For those of you interested in communicating with your 2nd Gen ECUs the following may be of interest.

http://i153.photobucket.com/albums/s222/ac1176/Bloody%20Cars/20150530_103942_zpswqevherh.jpg
http://i153.photobucket.com/albums/s222/ac1176/Bloody%20Cars/20150530_104338_zpsqmfy9r1v.jpg

You will need a computer/laptop with a 9-pin serial port and a straight through 9-pin serial cable. It may be possible to use a USB to Serial converter if your computer doesn't have a serial port, but I haven't had the opportunity yet to try it out to confirm it works.

Software-wise I have only tried this with a terminal program. Br@y's Terminal (https://sites.google.com/site/terminalbpp/) or Realterm (http://realterm.sourceforge.net/) are both good for PC. I'm sure there are other equivalents for Mac or Linux. I haven't tried this on some of the abandonware freebie programs that were developed for probing Lancer Evo ECUs (eg OBDGuage (http://www.qcontinuum.org/obdgauge/index.htm), Mitsulogger (https://www.aktivematrix.com/blog/aktivematrix-useful-info) etc) but it may work with them too.

If using a terminal program the required data format is:

Baud rate = 1920
Data = 8 bits
Stop bit = 1
Parity = None


Schematic. Note that I have redrawn the original shown here (http://mmcdlogger.sourceforge.net/) to include an onboard power supply derived from the unused serial port pins:

http://i153.photobucket.com/albums/s222/ac1176/Bloody%20Cars/Mits%20Interface%20Schem_zpsurnw9aey.png

Layout for veroboard. If you're going to build this note the orientation of the components (electrolytic capacitors C1/C2/C3/C4/C5/C7, diodes D1-D3, LED D4, IC1, transistor Q1-Q3). Orientation of the resistors and capacitor C6 is not important. There are a number of traces that need to be joined by the use of short pieces of wire indicated by the solid black vertical lines. Note also the requirement to cut the traces on the board in key areas (denoted by the yellow box with a dot in the middle), particularly underneath IC1. It may be wise to also buy a 16 pin IC socket for the MAX232 if you want to check the board before fitting the chip. The red LED is used to set the power supply voltage to 5V and different LEDs can change this voltage - buy a few to swap around until you find one that sets the power supply at roughly 5V. All the parts should be obtainable from Jaycar for less than $30 total. The pictures at the top of this post are from an earlier prototype of the converter that doesn't quite match the layout below, but does give an indication of how compact the interface can be:

http://i153.photobucket.com/albums/s222/ac1176/Bloody%20Cars/Mits%20Interface%20Layout_zpsgnhhk10h.png

Note: that this uses a red LED as part of the voltage regulator.
Other colours have a higher forward voltage drop and will push the ouput voltage above 5 volts.

Only just glanced at his circuit from ac1176, but probably doesn't matter if vcc is a bit higher.

ac, thank you very much for that, definitely a todo'er.