Still battling with my code 9, though I'm fairly certain I have it narrowed down to a wiring issue. Though resistance, continuity, and ground all check out, there are notable breaks in the shielding (right before it enters the connector on the sensor side where there is clearly exposed wire (since electrical taped to protect the sensor/ECU, at least), and possibly elsewhere. I'd just like to run a new pair of wires from the ECU to sensor, bypassing the 30 year old harnesses for now.

How picky is everything about the wiring, exactly? It's just a signal wire afaik--would simple copper shielded wire worked? Is something specific needed? Any particular gauge?

Also if you're reading this and happen to know, I have some other questions relating to the code 9 as well, just to make sure all of my bases are covered by this. With this being a 30 year old car information is getting harder to find and more and more conflicted.

Which of these things could cause a Code 9?

Wiring (obviously)
CYP sensor (obviously--both I have test good, with the current one on there being a new replacement just in case)
ECU (likewise have tried 2, both tested good, and the first one was working fine in previous motor. Both PG7)
Compression? (Some of the lines aren't in the best shape ever, but last time it was compression tested it was fine)
Ignition timing? (Would make sense, though I would think that would throw codes for one of the distributor sensors as well/instead?)
Mechanical timing? (Seeing as the sensor sits on the end of the exhaust cam it'd make sense it'd throw a code if it's not seeing #1 cylinder when it 'expects' to)
The distributor? (Don't know why it would throw a code for an external sensor but not for one of the distributor sensors)
Some random thing?

Thanks in electronic advance!

Added: The most obvious shielding break: