86 na wiring to 84 turbo wiring

So I have finally got my engine ready to drop into the car. I am working on swapping the engine wiring harness over and I have run into some trouble. My main problem is under the battery shelf on the 84 there is a small box tagged "electronic control system." My 86 doesn't have this box to plug into. I want to know if that box is necessary or if I can just forget about. Then there is a connection that runs underneath the battery that connects to the engine harness. The 84 has a 4 wired connection(red/yellow, brown, black and white). The 86 has a 2 wire connection(red/yellow and brown). I tried locating this in the wiring diagrams in the haynes manual. I would like to know if these are the same. I will run by the shop today and take a few pictures for a visual. Thanks for the help.