i have a 1998 ex. i bought a full exhaust system of ebay because money is an issue. anyway i need to pass emission. its a header testpipe and full catback. so basicly its all staight thru except a muffler. thebung for the o2 after the test pipe is poined to the ground. with a spacer its like .5 inch above ground so i changed it and put it infront of the test pipe. it throws check engines like no other. i put another spacer on the first o2 to try and fix it. and nothing. so do i need to take the first spacer off and get a cat and put a 90 degree spacer on the o2 after the cat? will this work? what will???

 

https://www.hondacivicforum.com/foru...ad.php?t=73237

Do this. You essentially have the EX setup but you have a test pipe instead of a cat.

All you need to do is install a catalytic converter (beware of ebay "catalytic converters"... the no-name ones are just test pipes) and use an O2 sensor wire harness extender like in the thread I just posted you a link to so that there is an O2 sensor in the catalytic converter. You don't need a "spacer"... I have not a clue what you are talking about.

O2 sensor harness
catalytic converter - I personally recommend this one. You won't find one cheaper brand new, and your only cheaper option is to find a used 96-00 EX catalytic converter.