There is actually a guy who has product out for the 4A-GE. It is a daughterboard on the stock ECU, and it allows remapping and a real-time readout of all sensors as well as some internal processor parameters. See here, here, etc. The root directory has a raw listing, but no index or linking pages.

I am totally uninterested in doing the extensive development work, mapping out of sensors, and trial-and-error tuning to get a working baseline with a Megasquirt. Then there is the issue of connectors, etc. Considering that I couldn't even obtain the hardware for a Megasquirt solution for less than I intend to retail the ECU mods for, it just doens't make any sense to me to pursue, especially as I don't really have the time or energy for creating a solution from scratch. 98% of the work has been done for me by NipponDenso; I get the reliability of the stock sensor and harness, and just get access to sensor data and map tables.

The ECUs in question are from a Mazda and a Honda motorcycle, and I believe they are both 8051-based. I have been able to read out map data from inside the Honda MPU, as well as from an outboard chip; the MPU was addressed as if it were an 8048-series chip, whch I suspect is why the runtime was not obtained (this was done by someone else, and I was just given the hex dumps). Neither box controls spark, although the Honda box has some very sophisticated maps (largely due to the fact that it is turbocharged from the factory).

If I can verify the pinout and get ROM dumps from these chips, I have a variety of options, and I'll have to explore what makes the most sense. Atmel has an 8051-compatible series with built-in CAN bus as well as USB, which might be a good way to go (since the forthcoming OBD-IV standard mandates the use of CAN bus as the de facto interface, and will likely come with a pass-thru standard in place; this would mean all diagnostic and remapping software for cars and probably for motorcycles as well would operate via CAN bus, so having a unit which can be accessed with the same software would be a boon, and would be transferable to other 8051-based ND ECUs.


As an aside, if there are those on the forums here who have the knowledge to help me, but would not be interested in spending time on this without compensation, I would also be willing to hire someone to assist me on the basic develpoment work, as lohng as it didn't bankrupt me. :D