2nd O2 ByPass

[Brian5475E]

Available at your local automotive store. Spark Plug Non Fouler PN 42009 ($4.99)
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You now need to drill out 1 of the non foulers using a 1/2" drill bit. When finished this is what it will look like.
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Side by Side comparision of the orignal and now modified non foulers
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o2 Sensor inserted in the modified non fouler
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Second, unmodified non fouler now installed on modified non fouler
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Original non fouler->Modified non fouler->o2 sensor
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Fully installed
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The idea behind it is when you remove the cat the 2nd o2 sensor is going to have too much crap reaching the sensor that isnt filtered out, which will make it think the cat has gone bad. What this does is it moves the o2 sensor further away so a limited amount of exhaust gets to the o2 sensor, it is a VERY little ammount that actually gets to the sensor but as long as it is considerably less than the primary o2 sensor then it wont cause a CEL.

from (http://www.k-series.com/forum/showthread.php?t=8833) pics rehosted by me incase the thread/pics disappear.