Cat sensor question, check engine light, etc
 

Hello, I'm new to the forum, with a 2000 Civic EX 5-spd. Here's the story:

I got a straight-pipe to replace the cat a few months ago, after I installed it the check engine light came on (since I cut the wires to the cat sensor). I was fine with it until now because I have to go get emissions done (GA) in order to renew the tag. So Here's my question: Will the engine light go off if I just re-wire the sensor back on (and leave it hanging) while still keeping the straight-pipe on? If not, when I put the cat back on with the sensor installed will the check engine light stay on or do I have to reset it or something? Third, there are 4 wires for the sensor, a white a green and 2 blacks (no distinguishing marks to tell the difference). How do I know which black wires go to each other?

Here's what I have already done: Tried wiring the sensor back on in both black wire configurations and started the car, but the engine light never went off. Could this have worked if there is some sort of way to reset the ECU?

Thanks so much in advance for your replies!! I am anxiously awaiting your responses O' guru's of civics.

RE: Cat sensor question, check engine light, etc
 

You have to reset the light for it to go off. Pull the batt cable or the ECU fuse


You will need to put the stock cat back in to pass emisions.

The O2 will need to be plugged in




BTW, you are making less power as long as your CEL is on cause the car goes into a "safe made" closed loop mapping. You will gain power from the old stock cat or get a O2 simulator to keep the O2 sensor happy

RE: Cat sensor question, check engine light, etc
 

u need to find an o2 simulator---you have a heated o2 sensor --spliceing wires into each other might do more damage----or go back to a stock cat

RE: Cat sensor question, check engine light, etc
 

Thanks for all the help guys! Here's how it ended up in case anyone has to do what I did:

I got the O2 sensor simulator off ebay, the instructions were wrong but the seller emailed me back and gave me the correct ones. You are supposed to leave the 2 black wires intact and splice the simulator in with the green and white wires. The first time I tried it the CEL didn't come on so I went to the emissions place and it failed. Not because the o2 sensor but because there was no readings from the ecu. Evidently you have to put some miles on the car before it will pass. So 15 miles down the road the CEL came back on. D@mnit! I swapped the 2 black wires (becasue there are no distinguishing marks on them) and drove for about 20 miles with turning the car off and on again and the CEL never came on. So I went to get the emissions done and IT PASSED!! Woo-hoo!

Thanks again everyone!! Oh yeah, just checking this site gave me the itch to get some headers and a cat-back now too. Headers are on the way already (4-2-1). Never ending money pit....

RE: Cat sensor question, check engine light, etc
 

do you have to get one for a civic? or just a unerversal one?

RE: Cat sensor question, check engine light, etc
 

The title on the ebay auction said "civic" but in the body it said it would work for ford's, chevy's, honda's etc. So I assume I got the one that was universal.