ClassyG

I have 1997 Honda civic EX that had a LS B18 motor swap from a 1999 Acura integra. The check engine light came on and gave the code P0420(Bank 1 below threshold). I had the cat converter replace and the code came back on. I aslo tried a new 02 sensor and it came back again. My question is does it matter which 02 sensor I get, or will the same one for a civic work on a integra? Not sure if they just giving diff readings.

HondaPartsHero

What kind of cat did you use?

ClassyG

High flow universal cat converter that you have to weld on.

HondaPartsHero

That's more than likely your issue. You'll need to get a cat close to oem as possible. You could try a defouler and see if it can trick it.

ClassyG

Ok I'll try it, but will it affect the air/fuel ratio by getting a different reading at all?

ClassyG

I tried the spark plug Non-fouler and the CEL has not come back on since, thanks.