M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine management => Topic started by: cristimm on September 07, 2017, 02:42:40 AM
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Hi all, I would like to write a DIY about how to tune yourself the M42 ECU. I will come back with details if people are interested.
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I'd like to see that myself. I like the features of Motronic 1.7, but I'd love to see if your techniques can also be used on later Motronics, like 3.3.
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Hi all, I would like to write a DIY about how to tune yourself the M42 ECU. I will come back with details if people are interested.
Yes please.
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OK, let's start with some needed tools. Besides usual screwdrivers and sockets that any diy-er already has you will also need the following:
1. Two pieces of EPROMs (one to have it on the car ant the other to work as a spare). Any 27F512 will work but I recommend getting the re-writable SST27SF512 which can be erased and reused. (most M42s use this chip but it might be good to double check first by opening the ECU, remove the label from the chip and see exactly what's in there).
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2. An EPROM / PIC / ATMEL programmer that is able to write the above EEPROM. I recommend the relatively cheap Genius G540 from ebay. There are cheaper options or even diy ones that can be made for a couple of bucks but imo they do not worth the trouble.
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Any updates on this? I'm very much interested to be able to tune my car by myself.
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Yes, let's go ahead with needed software.
You will need:
1. A good hex editor (I use UltraEdit https://www.ultraedit.com/downloads/ )
2. TunerPro http://www.tunerpro.net/ - normal version is enough for our purpose (not realtime)
3. You must have original binary either by reading it directly from your chip using the EPROM programmer or by downloading it from internet (first choice it is best because it will retain original serial numbers but the downloaded ones will work too)
4. Find the .xdf file for your specific bin - this is a definition file which translate the data from the .bin into a human readable form like scalars, tables (maps).
For no 3 and 4 a good start is http://www.tunerpro.net/downloadBinDefs.htm#BMW and other chip tuning enthusiast forums.
For my specific engine ecu 0261 200 950 I could not found the exact xdf but I was lucky to find the .xdf for a newer software version (990) on the page above. BMW_990_318i_soft070.xdf. Tip: search for last 3 digits written on the label just under BOSCH brand 0261 200 950 in my case. I have found by trying that 990 version of software is working on ...950 ecu. :)