Fail emission

PCHOMINSKI

MEMBER
HONDA CIVIC

Honda Civic 1995 1.6L VITEC 172k miles
First time failed smog marginally on HC: 15mph 97/92 ppm and 25 mph 57/57 ppm. CO was within smog limits but high 0.32 and 023%. NOx was 439/716 and 168 - quite high. Car was hard to start at hot. Computer show code 6 = ETC. I repalced ECT and HO2S. I also repalced engine oil Quaker State 10/30 with fully syntetic Mobil 10/30. Compression is between 12.5 - 13.0. Ignition timing and Vallves were within spec.
Second smog indicates about 1.5 to 2 times higher HC, CO and NOx and failed now on HC, CO and NOx.
I am going to replace catalitic converter and come back to Quaker State oil. But I can not locate any EGR. Does this Honda has EGR and if yes where this is located. Is it better to use high octan gas for lower HC, or is it a risk for even more unburned gas?
Any sugestions will be appreciated. Thanks, Paul

2 Replies

PCHOMINSKI

MEMBER
17 POSTS

I did not get any advise yet, but I solved the problem and would like to explain how.
When I removed catalitic converter, I saw that it was very "dirty" inside. I replaced catalicic converter and now smog ( California) are very good: HC 32/92, CO 0.06.0.54 NOx 6/716.
When I first replaced O2S and all emission values went up by 1.5 to 2 time can be explaned. Old O2S sensor was also covered by "dirt" and was less sensitive to Oxygen. ECM was adjusting very lean mixture in order to compensate for unsensitive Oxygen Sensor. With new O2S mixture was again adjusted to stechiometric value and emission with not working catalitic converter became worse.
I hope that my explanation might help others.