HI,
With the ignition on the + wire at the coil, is there battery voltage at this wire
(primary) the other wire - green, goes from the coil, to pin1 on the ignition ecu, and as its split from the coil the other end goes to the rev counter
and then to the injection relay under the drivers side dash purple,at pin 1.? check all for continuity, the +from the coil goes to the ignition switch.also check plug's of the ecu's make good contact, and battery terminals are tight, the green wire from the coil, in the loom it passes the front crossmember so check in this area it is not chaffed on metal, and check any brown wire to the chassis are tight, earths. have you tried another ecu (silver) s2 wiring changed slightly over time

Dave R