Petersubaru Posted March 5, 2005 Share Posted March 5, 2005 just a question ...why is the O2 sensor placed before the catalytic con. Quote Link to comment Share on other sites More sharing options...
NorthWet Posted March 5, 2005 Share Posted March 5, 2005 To get "raw data". If it were after the catalyst, the results would be affected by the redox products of the catalyst(s). What you want for A/F ratio control is what comes out of the ports. Granted, the difference would be minor, but there you are. Quote Link to comment Share on other sites More sharing options...
incognito Posted March 5, 2005 Share Posted March 5, 2005 Not really northwet.. The reason the o2 sensor is before the catalytic converter is to maximize catalytic converter efficiency by detecting how much oxygen is before the cat so that the computer can maintain a 14.7:1 stoichiometric ratio to maximize catalytic converter efficiency.. There are sensors after the catalytic converter to detect converter efficiency.. Quote Link to comment Share on other sites More sharing options...
subyrally Posted March 6, 2005 Share Posted March 6, 2005 after the cat, the o2 sensor would be worthless to the ecu for tuning the air/ fuel ratio, the only reason they put sensors behind the cats on newer cars is for emissions control, basically to make sure that the cats are working, not to control the engine. Quote Link to comment Share on other sites More sharing options...
incognito Posted March 6, 2005 Share Posted March 6, 2005 the only reason they put sensors behind the cats on newer cars is for emissions control, basically to make sure that the cats are working, not to control the engine. this is correct. Quote Link to comment Share on other sites More sharing options...
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