2006 Scag SST 61 turf tiger Kawasaki 29 DFI wiring harness

I bought this mower as a project as it had electrical issues and the previous owner didn’t want to fix. Here’s what I know.
The mower will turn over
It has spark on both cylinders
It’s has 150 lbs compression on both cylinders
It will fire after a little carb cleaners is squirted in the cylinders
The fuel pump is good and has good fuel pressure up to the top of the engine
The previous owner started bypassing all kinds of stuff on the harness so I am starting new with a new harness and computer(the one under the key switch panel)

I have the new harness installed but there is a red with green stripe wire that is in a single plug that I’m not sure where it goes. I don’t see any logical connection and the wiring diagram just says it goes from the fuel pump relay to the main relay to a non descriptive “engine” connection.

Also I don’t see anything in the wiring diagram that shows the injectors and the other “computer” looking block that is near the battery. Any help here would be great too.

I’m guessing my main issue is going to be getting the injectors to fire and deliver fuel to the cylinders.

Any help would be greatly appreciated! Even a few pics of this other harness that connects to the injectors would be awesome.
Thank you in advance for your help.