hey evreyone. i hope this is the right section to post in, if not im sorry. So I installed my o2 housing not too long ago and got a check engine light. turns out i somehow broke my primary o2 sensor so i had it replaced. I also added non fouler plugs to this sensor incase that was the reason why it broke. the light was cleared and stayed off for about 50 some odd miles. It returned and when i had the light checked again, it threw a p0420 code(catalyst efficiancy below threshold bank 1) I checked this forum and the socalevo forum and everyone seems to agree that the non fouler plugs are the right fix for this code, however, i already had one on my secondary o2 sensor when i threw the code. I checked the wiring to the sensor and every thing is ok, i checked for exhaust leaks are there are none. If anyone can help me with this issue it would be a great help and take a load off my chest.

my mods incase it helps:
apex intake
megan o2 housing with o2 fix
megan downpipe
works hfc
hks exhaust with o2 fix
greddy ts bov(recirc)

Thanks for any help anyone can give me.

 

did you have to extend your o2 sensor for the o2 housing? i remember i got a CEL after installing my o2 housing and high flow cat. i installed 2 non foulers in the high flow cat and reset my ecu. the CEL came back on after about 50 miles. i had to extend the wires for the o2 sensor on the o2 housing and it turns out one of the wires came loose. i fixed it and i haven't had a CEL ever since.

 

well i dont think its the o2 sensor on the o2 housing since that one is new. and the code my ecu is throwing now is for the second o2 sensor. but maybe i should just recheck the wiring for that one. should i just rip open covering that goes around the wiring? And by "extend you o2 sensor for the o2 housing" do you mean with non foulers? if so, yes i did.. but someone just told me that i shouldnt because i need that to read fuel. so i guess ill be taking those non foulers off.

 

you need to remove the non fouler from your primary o2 sensor. you only need one for the secondary o2 senseor.

 

+1^ front O2 sensor can't be out of the exhaust stream.

 

ok, ill take that off as soon as possible.. thanks for the heads up... its funny cuz i call megan directly and they said i needed to put one on.

 

my guess is recheck the wiring or buy a standalone and you wont have to worry about check engine codes.

 

Exactly. First one needs to read the exhaust so second one can read a difference to make sure the cat is working... no cat, second O2 need to be moved out if direct stream more to fake a difference. more or less.

 

does bank 1 mean anything? the reader said catalyst efficiency below threshold bank 1. This is wat came up when i looked it up:

"Basically this means that the oxygen sensor downstream (after) the catalytic converter on bank 1 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system."

 

some cars have more than one bank (not the evo) like dual exhaust, then it will have codes for both so when the error goes, techs will know what bank or side of the exhaust if there is a dual setup.

 

ah, i see... so p0420 is deffinately the secondary o2 sensor tho. i took off the foulers from the o2 housing and added one more to the secondary... hopefully that will fix everything. havnt driven my car yet. kinda scared since i already had to buy 1 o2 sensor.

THANKS FOR ALL THE HELP GUYS!