Ok all, i have a 98 civic dx, with the ex(d16y8) vtec swap. And the problem i ran into was that the dx cabin wiring harness is not wired for the downstream o2. If you used the ex engine harness this is how you need to wire your o2 sensor directly to your ecu. This is for an obd2a(p2p) ecu.

Sensor side wires:
Black(signal)-d14
Grey(sensor ground)-d13
White(heater)-a5
White(heater)-a28 MAKE SURE ITS A SPLICE NOT A CUT FOR THIS PIN!!

http://technet.ff-squad.com/wiring.obd2a.htm

This is the link for the pin-out to use.

Also the o2 sensor wiring will run through a rubber grommet in the floor behind the cup holders in front of the shifter. The easiest way to get to this will be remove the center console, then remove the plastic that goes around the shift boot and then to remove the cupholders by the four screws looking at you. There will be a small "box" that needs to be removed in order to get to the grommet. There will be one screw on each side of the "box" and just use a flathead screwdriver to seperate the box. Once you get your wiring connected and confirm that it works, put the wiring under the passenger side floor carpet. I HOPE THIS WORKS FOR EVERYONE!!!!!

 

Sorry to revive old thread. But besides the a28 do you splice the others? I’m about to wire an o2 to the same ecu