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Audi RS4 MAF on Siemens MS43 (Bosch 0 280 218 067)

80K views 99 replies 22 participants last post by  etsbonb 
#1 · (Edited)
Hello e46fanatics,

our ECU, the Siemens MS43, is limited to read 1024kg/h of air. After applying the MAF hack, this value doubles to 2048kg/h and therefor enough flow for bigger MAFs.

A cheap alternative for the HPX PMAS MAF is manufactured by Bosch with the part number 0 280 218 067 (or 0 986 280 219) and is installed on the Audi (R)S4 B5's 2.7 V6 biturbo engine and is able to measure upto 1800kg/h.

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The MAF sensor module comes preinstalled in a 3.5 inch housing and has a 5 pin connector (Audi part number 1J0973775A) with the following pinout:

  • Pin 1 - IAT sensor output (not used)
  • Pin 2 - voltage input 12V (red?)
  • Pin 3 - common ground (black)
  • Pin 4 - voltage input 5V (brown/white)
  • Pin 5 - MAF sensor output (yellow)
The IAT output on pin 1 can be connected to an aftermarket logging device to monitor the intake air temperature before compression, or in case you leave it unconnected, make sure to seal the pin in the plug, to prevent the maf from corroding like this.

Pins 2, 3 and 5 should be self explaining, you can just connect them to the OEM MAF wires, or create a new 4-wire loom and run it to the cable distribution box located under the intake manifold.

Pin 4 need a solid 5.00 volts supplyvoltage, as this is the reference for the MAF output signal. This is absolutly crucial for the MAF to work properly!

The MS43 has two integrated 5V outputs, one for the electronic accelerator pedal and one for the electronic throttlebody, which you will preferly use, because you can tap into the wire right in the distribution box.

By the way, this is pin 7 at the middle ECU connector (X60003) for the voltage U_DKG according to the manual (brown/white, 0.5mm²)
If anybody is concerned about the MAF drawing too much current, during operation it only needs 1,1mA :thumbsup:


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Now that you have the connection from the MAF to the ECU, the next part is applying the MAF hack (512k file) and editing the sensor definition (64k file) :D

You have two options to double the MAF limit:

  • First is to do it manually with a HEX editor and changing the bytes 0x3D8A3 and 0x3D8C7 from "4E" (1024kg/h) to "3E" (2048kg/h) and double the conversion in the Tuner Pro MAF table to "0.03125*X"
  • Second is downloading RomRaider and the MS43 definition .XML file, flick the switch under the "Forced Induction" section and use the special MAF table right next to it.
Either way you have to recalculate the four checksums in the 512k file, even if you use the CHK5/EWS delete File from Daniel, as this only disables the fifth checksum in the 64k file.

In addition to that, you need to set "C_MAF_KGH_R_LS_MES_MAX" to 1800kg/h.

Today I discovered, that "C_ABC_INC_MAF_MON" and many other constants lay within checksum 4's area. This means you can only edit this value in the 512k full flash. (Look over here for details)

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The user jd_improved was kind enough to share his sensor definition and allowed me to publish it in form of an Excel, respectivly CSV, file, that you can download from my Google Drive over here. Just copy and paste the new values over the existing ones :thumbsup:

I will also provide an updated 512k file with the MAF hack for all M54 engines, correct checksums and the RS4 MAF characteristic already applied and the corresponding XDF file for editing it with Tuner Pro for the lazy people. :D


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Note 1: Credits belong to Daniel_F. for his amazing files, jd_improved and volter for the Bosch characteristic and the RomRaider team for the MAF axis values!

Note 2: The RS4 MAF measures backflow in the section below 1.00 volts and therefor it's zeroed out in the table, since the MS43 can't understand .

Note 3: The XDF file published by MS43info on the 16th Feb. contains an error in the MAF voltage axis, I corrected it with the correct values from the RomRaider axis.

Note 4: This is not the holy grail, so let me know if there is room for improvement. Malfunction can happen, but that's why this board exists, let's figure this out together!



Have a nice day :craig:
 
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#56 · (Edited)
Cuz ive went through 6 MAF's on this car , where 3 OEM from my friends , 1 dealer 1 from autozone and 1 ebay ( ebay worked best but still had problems , such as it would throw fault for MAF and switch to a map without map after car restart its fine , where this sensor doesn't have such problem ( maybe its me not feeling the torque curve like it was with crap maf's before because it feels smooth now and i cant tell if its kicking right now at 3500 , but i drove the car more and im sure i actually got more hp , because rolling with 3500 rpm if I floor it , my tires brake loose even though i have traction on ( the housing is 3.5 inches since its a 3 liter car ( its not RS4 housing its literary stock modified with JB weld housing because i have so many of those maf's that dont work and ebay was the cheapest so it went for the good use ( rest mafs I already returned) ( also checked the oem wire loom for maf , has no problems as long as I can see)
 
#57 ·
The best and also the cheapest way for you is to spend the 200 bucks for an new original Siemens/VDO MAF with a good new airfilter! A MAF is a high sensitive device, which won't get better over time. I only would use new and high quality MAFs. If that don't work, the MAF is not your problem!

The whole engine management is based on the MAF parameters, so it is important to have an exact working MAF.

Only change the MAF to an another sensor if you really need it, like in FI where the stock MAF is maxed out. Also with an MAF where you have a sensor definition like the RS4 MAF you don't get as good results as with the stock MAF.

Don't fool with the MAF!!! Switching MAFs and Housings is not the way to go, you must mesasure the new sensor characteristic if you do that. The load calculation isn't as simple as it seems.
 
#58 ·
Came to report about my car and the maf , so apparently after driving the car for a while almost 2 weeks it was getting better and better , now i brake tires lose in 2nd gear if I floor gas pedal ( dont know if maf has anything to do with that ) but before i couldnt do it in 2nd , and it would barely do it in first so I think my car just needed to adapt
 
#61 ·
hi guys, after reading all this there's still a few things unclear, after changing the maf to 2048kg i cannnot change the load axis in the main fuel table, its stuck at 700mg and needs to be 1389mg, this is using rom raider. Now in tunerpro you can change the load axis but its in the 64kb file, is this ok? I thought this would have to be done in the 512kb file.
second thing is how do I go about check summing the 512kb file after the mod?
Im installing my turbo kit in the next month or so and im looking at using this mod. thanx in advance to all the people that have made tuning this ecu possible, great work!
 
#66 ·
Can anyone help me out on telling me how come on idle i have 250mg/strk? its defintely has to do with maf cuz there is nothing else that seems to be wrong , also the way the maf is set is blow through I feel like because the turbo making slight pressure ( because I can feel it on my hands a slight wind ) it reads higher MG/strk and thats why I have problems tuning my car
 
#70 ·
So right I think my timing could be off a lot , because I think when I redid it , I screwed it up because I thought all the time I had issues with timing in the engine , but it was always the maf , now im gonna go redo the timing again for the last time , try couple of files that people send me , and hopefully Ill get it to work before monday , today is my bday and im gonna tear into my engine because I WANNA FCKING RAGE AND DO BURNOUTS AND ALL OF THAT , but cant , so in few hours my timing should be redone. once Complete ill upload files and try them out. And if it works I wanna make a tab in WIKI about RS4 maf , with b30 file and accodring xdf so people dont have to go through trouble like I did. Ill post a file for a turbo car ( but its incomplete because I couldnt tune past 10psi /5200rpm) I have a dyno scheduled on 16th , and I need this running up to 25 psi with no problems , at least 20 be good for now ) Just hang in there guys.
 
#85 ·
Theoretically, you can put it how ever you want. But most people run as part of the charge pipe, before the throttle body , and most people don’t use recirculating blow off valves, but a regular atmospheric one. Either way, if recirculating, make sure the air gets recirculated back before the maf; so the maf can see the change in air. Same thing for a atmospheric BOV, make sure it before the maf.




Sent from my iPhone using E46Fanatics mobile app
 
#87 ·
"
In addition to that, you need to (suppress the MAF DTCs with zeroing "C_ABC_INC_MAF" and "C_ABC_INC_MAF_MON",) set "C_MAF_KGH_R_LS_MES_MAX" to 1800kg/h and C_MAF_MAX to 1389kg/h (the highest value possible for this constant). "

Anyone know what these are for MS42? The current definition file for tuner pro is in german
 
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