Plug In Board Process
have wiring diagrams in random loose format: pictures, scans, PDF, text.
have ECU connector pin-out in google spreadsheet form, with explicit function of each pin, often with analysis of multiple vehicles with similar pin-out. Good example
Breakout board for that connector to reduce risks, also a product by itself!
Pin-out data entry into KiCAD
Proteus or else adapter for specific vehicle, based on steps 2, 3 and 4. Because cheaper fabrication and less labor intense.
Full plug in board like Hellen if demand exists. See https://github.com/rusefi/rusefi/wiki/Standalone-on-Demand
We are getting good at these Hellen boards but a board is not done until tested on a real vehicle. A master tech skill set is needed to turn a Hellen into a proven board!
