Can I leave my old wiring from my ecm in the engine bay. Like right where it was just disconnected. Im installing a Megasquirt and i want to make sure I do it right before i clear everything out. I also want to make sure i pul the right wires out.

Next thing. What is all controlled by our computers? I have an 88 tpi. I dont have a/c and my transmission is not electronically hooked up.