Although i dont consider myself even remotely intellectual with electronic my yrs fiddling with cars leads me to a conclusion.

Are all required earthing points attached

You'd be surprised what missing just 1 earth can do. Especially the engine earth to the chassis.

Injectors have power but are they being earthed but the ecu. Node light is beneficial for that.

The fact you have zero spark and injector pulse id start with an earth. Looking as dizzy signal etc wont find you shit i wouldn't think.

If ecu is reading a false signal from dizzy etc would it still try to fire injectors and ignition, i would think so. Unless it goes into a retard mode, and does nothing at all.