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Info on the UK Honda Civic 1.8 VTI

Modifications > Motor > Engine > Ecu

Ecu


It is roumoured that the MB6 was intended to use the P72 ecu found in older Honda's, as it is labeled with P72 in the engine bay.  However, even though the car got given a mildly tuned P9K it is not impossible to run on a more aggresive JDM P72 (003 AS) used in the Integra Si (92-95).  The best bit is that the P72 is chipable, therefore it can be re-mapped to extract more power from other mods you may have done to your car and it also allows you to disable the 115mph speed limiter.


The standard ecu (P9K) is of the OBD2 type but oddly it still has OBD1 style plugs. So, if you are not into using piggyback ecu's then a great alternative is to replace the P9K for a JDM P72.  A slight modification to the A plug is required to fit in the ECU.  This is done by simply shaving two ribs from the 'A' plug (this will not affect reverting back to the original ecu).


Of course, simply replacing the ecu is not enough to make it work and modifications to the main board is required in order to restore the VTEC changeover and getting the IAB's (dual butterflies) to work properly. But before you start, it might be a good idea to check what codes are being thrown - You should only get codes 20, 22 & 23 which code 22 will be dealt with by bridging the VTEC Solenoid Valve to the VTEC Oil Pressure Switch (as shown below), codes 20 & 23 can be dealt during the chipping process with a rom editor.

To get the VTEC to engage bridge pins A4 & D6 and for the IAB's you will need to bridge pins A17 & A19... as shown in the picture below


Ok... so now the P72 is modded enough to work in the MB6 it is a good idea to test it in the car.

The first thing to do is to check for any cell codes by bridging the 2-pin service connector (found behind the passenger side kick panel - as shown in the picture on the right), turn the ignition on (but do not start the car) then read the codes displayed by the service light in the instrument cluster.  If all is how it should be you will get codes 20 (Electrical Load Detector) and 23 (Knock Sensor).  These are not fitted to the MB6 as standard but after adding an external chip you will be able to disable these codes.

How to check if IAB's are working

Once this stage of the modding is complete and working you may want to socket the ecu ready to add a chip, so that it can be re-mapped to better suit your cars set-up... go to page 2