After installing my K&N CAI 3 days ago, my check engine light came on. Code P0420 (Catalyst efficiency low-bank 1). I was reading all the postings related to that code here, but nothing appears that that code is related to a CAI replacement. Does anyoneknow if the CAI could mess up the CAT converter? or it is pure coincidence? thanks!!

 

It's possible that it's related but doubtfull... I've never seen that happen on a honda.... I did a little searching however and have noticed that a few people got that same issue when they were running bosch plugs (which imports don't like) they cleared the code and switched to NGK's and the problem went away....

Are you running bosch plugs? (honda's hate them too BTW... they like to fry ignitors)

 

No, I'mrunning Denso Standards. Should I replace them with NGK (which ones if so?). What type of test you recommend me to do in order to make sure it isa badcat before replace it? Thx!!

 

bank 1 is the primary sensor I believe which is located on your exhaust manifold and not cat related..... I don't know much about the denso's though.... I'm going to let someone else comment on this one but I believe that is your exhaust manifold sensor in the engine bay.... they are more prone to "failure" if you do mostly city driving...

I think this is in your signature block but I didn't notice if it was.... what year/make/model and mileage is the vehicle?

 

It is a 1999 Honda Accord EX V6 127,000 miles and most of them are highway miles. I drive around 70 miles round trip from work.

When you talk about "primary sensor bank 1" you mean O2 sensor before catalytic converter?

 

Yes, I mean the O2 sensor that is on your Exhaust Manifold in the engine bay

 

sir_nasty,

What do think about this? I found it in another forum...

Originally Posted by notoriousB [/align]"yup, we did this for a grand total of $3.99+tax i believe!

get this "help" part at your local parts store: 18mm defouler - comes in a pack of 2

here's the package and the two defoulers screwed together


i drilled out the bottom of one with a 1/2 inch drill bit - go slow, use lots of oil, it's thick

i don't have any pictures of the one drilled out alone, but here's two pics of the final product, one from the bottom one from the top. in the second pic you can see how it was drilled. the drilling is done to be able to fit the o2 sensor thru the 1st defouler.





final product all installed, and skabone confirms "it works!!"



had to persuade the heatshield slightly to clear the new longer o2 sensor but that's no problem.[/align][/align]it pretty much tricks the secondary 02 sensor and tells the car that the emissions are running fine. you'll only need to run the defouler for the 02 sensor that is in the cat. I've had the defouler on my car since May and I haven't had a problem. in fact I'm getting better mileage now. I was getting 330-360 miles on a tank of gas, now I'm getting 390-410 miles on a tank of gas."[/align][/align][/align]By the other hand, I'm in Orlando Florida, no emission test required. If Iwant tohook up my car with headers and a catback can I discard the Cat converter??[/align]