I just finished a CX to HX swap. I have been riding around all day without the secondary o2 connected and I haven't had the CEL come on. Is this a problem. Do HX's shudder when they do into lean-burn lie VX's. A few years ago I swapped a VX engine into an HF and I got a definite shudder.

 

What ECU and wire harness?

 

HX engine harness, lx main harness, lx body harness, ex climate harness, unknown dash harness, A22 ecu from 96 hx

 

I think you mean P2N ECU.

Does the CEL work?

Have you tried jumping the service connector or pulling codes with a code reader?