MBE Ecu Information Updated 27-1-2016
New, Lcd Mbe ecu reader;-

The reader works with Mbe ecu's- 906, 912, 956, 967, 941, 970 and 975 with serial ports. The reader measures 111x57x22mm and the only connection required is the serial port on the ecu (approx 1m of cable with serial plug supplied).

Upon connection/powering up the ecu, the first screen displays the ecu ID code and the ecu pin code if set (the early 906 and 912 do not have ID's or pin codes so N/A is displayed) for 2 seconds. Knowing the pin code is invaluable if you have a locked ecu and want to make any map changes or you take the car for mapping at a rolling road that doesn't know the pin code!.

The main screen displays the current;- Engine rpm, Ignition timing, Injector ms, Actual map ignition timing (before compensations), Actual map Injector ms (before compensations), Coolant temperature, TPS voltage, TPS site, Air temperature (not on the 906 ecu) and battery voltage. This information is invaluable for fault finding on the early 906 and 912 ecu's as they're not compatible with the mbe easimap software. Also very handy for the 956/967/941/970 as it's much quicker and easier to use than starting up and connecting a pc for quick checks.

The display also works with the Mini Sport SPI ecu (Mbe 939-C ecu)

For more information, price etc, contact me.
The ecu display will also normally be available on ebay.

Many of these units have been sold now primarily to gain access to pin coded ecu's. There's a few reasons that a pin code has been set by a tuner/garage/rolling road, sometimes to keep their work and strategy's secret, sometimes to keep the end user from tinkering with the maps without knowing what they're doing and of course another reason is to ensure that the user has to return with the engine/car for any future work!. Please use common sense if you use this device to gain access to an ecu.

By default Ecu's supplied by Mbe normally have no code set, whilst others supplied by one of their main distributes SBD usually have 1111 as the pin code. Subsequently any 4 digit code could have been set though.
Mbe 906 ecu;-

This ecu is from around the year 1990, even so they're still being used. The 906 ecu is best suited to ignition only installations using wasted spark and carbs. It does have the option to run batch fired injection but the ignition must then use a single coil and distributor. The ecu is quite basic compared with today's ecu's but can still work well and is huge step forward on any points/distributor set-up. It has inputs for tps, coolant temperature and of course crank trigger, outputs are ignition/injection, tacho and 1 programmable output which is normally used for a shift light. Most are used in the most basic set-up with just a crank sensor input and coil pack for wasted spark ignition on an engine running carbs. The maps and settings are stored in the eprom. Programming, faults and repairs are basically the same as for Mbe 912 ecu below.

Pictured on the left is a 906 ecu which has just had an output driver replaced and the eprom reprogrammed with a new rev limit.

For repairs, programming etc contact me.
Mbe 912 ecu;-

The 912 ecu was the successor to 906 above with more inputs/outputs and options. This ecu is from the early to mid 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 (912v1/v2/v3), 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 extra output driver (VB020 drivers) 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.
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 fairly straight forward with the correct equipment. The most common fault with these ecu's is blown output drivers (usually an ignition driver causing loss of spark on a pair of cylinders), quite often due to excessive ignition dwell time causing them to over heat.

For repairs, programming etc contact me.

Mbe 956 ecu;-

Externally the 956 ecu is identical to the 912, but internally it uses a different pcb with VB027 power drivers. Additionally the ecu can be programmed directly from a pc using the mbe easimap4 software which is much easier than the earlier 912. The pin out is identical to the 912 except for pin 4 which is the lambda input (was a ground on the 912). The 956 can be plugged straight into a 912 loom if the lambda is not needed/used and makes the upgrade very easy. Towards the last 956 ecu's produced the processor clock speed was changed from 8mhz to 16mhz. This can make quite a difference with a highly tuned engine/bike engine. The change over point was around version 956BA460 software.
As with the 912 ecu above, the ecu was supplied in both ignition only and injection/ignition (designated 956E) with the same arrangement of output drivers. Some of the ignition only ecu's only have the very basic essentials of tps input and coil driver outputs and no more. These ecu's can be upgraded to a full inj/ign ecu with all the inputs/outputs by fitting all the missing components(and changing a few) on the pcb.

Like the 912 ecu the output drivers can fail in the 956 which normally leads to no spark on a pair of cylinders (wasted spark set-up). It's very rare for the injector driver fail. Take note though that the 956 pcb is a triple layer and extreme care should be taken while replacing the drivers not to damage the connection to the center layer tracks.

For repairs, programming etc contact me.

Mbe 941/970 ecu;-

The 941 ecu was mbe's top of the line ecu in the 90's and then superseded by the 970. They use a 55 pin connector and the plugs are available from RS Components. Again these ecu's are interchangeable, but over the years the software has been updated with more and more features/options. An early 941 ecu works perfectly with software from a 970 ecu so long as the processor crystal is 16mhz or changed if it's an early 941 with an 8mhz crystal fitted.

Contact us if you require a 941 ecu upgrading to the latest 970BA623 software (and 16mhz crystal if required). Depending on which software you currently have fitted, the upgrade is well worth doing. Many more features are available and several bugs in the early software are fixed (eg overly long dwell times at idle which makes the ecu and ignition coil/s run hot). If you have the upgrade done on an early 941 (pre 941AA460 software) you'll then need to use Easimap 5 or 6 which both support the 970 ecu/software.
Internally the ecu looks more complex, but is fairly straight forward really. The ecu has far more inputs and outputs so has more power drivers and input circuitry. The advantage of these ecu's is the software the ecu runs is stored on an eprom so is easily changed/upgraded (see picture). The earliest 941 software is 941AA170 and the last software for the 970 was 970BA623 The actual chipfile (user settings/maps) is stored in the esquared chip, again on a socket. From the early 941 which used VB020 drivers the ecu's evolved to using VB027 and then later on went onto use more surface mount parts on the 970 (picture to the right), but all use the same case/socket/pin connections. The software and chipfiles used in the 941/970 are the same as the 956 ecu's but the 956 doesn't have all the inputs/outputs available to use but still has things like baro/launch control, boost compensations etc in the software and maps in the chipfile. The features that are unavailable in the 956 are just disabled or run at default values.
Depending on the software in the ecu, the ecu's are programmed with easimap4, 5 or 6.

These ecu's were also supplied to specialist car manufactures such as Tvr (usually anodized gold or blue rather than the normal black colour) and Noble. Those ecu's themselves are identical, but some of the software is bespoke for the specific applications with none standard inputs/outputs. The easimap software is not 100% compatible with some of them, but the files can be decoded and the maps edited. The Tvr ecu pictured on the left is really a regular 941 ecu (with idle control)but the software stored in the eprom is specific for the Tvr. Regular ecu's will use firmware versions such as 941BA463 where as the tvr uses a different numbering system such as 94110035. The eprom stores the firmware for the ecu as with a regular 941 or 970 ecu but the tvr version also stores the engine maps and settings. This means to change fuel or ignition maps, it's necessary to reprogram the eprom which cannot be done through the serial connection and easimap. The 2nd chip is a SRAM which is used to store adaptive maps such as fuel from the lambda inputs. These SRAM memory chips have an on board battery which normally fails after 15 - 20 years causing the engine to run very rough, often being blamed on the ecu being faulty. Replacing the chip cures the problem.
Mbe 967 ecu;-

The Mbe 967 was first released around 1999 with software 967BA463 installed. Smaller than the 941/970 ecu's but also with slightly less features with only 36 connections, and now all surface mounted components. Not as easy to update the software as the 941/970 although the basic essentials of the ecu design are similar. The output drivers are IGBT's (14N36GVL which are also used in some of the 970 ecu's) and again aren't generally available any more but better specification replacements are not hard to source. Despite the pcb having output driver temperature monitoring for the ignition drivers, they can still burn out with wiring or coil faults.

Pictured on the left is a 967 ecu which has just had an output driver replaced.

For repairs, programming etc contact me.
Mbe 975 ecu;-

The Mbe 975, a top level ecu used by several specialist car manufacturers such as Tvr, Marcos, Noble, Caterham etc. As with other ecu's from Mbe there are numerous versions of the internal pcb but most of the signal and output driver pinouts are the same. With 3 separate connectors for the loom, black plug has 32 pins, brown centre plug has 48 pins and the grey plug has 32 pins making a total of 112 pins(see picture below right). Depending on the ecu version, some use a serial connection (like the tvr version below left) and others have both the CAN bus and serial option.

Similar to the tvr version of the 941 ecu (pcb shown below left), the eprom on the socket stores the firmware for the ecu as well as the maps/settings, the SRAM in the adjacent socket stores the adaptive maps. The SRAM chip does have an internal battery which is guaranteed by the manufacturers for 10 years but generally lasts between 15 and 20 years. When it fails the car will run very badly and the ecu is often blamed as being faulty when the SRAM just needs replacing.

Centre picture below is the pcb inside a regular 975D ecu as found in the Noble, Marcos and some Caterhams etc

For repairs, programming etc contact me.
Mbe 992 ecu;-

Moving on from the 967, the 992 was next in the line from around 2003. Chipfiles in the earlier ecu's are all 32k in size, the 992 is 64k in size to cater for the many more features and settings available in these later ecu's. They are also the first to use CAN communication rather than serial/RS232 which means you need the Mbe Usb-CAN interface (Mbe 985) to program the ecu so not as easy (or cheap!) as a simple serial lead. The output drivers are VB125 devices but they're generally very reliable.

Pictured on the left is a 992 ecu pcb, and on the right the case which is basically the same as the latest Mbe 9A4 etc

For repairs, programming etc contact me.


A few general notes in no particular order (primarily for the older serial based ecu's);-

It's safer to disconnect the injectors and ignition coil when doing a full chipfile upload/download to the ecu. Sometimes the output drivers can be damaged if not because they can go into random states driving the coils or injectors during ecu programming which can burn out the output driver/s. Editing/loading individual maps/settings is ok.

The software (eg 956BA260) in the ecu's denotes several things, the first 3 digits is obviously the ecu type. The 'BA' is the options available in the ecu for crank triggers/engine types. The BA is by far the most common with the usual options of 36-1/60-2 triggers and grouped 4 engine etc, BC tends to cover other trigger wheels such as the Rover K series etc and the AA versions are the very early software versions for the 941/956 ecu's. The last 3 digits is the software version, the higher the number the later the software (ranges between about 170 to 623).

Mbe seem to do a lot of prototype software/ecu's for manufacturers, and these ecu's and software appear for sale from time to time. If it's a 941 or 970 ecu then the software can be easily swapped, a suitable chipfile loaded and everything is fine. If however it's a 956 then the software is programmed into the AN87C196 processor chip on the pcb which is soldered in place and can't be re-programmed. There are a few around like this (one software version i have seen is 966BA266) so be aware!.

Some ecu's have been custom built to suit specific input sensor types, and resistors values changed on the pcb to suit (eg the 956 ecu for the Westfield Zetec). With a 'normal' sensor connected the ecu will show totally incorrect readings/values or vise versa if regular ecu is used to replace the original. The resistors can be changed back again though.

There is a minimum cranking speed to ensure accurate timing/fueling whilst starting, but generally it's never encountered. It varies a little on which tooth pattern is used on the engine trigger wheel, with a 36-1 it's around 140rpm and with a 60-2 it's about 80rpm. These cranking speeds are very slow so unless the battery is very low/flat it's nothing to worry about. Whilst it shouldn't be a problem it's worth remembering if an engine isn't starting as it should though.

All the ecu's are designed to use high impedance injectors of around 14R. Ignition offsets fine/course are used to reference the crank sensor position relative to engine tdc. An engine such as the Vauxhall XE which retains the original crank sensor has values of 13.2 fine, 20 course and a 60-2 trigger wheel. If however an ecu is used on an engine with an after market trigger wheel then the ignition off-sets will need setting first before any other mapping takes place. The course setting must be an even number (normally 18, 20 or 22 with most crank wheel set-ups) and advances the timing by increments of 30 degrees. The fine setting is adjusted between 0-30 degrees and retards the timing which is then used to adjust in between the course setting.

Some versions of software cut the fuel if the injector duty cycle reaches 100% as a warning but this can be misinterpreted as an ecu fault because it feels like hitting the rev limiter but at a lower rpm. Of course it's better to keep the duty cycle to around 80% but miscalculations do happen!. The fuel gain adjustment is the quickest way to trim the entire fuel map if say the injectors and/or the fuel pressure changed but the fuel map may still need small tweaks in some areas.

If an engine that has been running perfectly suddenly runs very poorly (to rich or to lean) always check the throttle pot voltage/site number is correct (the value the engine was originally mapped at). Even a relatively small change can have a severe effect on the engines running, especially at idle.

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, help, problems or questions on these ecu's!. I've put this information together from the work i've done with them and what i've learnt and seen over the years.

Easimap software and some information is available from the Mbe website:-

Mbe

Connection/wiring diagrams and Easimap software for the ecu from SBD who are an Mbe distributor:-

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 contact me. I have test facility's for testing all the ecu inputs/outputs and a crank trigger simulator (all the options, not just 36-1 and 60-2) for testing the ecu's

Ian Oddie

Other Mbe Ecu's;-
Mbe 939-C ecu;-

This ecu was built for Mini Sport (Padiham) to be a direct replacement with the Rover SPI ecu in the Mini, basically an Mbe ecu inside a Rover ecu case. As far as mapping, the ecu is fundamentally the same as the 912 ecu with the maps stored in the 27c256 eprom and the date stored within the eprom file is 14th January 1994. The ecu supports most of the original Rover ecu's features including stepper motor control for idle speed, lambda input (closed loop around idle) etc, but the map input pipe on the ecu isn't used. The mapping is tps/alpha N based.
Pin Connections;-
1, +12v
2, Output A, Idle Stepper Motor
3, Output C, Idle Stepper Motor
4,
5,
6,
7,
8, TPS Input
9, TPS +5v
10, Not Used
11, +12v
12, Not Used
13, Not Used
14, Not Used
15, Not Used
16, Air Temperature Input
17, Not Used
18, Gnd
19,
20,
21,
22, Output B, Idle Stepper Motor
23, Not Used
24, Injector Ouput
25, Ignition Ouput
26, Not Used
27, Output D, Idle Stepper Motor
28, Not Used
29, Gnd
30, Gnd
31, Crank Sensor Signal
32, Gnd
33, Water Temperature Input
34, Not Used
35,
36,
The ecu uses a single VB020 driver for the ignition coil and another driver for the single injector. Standard settings in the ecu seem to be 36-2 trigger, 0v8 idle tps, 7000rpm soft cut and 7050rpm hard cut.

Mbe 909 ecu;-

Another custom Mbe ecu, model 909. Again uses mapping/software from the mbe 906/912 ecu's and within the eprom file comment line it's dated 4th November 1992. This ecu is from a Vauxhall GSI Racing 16v. As with the 912 ecu's, the eprom stores the maps/settings and if the eprom is read/saved then the file can be opened with easimap software and the settings/maps changed, saved and reprogrammed into an eprom and refitted into the ecu.