I have a 93' Civic LX, first time I had to get it smogged and it failed with sky high NO emissions, but everything else was well within the limits which made me research why this could be, i read all about what an EGR system does and came to the conclusion, by looking at the numbers i just didn't have one....after having a few people including myself look at the engine we couldnt find one even though the book i have (haynes 92-95 civic & del sol) claims there is one, i called pacific honda and they said that it appears they come without one....no system at all, so im now thinking the cat must be bad but how can that be when just the NO levels are way high and everything else is fine? the smog station is 5 blocks from my house, the car didnt even have a chance to warm up before it was smogged - the cat was still cold and it passed everything but NO? i have a new cat sitting in the living room but i want to make sure thats the problem....heres the numbers from the smog printout....

15mph -
CO2 - 15.24
O2 - 0.18
HC - MAX - 97, AVE - 21, mine is 60
CO - MAX - .59, AVE - .06, mine is .09
NO - MAX - 731, AVE - 150, mine is 1808
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25mph -
CO2 - 15.22
O2 - 0.12
HC - MAX - 62, AVE - 13, mine is 16
CO - MAX - 0.59, AVE - 0.05, mine is 0.02
NO - MAX - 798, AVE - 136, mine is 1181

seems that is the cat was bad/going bad all the numbers, especially the hydrocarbons would be high.....but seeing as the cat was cold it puzzles me even more, unless the other gases burn up in the cat at a lower temp and the NO needs the cat to be really hot....im lost, anyone? does the 93 civic have one of those 3-way cats since it appears to have no EGR system? will replacing it most likely make it pass? thanks

edit - we changed the fuel filter, oil/oil filter, pcv valve & air filter prior to smog

 

Get a bottle of GTP or Isoheet(I think thats the name) and get a good 10-20 minutes of good driving in. A couple WOT starts or anything to heat the cat up before you goto get it smogged.

 

hmmmm well i talked to someone else at pacific honda and he said that its true, some civics didnt come with an egr system and theres other components that create an EGR like effect and high NOX could be a number of things, like clogged injectors, not enough fuel getting to the chamber etc....because NOX is created by very high combustion chamber temps and fuel cools them temps down so getting more fuel into the chamber will cool it down but will also raise HC's.... seems like a big headache. $240 just for an estimate from them, please....