S12 Connectors (located under the S12 MAF/Airbox combo)
There are some specifics you'll need to know:
1. The S13 BLACK/RED wire, its a thicker wire, needs to be connected to an S12 wire NOT in the connectors pictured. You'll need to pick this wire up at where one of the old S12 coils used to be, there is two possible connections (two coils) so which is up to you. This Black/White S12 wire will be large gauge like the S13 Black/RED wire. Since you had a Turbo model, you will have standard-type connections still on these Black/White wires, so either find a connector to mate to it (from a jyard car say) or strip&splice, its up to you. If you have any questions as to which connector or how this will work, just ask. In the other MK1 KA swap guides this is detailed, but CA20s use old style canister coils with simple eyelet type terminals which are easy to find and connect to. lmk if you have questions.
2. The S13
BROWN(sensors) and BLACK/YELLOW (air regulator) are going to both go to the S12 BLACK/RED wire, as there will be sufficent current available thru this wire (its a 10amp fuse) to power all the S13 devices that will be connected to it.
3. I made a change to the tach wiring. In the past, and in all the other swap guides out right now, I list a yellow/red wire as the tach output, which it is... on an s13. On an S13 tho its a much lower output for the computerized S13 dash, but S12s need the more solid 12v signal directly off of the coil. So what you need to do, according to the research I've done, would be to tap AT the S13 coil the Light Green/Black wire and connect that to the S12's LightGreen wire. I have not verified this, so I'm not 100% sure on this, and there really should be a diode/resistor in the line to prevent feedback, so if you want to leave it disconnected for now that would be allright. There is a diode/resistor IN the S12 harness already, so it might be possible to connect directly to this, but I need to look into this further. If you look near one of the coil locations, you'll see a little gray box wrapped into the loom, thats the diode, I think the s13 coil jumper for the tach should connect to it, but get it running first, and it can be figured out later.
4. The coolant temp sensor wire is also not confirmed, but it would be cool if you could test it out. The S13 BLUE/BLACK wire should be near the ECU connector where there are wires cut real short.
5. MK1 Turbos did not use neutral safety switches, I've not had any issue leaving them disconnected on KAs so there should be no problem there.
A good way to cap off the wires you won't be needing... seeing as yours are missing the connections. you might notice this connector is the engine harness side of the Turbo chassis connectors from above, I salvaged them from a burned harness, otherwise I prefer not to cut. Thats liquid electrical tape (Home Depot) dabbled in two layers over the bare ends,
In regards to the fuel pump, I will simply refer you to what I wrote for the MK1 CA20 swap guide, as that is the same. http://club-s12.org/v3/index.php?topic=21003
third post. Obviously the connector will be a bit different but use the pics above and you'll be fine, the function is the same.
here's the S13 harness connectors....