There are two crank angle sensors in the dizzy. Both are photocell/led pairs with a slotted wheel on the dizzy shaft, one set of slots with 6 and one with 36 (may be off one on both) that provide a coarse and fine measurement of crank angle to the ecu. If you have no signal, either the led or the photocell has died, or, most likely, the wiring connections have failed. Test the circuit from the new plug to the ecu with a battery for signal source. I use those straight pins with a plastic ball on the end to pierce wires to detect voltage. Check the ecu connector for a loose pin. They lose their grip on the connector housing and get pushed back when it's plugged in. Mitsu has a habit of using wires that get brittle insulation after long exposure to heat, and that can crack and over time the wire at the crack breaks from fatigue from flexing. Check all the wires inside the dizzy...

Peel the tape on that harness and look for a red wire, only solid red wire in that bundle, and see if the pin was pushed back out of the connector. If so, pry up the little tang on the pin so it will catch in the connector again. If no wire, you got me - maybe the 'lectron gremlins ate it...

Like you, I guess, I'm looking at the 91fsm. Should be the same as the 90, different from the 89, but the 89 manual has a much more complete description of how to disassemble the connectors.

You may be on the right track there. Spark failure is commonly the first sign of ecu cap leakage damage.

I'm a little confused. You say the 22 position in the connector is blank, but that the wire was good? I may have some understanding. Position 9 in the connector is blank, and would be above 21. Most connector nubering on Mitsu's is R-L, in this case 1-12 on the top (connector catch up) row, and 13-24 in the bottom row.

You may be on the right track there. Spark failure is commonly the first sign of ecu cap leakage damage.