I'm throwing a code 67, its a 98 civic with a D16y7 i have an aftermarket headre with the firt o2 sensor in the header itself and the second one in the downpipe. I have a 2.25in cat after the downpipe. Do you guys think that it is a bad secondary o2 sensor or a bad catalytic converter? Whatever it is will i be able to pass my emissions test which i have to take in the next week or so. Anything would be helpful. Thanks

Sydney

 

oh yeah i dropped the secondary o2 sensor when i was doing my header install. You think that could be it???

 

Could be the O2 but also, KIM (Keep in mind) the 2nd O2 sensor is supposed to be behind the cat.

 

Is it hurting performance? Do you think that I will still pass emissions

 

Your problem is your 2nd O2 sensor is in the down pipe- it needs to be after the converter.

 

so i should be able to pass emissions right? Even though it is in the down pipe. I'm going to be doing a swap soon and I plan on going with one o2 sensor so I don't want to worry about welding a new bung for the second o2 sensor

 

oh yeah it will pass emissions and yes the o2 should be in the cat to sense the gases after the cat and see how clean they are.

 

But insnt code 67 "Catalyst system Efficiency Below Threshold malfunctioning or defective catalyst system" i got this at c speedracing.
anyway, if the 02 sensor is malfuntion, wouldnt it thrown some other code like 61-63-65?

 

yep- catalyst efficiency- but the second O2 monitors the cat- how do you expect it to monitor the cat if it is before the cat- move the O2 after the cat. No one said the O2 was malfunctioning