensor in the CSL intake, and so for non-CSL I don't think it's matter. No?