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Forum namePerformance/Engine
Topic subjectHow to get rid of the *No-Cat* CEL
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=72197
72197, How to get rid of the *No-Cat* CEL
Posted by 992gnt, Apr-05-04 02:14 PM
Hopefully this isn't an Evo-only fix (or a repost), and I'm not sure if there is room under the 2gnt, but here goes.

I don't have a cat on the Evo, and it's annoying having a CEL on in a brand new car. So I hatched a plan to remove the rear o2 sensor from the exhaust stream, without *actually* removing it to give the o2 sensor the feeling that it was seeing reduced emissions (gases in general). My first attempt at this involved old o2 sensors and welding. Then someone turned me on to spark plug anti-foul adapters. These can be found in the "Help" section at Autozone, etc. Get one package of the 18mm anti-foul adapters. I think I paid $3.69 for the pack of two. Take one of them and enlarge the hole (where the electrode of the spark plug would go) using a 1/2" drill bit. The hole is normally ~1/4". This will allow room for the o2 sensor to fit into the adapter. I left the second adapter alone.

I then un-screwed the stock rear o2 sensor and screwed in the un-altered adapter. Next I put in the modified adapter, and finally re-installed the o2 sensor. This will move the o2 sensor out away from the pipe about 1-1/2" and leave only a 1/4" hole for exhaust gases to get to the o2 sensor. Took longer to drill the hole than to install everything, and my CEL has been off since I did it on saturday. Of course the car won't pass a visual inspection (unless I tack some heat shields on the test pipe), but at least the light is off.

I hope this will work on a 2g, someone try it and let me know.

72201, RE: How to get rid of the *No-Cat* CEL
Posted by Dave41079, Apr-05-04 02:22 PM
It's a lot easier to just wire in a 1 mega ohm resistor in the blue wire. But I commend you on trying something new. Let us know how it works out after a few weeks.
72202, RE: How to get rid of the *No-Cat* CEL
Posted by 992gnt, Apr-05-04 02:29 PM
The resistor mod doesn't seem to work on the Evo. :scratch Even the o2 eliminator kits haven't worked with any regularity.

72214, RE: How to get rid of the *No-Cat* CEL
Posted by GhEttOrAiD, Apr-05-04 05:18 PM
well.. we do have a completely different motor

cool idea!
72215, RE: How to get rid of the *No-Cat* CEL
Posted by Ryan_Hes, Apr-05-04 05:21 PM
I installed the resister inline on the black wire to the O2 sensor last Saturday and my CEL won't go away....do I have to clear it?
72228, RE: How to get rid of the *No-Cat* CEL
Posted by soulcontroller, Apr-05-04 06:03 PM
yes ryan you have to clear it. you should be able to do so by unplugging your battery for a few minutes. that cleared mine up. i still have the EVAP CEL though. that ones never goin away.