I recently swapped my B16A from my previous 1990 Integra RS into my new 1993 Integra LS, im now receiving this code, but it takes awhile, the car will fully warm before this code is thrown. I had to lengthen the wires to run from the rear to the front in the header, but if my wiring was incorrect wouldnt the code be constantly thrown? Should I just replace the O2 sensor? I know my "green" and "white" wires are correct, but the other two "black" wires could be mixed up?

I have also gotten the code 20, but it to doesnt pop up until the other codes have been thrown? What exactly is this code?