Hello Everyone,

I’ve been lurking for a long time and searching for basic information on how a MEFI ECU calculates fuel and spark. I understand the ECU uses tables and various inputs, but I cannot find any information on how mathematically these calculations are interpolated. Ideally, what I’d like to do is make some sort of spreadsheet where you could input a set RPM, load, MAT, throttle, etc. to have a good idea of what your final fuel and spark delivery would be. Also, I’d like to estimate fuel mass and pulsewidth. I just don’t know the logic inside the MEFI ECU. It doesn’t have to be exact, but just an overall estimate.

Would anyone have something like this or any resources on this topic? Would anyone have information on the parameter definitions within MEFI? I’d appreciate the help.

Thanks,
Paul

Mefi is a speed density system that uses a basic lookup table for rpm and map to get pulse width. Then there are many modifier tables for accel/decel, temp, mat, boost, etc., Spark is the same way.

Bob answered it best,the program uses preset look-up tables then modifies the numbers from pre-set parameters in modifier tables ,Smitty