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i bought a set of magnaflow high flow cats and now i just need to know if i install them will codes pop up and if so should i buy some 02 sims or will i be ok. thanks, albert.
Yes, Codes P0420 & P0430 will soon trigger your CEL in the DTC...so, Your best bet is to have your 2 rear (Bank 1 & 2) 02 sensors turned OFF...by a Tuner. "02 sims" will work initially, but are a "band aid", and most eventually fail...
ok you take your sensors off it wont pass the smog test unless you beat the hell out of your car right before you get it inspected to get it as hot as possible (reduces emissions), also you cant have any codes popping up or you fail, happened to my dad on his 98 vert and 01 Z they failed him on both of them. Anyway though if you get a handheld tuner i know that you can disable the O2 sensors, You should buy a handheld tuner cause they are always good to have about 300 for one, and then when you get the time or money run over and have your car dynotuned but disabling the O2 sensors with a handheld will get rid of the code.
i think if you replace your cats with high flow cats it will not pass smog atleast the inspection part.
does anyone know how to turn off the o2 sensors with ls1 edit, thanks.
I get codes from the downstream O2 sensors and just reset the DIC to remove them when they pop up. I have hi-flow metal matrix cats and the codes come back now and then. The downstream O2s just measure the cat efficiency and I don't think they cause any pcm changes so the codes don't really mean anything in terms of engine performance like the upstream O2 sensors do.
For everyone that is not an 04, you may get a code saying the cats are not doing their job shortly after installing headers. You may have to clear this code once or twice. If it comes up a third time, go have them turned off. Basically the PCM is seeing a change it does not like. By clearing the code the first time, you're telling it to shut up and accept it. Some PCMs are stubborn and need a second shut up. I've never had one come up a third time.
For you guys with 04s, Random Technology makes an inline adapter that you plug into the rear O2 circuit that keeps the car from through the codes. This does not disable the rear O2s in any way, shape, or form. This year was very temperamental for whatever reason and turning the codes off or using these adapters are the only ways to keep the light off. The adapters are like $25 each I want to say. Any Random dealer can get them. Contact me or your preferred dealer if you're having issues.
rear O2s only measure catalyst efficiency. They have no effect on performance.