I installed a 94 JDM GSR motor in my 93 civic hb dx and the mil comes on for the o2 sensor heater, code 41... The mil doesn't come on right away but only about 10 seconds after the car has been running. I've rewired the o2, replaced the o2 sensor, and even replaced the ecu. I've taken it to 3 different shops and no one can find the problem. I'm open to any suggestions if anycone could please help. I bought a turbo and don't want to put it on until the light turns off