code P0420: Cat Efficiency
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code P0420: Cat Efficiency
just had my 3 inch megan racing downpipe, helix 3 inch hi-flow cat, and megan racing catback exhaust installed and after about 1 week the car threw this code...think its a one time thing or will this continue to happen? is there a fix? maybe with dynoflash or one of the others taking into account my new exhaust? will this affect performance at all??
any info would be great thanks!!
any info would be great thanks!!
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Its the High flow cat and yes there is a flash for it out there. It shouldnt affect performance, the cel just goes on when there is a big difference between the the two sensors. It might go off, but will just probably stay on untill you replace the high flow cat or get a reflash.
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Originally Posted by Eon
....the cel just goes on when there is a big difference between the the two sensors.
SC~
#4
Originally Posted by Secret Chimp
I thought the light comes on when there ISN'T a big difference between the before and after cat O2 sensors? ie....no difference in the readings = a catalytic converter that isn't scrubbing the exhaust properly. But I could be wrong.
SC~
SC~
My 2 cents
Last edited by Guack007; Jul 29, 2004 at 10:20 AM.
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ok well im not so concerned, but when you do have a check engine light on, does the car automatically slow down performance... retard timing or whatever because it thinks something is wrong with the car? thats when i would care....
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I think it does! The computer would probably run leaner and retard timing, in the effort to prevent Cat meltdown. the computer doesn't know that the cat is missing. Just get an O2 simulator.
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#9
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This problem has come up many times.
Check this thread for an easy mechanical solution:
https://www.evolutionm.net/forums/sh...ad.php?t=62524
Look for the posts by DerekW #14
This is what I did and no CEL since
Check this thread for an easy mechanical solution:
https://www.evolutionm.net/forums/sh...ad.php?t=62524
Look for the posts by DerekW #14
This is what I did and no CEL since
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awesome!
you rock man.
btw, this wasnt a question of me being lazy and not doing a search for it... i had no idea what i would be searching for!
thanks for pointing me in the right direction!!
you rock man.
btw, this wasnt a question of me being lazy and not doing a search for it... i had no idea what i would be searching for!
thanks for pointing me in the right direction!!
#11
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Yea. Who would think to search for cat CEL problems by typing "spark plug anti foul" .
I can't remember how I stumbled over it; just remember that when I threw that code I read about everything
that had "cat" and "cel" in it.
I can't remember how I stumbled over it; just remember that when I threw that code I read about everything
that had "cat" and "cel" in it.
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I am pretty sure there are many fixes out there for this, o2 simulator, reflash, sensor positioning, etc. But they won't change the fact that the car probably won't pass emissions. They prevent the CEL from going on, but they don't change the underlying problem of the excessive emissions.
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Originally Posted by inariv5573
I am pretty sure there are many fixes out there for this, o2 simulator, reflash, sensor positioning, etc. But they won't change the fact that the car probably won't pass emissions. They prevent the CEL from going on, but they don't change the underlying problem of the excessive emissions.
lolol underlying problem.
i think my car wasnt going to pass inspection when i tinted the windows a year ago....