[Christ]

Normally, when swapping in a new engine, you're better off to use your existing harness and add/modify where necessary.

For a good example of why, look into swapping a 4th gen SI engine into a DX. The wiring harnesses are completely incompatible, unless you plan on putting the entire chassis harness into the car as well. You'd spend less time and effort (in that case) just adding in the 4 wires necessary and moving a few around to support the new engine.

In your case, there would be more moving/addition, but OBD2 subharnesses can be bought cheaply, and they plug right into your existing harness to move the wires to the points they need to be for the OBD2 ECU. After that, it's a matter of adding in the wires you need for the sensors into the existing plugs from your chassis. I have a feeling if you'd gone this route, you'd be done with wiring already.