How to code out O2 sensors/cats?

Rayyy · Jun 3, 2022

Well, converting my truck to off-road only… and wondering how to code out the O2 sensors if I remove my cats?

And if I do code them out, will I still be able to pass smog? (No sniffer)

Scottydoggs · Jun 3, 2022

you live in ****** CA. they can now tell if codes have been deleted.

if you remove the cats your not passing either.

if truly off road why you need inspection? then you can delete codes and delete the cats with no issue at all.

Rayyy · Jun 4, 2022

Fair points. I’d like to be able to pass smog in case I ever want to register it again for street use.

I’ll try the defouler method or silicone method, and perhaps one of those will work.

Alex_M · Jun 4, 2022

Get some of the 90 degree defowlers, they'll work. You need HP tuners to tune the code out which is $400.

You can also just get a set of high flow converters for about $65 or $70 on ebay. And you won't have to worry about it. Unless your converters are clogged you will notice zero difference in power or mileage, but your factory converters should be worth $300 or so in scrap. Give or take. Depends on the numbers.

Scottydoggs · Jun 4, 2022

defouler's do work. but some how im sure they are going to look to see a cat or two. unless you cut yours open on the top where it cant be seen, gut em. and weld it back shut. you cant even pass with a high flow cat over there. needs to be a oem style cat.

iamdub · Jun 4, 2022

Rayyy said:
Well, converting my truck to off-road only… and wondering how to code out the O2 sensors if I remove my cats?

And if I do code them out, will I still be able to pass smog? (No sniffer)

OEM cat is a "high-flow". The aftermarket ones advertised as a "performance/high flow" cat are the same design, just shorter and with far less catalyst. A tuner can disable the codes, remove the speed limiter and other items without any actual tuning (tweaks to the fuel and ignition maps, trans tables, etc.). I had a local one do mine for $150.

A member here recently did the non-fouler trick and has reported success.

If you do gut your cats, save some of the catalyst in case you (or someone else?) needs to put some in a non-fouler.

Mudsport96 · Jun 5, 2022

Are your cats plugged? You MAY see a 3 hp gain by removing your cats. If they are plugged you would see more, but today's cats flow more than the stock engine needs them too.

How to code out O2 sensors/cats?

Rayyy

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Rayyy

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Alex_M

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