why no cel with a godspeed dp and all other u get 1
08-26-2003, 11:09 AM
#3
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Location: San Diego
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Godspeed and PDE both have ways of circumventing the CEL light.
In the case of Godspeeds's pipe, it has a small piece of catalytic convertor material in there around the sensor IIRC. That is enough to not throw the CEL.
The PDE removes the sensor from the mainstream exhaust flow and only gives it s a fraction of the exhaust sampling. Thus no CEL.
Others just put the sensor in plain view of the exhaust gasses.
In the case of Godspeeds's pipe, it has a small piece of catalytic convertor material in there around the sensor IIRC. That is enough to not throw the CEL.
The PDE removes the sensor from the mainstream exhaust flow and only gives it s a fraction of the exhaust sampling. Thus no CEL.
Others just put the sensor in plain view of the exhaust gasses.
08-28-2003, 06:52 AM
#5
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Location: 12.9 / 105+
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Car Info: black my03 5mt wrx s/w
no, it would not.
the p0420 code gets thrown when the ECU determines that the front and rear O2 sensors are "tracking" each other. with a properly functioning cat, the rear O2 sensor would be an integrated function of the output of the front sensor. in other words, it would appear very "smoothed out." in essense, the cat achieves this effect by acting like a storage resevoir for the ingredients of combustion, taking some out here, and adding it back there. the net result is cleaner emissions.
by using a small piece of cat material in between the exhaust gasses and the O2 sensor, the pipe makes the sensor react in the same way it would were the cat in the entirety of the exhaust flow, sidestepping the p0420 code.
it should be noted that the ECU will "test" for the p0420 code only once certain criteria are met. for example, coolant temps must rise by 40 degrees C, a certain amount of time must be spend motoring under 40mph, then above 60, etc. if these criteria are met, then the ECU calls it a "trip." this is why codes seem to "appear" at random--the cats are only tested during a trip. if you only drive 5 minutes to work every day and you keep it under 40 mph you will NEVER trigger a p0420 code!
hth
ken
the p0420 code gets thrown when the ECU determines that the front and rear O2 sensors are "tracking" each other. with a properly functioning cat, the rear O2 sensor would be an integrated function of the output of the front sensor. in other words, it would appear very "smoothed out." in essense, the cat achieves this effect by acting like a storage resevoir for the ingredients of combustion, taking some out here, and adding it back there. the net result is cleaner emissions.
by using a small piece of cat material in between the exhaust gasses and the O2 sensor, the pipe makes the sensor react in the same way it would were the cat in the entirety of the exhaust flow, sidestepping the p0420 code.
it should be noted that the ECU will "test" for the p0420 code only once certain criteria are met. for example, coolant temps must rise by 40 degrees C, a certain amount of time must be spend motoring under 40mph, then above 60, etc. if these criteria are met, then the ECU calls it a "trip." this is why codes seem to "appear" at random--the cats are only tested during a trip. if you only drive 5 minutes to work every day and you keep it under 40 mph you will NEVER trigger a p0420 code!
hth
ken
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