Ok so I did the vtec swap on my 01 civic lx. I know most people say just use all your original stuff and just get the vafc controller and call it a day, but I didn't quite do that. I got the vtec wiring harness with the head and I already had an ex ecu lying around so I did the swap like that. For the most part everything works fine. Granted I had to go by a new water passage to fit the egr valve that I had to buy which wasn't very fun but again it works.

My only problem now is that the ex harness only comes with one of the o2 sensor plugs so obviously car is throwing codes because of one of the sensors not plugged in. What I want to know is what would be the best way in wiring the other sensor into the ecu. I know based on the ecu diagram i need the o2 sensor wire and heater control wire to be plugged in, but I just wanted to know if I spliced the other two wires to the existing sensor plug that has the same two color wires would that cause problems or what.

Any suggestions to help me with this would be great.

 

I would love to know a little more on this myself. I just did a swap in my 2002 lx and am having the same problem. But I still need the ecu as well. I have my factory one running the car as of righ now.

 

Ok so i'm glad a lot of people wrote back on this and helped me, but enough of being an ***. I wired the heater control wire and the main o2 sensor wire into the ecu based on the ex ecu pinout not the lx. The other two wires, I just spliced to the wires of similar color to the other sensor. Now this technically made it work, but the only issue that I did not realize until further research is that the lx exhaust and ex exhaust systems are not only different as far as piping but also as far as the o2 sensor placements. What is considered the Secondary o2 sensor and behind the cat on an ex exhaust is actually the first o2 sensor you come to on the lx exhaust.

So obviously because of that being that I have a defouler plug on the bottom sensor which was my primary and a/f sensor it was making my computer act like it was on crack because its pushing in more fuel but at the same time trying to lean it out because the sensors were tripping it out. The one that is plugged on top is the one thats suppose to be tricked as far as making it think the cat is working but instead its sitting right in front of the exhaust and telling the computer it's putting too much gas in the car. So it's been an interesting couple of weeks trying to figure that out.

But anyways I just wrote that up there incase someone else does the full entire head swap they would know what to look for.