Updated 10-5-11 The MBE 912 ecu I put this page together in the hope that it may help other users of these ecu's and who like myself have trawled the internet for information without much success. The lack of information prompted/forced me to look into it further and work out how to achieve what i needed which was initially to change the rev limit and introduce an input to retard the timing for nitrous use. Had i been able to find the information below, it would have saved me a great deal of time!. New, live data reader available for the mbe 912 and 906 ecu's. As there doesn't appear to any software available to read live data from the serial port on the 912 ecu (mbe easimap 4,5 or 6 doesn't support the 912), i've written my own small program. Click on the screen shot to the left to see the live data available, reading an ignition only 912 ecu. This is invaluable information for checking the operation or fault finding an ecu and sensors. The software has been installed and tested on pc's running Windows 98, ME, XP, Vista and 7. The minimum is a screen of 600x800 and 500mhz processor but any pc running xp or newer will exceed that easily!. Contact me for more information. The MBE 912 ecu is from the early 90's, but despite it's age there's still many being used. In it's day the ecu was one of the most popular after market ecu's available and very popular in racing or engine transplants enabling ignition/injection control on most engines. There's numerous versions of the ecu and software, but the 2 main versions to be aware of are the ignition only version and the ignition + injection version. An ignition only version doesn't have the components fitted on the pcb for the injection control or air temp input otherwise it's identical. The most obvious visible component is the output driver for the injectors, the ignition only version has 2 power drivers fitted, the injection has 3. On the right is a picture of the pcb from an ignition only ecu and on the far right is an injection and ignition ecu (without eprom fitted), note the additional 3rd power driver. Many people now feel that this version of the ecu is to far out of date, not easy to program and irreparable. This isn't entirely true though:- The ecu is dated, but it's still got all the features of far newer ecu's. Probably the only thing the ecu doesn't have as an option is sequential injection, it only supports banked. The program/software/maps are burned into a 27c256 eprom, so any program/mapping changes means burning a blank chip. This requires the use of a UV box to erase the chip (after it's first been read/saved!) and an eprom reader/writer to program the blank chip. Not as handy as a direct connection between pc and ecu but certainly not impossible. About the only failure in these ecu's is the output drivers. These are ST VB020, a 5 pin driver specifically designed for ignition systems in cars. The biggest cause of these drivers failing is having the coil dwell time set to long which over heats the drivers leading to failure. These drivers are obsolete now and aren't generally available from regular component suppliers such as RS or Farnell, but they are available from specialists component suppliers. They do charge a premium for the devices though, the last few I bought cost about £20 each, but that's still far less than a new ecu!. Now for the more technical aspects. The connection diagram is still available to download from the SBD website (link below) but that's all and no other support is available any where that I know of. Originally some software call Acetest was used with these ecu's but i've been unable to source a copy from anywhere. The ecu's main connection is by a 15 way connector. Pin Connection:- 1 Electronics Ground 2 ECU Supply +12v 3 Ignition Drive 1 4 Power Ground 2 (braided) 5 Throttle Reference (5v out) 6 Speed Signal 7 Air Temperature Signal 8 Coolant Temperature Signal 9 Power Ground 1 (braided) 10 Ignition Drive 2 11 Injection Drive 12 Speed Return 13 Tacho Signal 14 Fuel Pump or Gearshift Light Output 15 Throttle Signal The main 15 way connector on the 912 ecu. The pin numbers are marked on the connector, but the bottom left is number 1, counting along to the bottom right which is pin 8 , then starting at pin 9 on the top left and finishing at pin 15 at the top right. Most of the maps and settings can be adjusted by editing the hex file after reading the eprom, if you know where to look, eg:- The start of the ignition map is located at address/line 5000 (0 rpm), with 5000 - 500F being the 16 points across the throttle pot, 5010 is 250 rpm, 5020 is 500 rpm and so on. The actual timing value is the hex value shown, converted into decimal and divided by 4.25. So if for example address 50F7 has the hex value of 88, then at 3750 rpm, the ignition advance is 32 deg BTDC. The fuel map starts at 5800 and works in the same way (throttle/rpm points). Crank trigger wheel selection is at 6ADD and 23h is 32-1, 3Ah is 60-2. Engine code is at 6ADE. Ignition drive is at 618A. Distributor option is at 618B. Programmable output selection is at 6CC3. Rev limit is at 69D4 and 69D5 for the soft cut, 69D6 and 69D7 for the hard cut. Etc etc The chip comment is located at 0020 in the 912, (read in hex/ASCII)and quite often starts with 'Acetest'. This method isn't really necessary though, if the eprom is read and saved as a binary file, then opened in Easimap 4 or 5 (available to download from SBD) as the chip file. Easimap 4 requires the file to have an extension of .ecc, so rename the file with .ecc on the end and it will open it. Set the configuration file to 956aa46a.ecf, or 967ba46a.ec2 respectively. Whilst these are referencing newer versions of ecu with more features/options, all the maps and settings available in the 912 can be adjusted. Don't try and adjust a feature that the 912 ecu didn't support or have. It won't work!. The chip comment is also in a different location/address in the 956/967 ecu's so don't change it in the 912 ecu using easimap (it's part of the software code). Some of the more useful ones that are there;- Ignition map, fuel map, hard/soft rev limits, dwell, throttle points/throttle pot map, coolant temp calibration/map/timing+fuel offsets, air temp (injection ecu only unless missing components added on pcb) calibration/map/timing+fuel offsets, programmable output, plus of course the basic engine settings such as the trigger wheel (36-1 or 60-2), distributor/distributor less, coil drivers inside/outside ecu, crank off sets etc etc. This all meant that changing the rev limit was quite easy now (my original goal), the retard input for nitrous use took a bit more. The plan was to use the unused air temp input on the ignition only ecu (i use the ecu on a N/A Cosworth running on carbs)and calibrate the input and temp/ignition map for a variable retard linked to the nitrous controller. This was made a little more complicated by the ignition only ecu not having the air temp input operational on the pcb with the relevant components omitted from the pcb!. With some R+D and comparing the air temp input to the water temp input, the necessary components can be fitted/changed. After all that, some versions of the 912 software don't even read the input, but most do and over the last few years i've been collecting software/maps. The earlier MBE 906 ecu is the for runner to the 912 and the fundamental basics are the same with the eprom and programming. I hope this info has been useful, and I'm sure your only looking at this page after doing a search of the internet for information on the ecu as I had done!!. The only other web site I found with any info related to these ecu's is here:- Conradscastle Whilst based fundamentally on the earlier 906 model, it does have more useful info than any other website I've found!. Connection/wiring diagrams and Easimap software for the ecu from SBD:- SBD If you have one of these ecu's that needs repairing, or some settings/maps changing and you don't have the equipment, please e-mail me through the contact page on this web site and i maybe able to help. Ian Oddie