If it is of any help, here's a briefing of my Megasquirt build story:
https://www.bimmerforums.com/forum/show ... my-E32-M30
(note: all the links to the pictures work, even if sometimes they don't get loaded in the forum page. You just need to right click on the picture symbol --> open image in new tab).
Although my application was for a Motronic 1.3 wire harness, you can easily adapt it for a Motronic 1.0.
I would like to stress on what Nosis pointed out above: building the ECU it's rather easy. It's the tuning where the pain waits. Do not underestimate it.
Quite odd, tuning the high load it's rather easy. You can get good results, fast - as long as you start on the safe side, and improve in small, controlled steps. Idle and warm up tuning, they are more challenging, but doable.
I found most difficult to and/or I still have to work on:
- determine the correct injector dead time (note: the dead time changes with battery voltage, but also with the temperature of the injectors). Actually, I found this parameter to be of major importance. Start with a bad dead time, and it will induce headache all over;
- smoothing out transitions and low trottle cruising;
- reach the right MAT/CLT Correction and MAT Density Table;
- eliminate the influence of large ambient temperature changes on the quality of the tune.
Unless you have plenty of time to invest in this, you will never get nowhere near the superb tuning of a stock ECU.
But, at the same time, if you heavily modify an engine, then Megasquirt offer a good solution to reasonable tuning.