[Richard L]

The red wire of yellow connector should be connected to a 12V source when the injector (+) becomes active. On most car, the ignition switch + at the "pre-crank" position fits this criteria.

The safest and most reliable way of wiring the green and red wire of the yellow connector is at the fuel injector itself, if you are not sure. Never wire the red wire at the "Acc" position of the key switch.

What car do you car, I may have the ECU pin out diagram for it.

If the purple wire is not used just isolate it with some electrical tape. The black and white wire must only be terminated together at the ground junction.