Quote:
Originally Posted by 88hf
Ok, now I could be wrong... but the 96 HX has a very expensive upper O2 sensor (wideband?) and I think what we are looking at is the lower O2 sensor. I'll know more for sure this weekend.
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Yes both the civic vx and civic hx (honda's US federal lean burn cars) have the 5 wire wideband upper sensors to monitor the lean burn condition. The civic HX also has a standard narrow band 4 wire sensor after the cat (downstream) that really is only a OBDII requirement that monitors cat function.
I am wondering now why the D15b/d15d7 3 stage vtec engine does not have a wideband if it truly is a lean burn engine? Or maybe the wideband in the US cars only is there only to closely monitor the mix for emissions reasons? I know lean burn cars by nature have higher NOx output. I wonder if the widebands are to keep NOx in check (probably running on the edge of being legal) for US emissions regulations?
Sorry to hijack your thread. I really find this stuff interesting and am just trying to find a few answers.