Plug In Board Process

Step 1 Research

have wiring diagrams in random loose format: pictures, scans, PDF, text.

Step 2 Data Entry

have ECU connector pinout in google spreadsheet form, with explicit function of each pin, often with analysis of multiple vehicles with similar pinout. Good example

Step 3 breakout

Break board for that connector to reduce risks, also a product by itself!

Step 4 Start of KiCAD

Pinout data entry into KiCAD

Step 5 Adapter

Proteus or else adapter for specific vehicle, based on steps 2, 3 and 4. Because cheaper fabrication and less labor intense.

Step 6 Plug In Hellen

Full plug in board like Hellen if demand exists. See https://github.com/rusefi/rusefi/wiki/Standalone-on-Demand

Step 7 Hellen real vehicle tests

We are getting good at these Hellen boards but a board is not done until tested on a real vehicle. A master tech skillset is needed to turn a Hellen into a proven board!