Ok so I have a '96 Civic with a B18C swap and an OBD1 ECU/OBD2 to OBD1 conversion harness and Hondata S100. The car has a DC Race header with no cat. Since the swap the car has had the CEL light on and a Code 41. Bought a brand new Bosch universal O2 and wired it in, reset the ECU and still have the code. Removed the O2, checked the wiring, plugged it back in, ran the car a bit and still have the same code. As far as everything else, the car runs good, still a bit rich. What could it be?

 

I'm not familiar with the Bosch universal O2 sensor, but I'd go with the OEM stuff just to make sure. Your OEM unit was a 4 wire correct? Is the Bosch a 4 wire? Is the S100 set for closed loop or open loop?

 

Every thing is 4 wire. The Bosch sensor I bought is 4 wire. 1 Gray, 1 Black, 2 White. The OEM plug off of the original sensor has 1 Green, 1 White, 2 Black. According to the instructions that come with the Bosch sensor. I wired it OE Green to Bosch Grey, OE White to Bosch Black, and the 2 OE Black (Heater) wires to the 2 Bosch White wires. The S100 came with the car installed already when I bought it, so I'm not entirely sure how it was set up. The original owner told me that the car didn't need a front O2, but I'm not sure on that either. I've always been told in order for most cars to run reliably on the street, they at least need the front O2.

 

I had a 95 hatch with a 2001 b18c1 in it and didn't need any O2 sensors. I would have someone check the 'closed' or 'open' loop of your S100. You are probably better off to speak to someone (Hondata dealer) regarding tuning and 'closed' or 'open' loop rather than buying another O2 sensor.