MJR
NAXJA Forum User
- Location
- Costa Mesa, CA
JohnX said:Gotta disagree guys. The only failure is on NOx...A CAT is not the answer. And having it hot will only increase the NOx. Hot motor is to get rid of HC's which he is not high on.
Wrong!. Here's some reading material and a link. The following is from this site http://autorepair.about.com/cs/generalinfo/a/aa080401a.htm It is likely he got the wrong cat. NOX is created by high combustion chamber temps so a overheating engine or lean running can make the problem worse. So an O2 sensor could help along with regular service (tuneup/cap/rotor/wires and a combustion chamber decarb if needed) and a good cat conv.
"Catalytic converters can either be an oxidation or three-way type. Oxidation catalysts convert carbon monoxide (CO) and hydrocarbons (HC) to carbon dioxide (CO2) and water, but have little effect on nitrogen oxides (NOx) and particulate matter. Three-way catalysts operate in a closed-loop system together with a lambda, or oxygen, sensor to regulate the air/fuel ratio on gasoline engines. The catalyst can then at the same time oxidize CO and HC to CO2 and water while reducing NOx to nitrogen.
Most cars today are equipped with a three-way catalytic converter. The term Three-way refers to the three emissions it helps to reduce, carbon monoxide, hydrocarbons or volatile organic compounds (VOCs) and NOx molecules. The converter uses two different types of catalysts, a reduction catalyst and an oxidization catalyst. Both types consist of a base structure coated with a catalyst such as platinum, rhodium and/or palladium. The scheme is to create a structure that exposes the maximum surface area of the catalyst to the exhaust flow, while also minimizing the amount of catalyst required."
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