ECU question

When I got my engine swapped, the guy never replaced the ecu. I had a d15b7 replaced with the same one, but only japanese. The japanese one was a carb converted into a fuel injector. Would I need a japanese ecu even though it's the same engine? I have SERIOUS ideling problems!! My "check engine" light has been on ever since the swap. I really need to know how to fix the ideling problem. Anyone have any ideas what it could be?

Thanx for any info