ive been doing alot of reading of honda engine swaping, and everywhere you look it always says to use your original engine harness, and modify it to work for the motor you are installing, and not start with your donor motor harness. this is probably way to simple to work, but the idea came to me, and it just seemed to simple. could you use the entire engine harness from the donor motor you are swapping in, so all the connectors plug perfectly into the motor plugs already, and get the ecu for the donor motor also, so the motor wiring will plug directly into the new ecu. then switch the connectors on the underdash harness to plug into the new ecu... This most likely is way to simple to work, so i am assuming that it wont work, but it was worth asking.