I used to get that "O2 bank2" CEL, I'm telling you put in a high-flo cat and it will go away, permenantly.

 

Umm... let's see. What's the difference between extending the wires and using the extension that DC supplies? Besides that fact, I used some 50 year old scrap speaker wire and twisted the connections together when I mocked mine up and never got a CEL.

You people? You mean black people?

 

If you have access to a scan tool that can make O2 sensor graphs, that might help. THe 2nd O2 sensor should make a straight line (or close to it). If the 1st O2 sensor and 2nd O2 sensor make the same graph, then there is something wrong with the cat (it isn't doing its job). If the graph is real funky like, then maybe the sensor is bad. The 2nd O2 sensor should either read like a straight line or the same as the 1st O2 sensor (if the sensor is fine).

 

PLEASE READ

Read these threads (there is a link in that thread to another one) it will help you understand how to solve this problem.

 

Thanks for the link Chimera.

Had it checked out today and it appears that its actually the o2 sensor in the CAT that is not reading. The voltage didn't move at all when reving the engine ( stuck at 1.25v) so I'm assuming it might of been to ruffed up when changing out the header and exhaust.
Any cheap places to get a o2 sensor for the CAT in a 98 civic ex? Preferably Denso brand. I was quoted $180 for a new sensor at a local shop. It appears to be a different part # then the o2 sensor in the header. thx again for the help.

 

ONe last question about DC sport header's. Is it required to reuse the stock header gasket (links to CAT), or is it supposed to bolt on without a gasket?

Sorry of the lame question but i just want to know if DC also supplied a gasket specific to this header or if the factory gasket was to be reused or if the design did not require a gasket.

And also if anyone has installed a Apexi World Sport exhaust on their civic, did that also come with gaskets? I got all my stuff used, as-is, so since I'm already missing the wire extention for the o2 sensor relocation on the header I want to make sure I'm not missing anything else. It already installed without gaskets and i Had trouble lining up the pipes since i was not given the stock bolts. Is fairly well lined up but i still have a exhaust leak where the muffler bolts on to the rest of the piping.

Thx again for the help.