Amp (type mounted on dizzy) has (hopefully) two blades, one in line with the amp body and the other across (also nearest the corner).
Inline should have a white wire which is ignition switched +12v also supplying the coil +ve.
Crosswise should be white/black going to coil negative.
The coil negative should also have a resistor coming off of it with the other end connecting to the ECU pin 1 with white/black wire.
Steve
Edit.......I'm not too far away from you and have most of the bits you may want to borrow to swap out with yours to find issues. Flapper, dizzy, ECU, coil. + a whole dead 3.5 engine recently removed from my Dakar.