socalrocks

Tried the search engine, but couldn't find an exact answer. Anyway, I've got a 1998 civic hatch, d16y7, that I bought with a crack (pretty big) on the exhaust manifold. I put a new (actually used) catalytic converter / exhaust manifold (no cracks) in the other day, after clearing the code, thinking it would stay that way. After 40 miles of driving, the CEL is back on. It is still pulling a P0420 code, as it had been before -- Catalyst system efficiency below threshold (bank 1)

Could this mean one of the o2 sensors has gone bad, and needs replacement, or would that bring up another code? Also, what does "bank 1" refer to specifically? Any suggestions/knowledge?

Thanks!

deving916

iTrader: (2)

I had the same code on my ej8 coupe.
You could also have an exhaust leak somewhere.
I didn't want to spend the $ to replace the cat yet, so I tried the "spark plug non-fouler" trick and it worked like a charm.
200 Miles later and no light yet.


https://honda-tech.com/forums/acura-integra-type-r-8/spark-plug-non-fouler-1841240/

socalrocks

Cool, thanks for that tip. That might come in handy soon.

Although, I am really still looking to find the root of the problem ideally, does anybody have any ideas?

Former User

Either the replacement cat is bad or there's an exhaust leak.

motegicivic

Did you reset the ecu after the work was done?