I have a 2000 civic si with a JDM B18C swap with OBDII sensors switched over and am running the B16 stock ecu. when i did the swap the check engine light stayed on and when i checked the code it was the O2 sensor. So i bought an OBD2 to OBD1 conversion harness and b18c ecu and the light is off but i am getting horrible gas milage, anyone know what to do.

 

get it tuned.

 

What year is your swap? I have a '99 JDM B18c-R OBD2 swap with the USDM R ECU and got the o2 sensor code but I found out my cat was clogged. But i swithced to a JDM R ECU and no code because it doesn't read the 2nd o2 sensor.

 

the motor is like a 94 i think, but the sensors were swapped over from my b16a2 to this motor