I recently went to go get my inspection done on my completely stock '90 Hatch DX 4spd. The first time I went it failed on the hydro carbon reading. The Standard is 174ppm and mine was at 184ppm, my Nox was at 1149 when the Standard is 1258. I didnt want to spend much money so i got some RXP and added the WHOLE bottle to my 1/4 tank of gas, which equates to about 4 gallons. On the bottle it says each oz treats up to ten gallons of gas and there is 2.5 oz in the bottle. So i go back up there after i add the RXP and on the hydrocarbon reading it gets a 117ppm this time but a Nox of 1768ppm. What can i do to change only the Nox reading without affecting the Hydrocarbon level? Im sure i need a new cat but im not going to do a tune up and spend all this money replacing stuff when i know i can just tweak a few things.

 

how is your ignition timing

 

The best thing i would suggest is to get a hook-up if you know anyone.
Or get Cat-Converter that's probably the only thing i could think of.

 

Wtf is Nox anyways?

 

Do not listen to people like this NOx is a known polluter to our atmosphere not that lucky6 cares, he is what makes people look down on the honda scene. Nitrogen oxide which is the visible part of smog is highly affected by timing because it is usually caused when the combustion cylinder temperatures and they are highly multiplied when the cylinder walls reach over 800 or 1200 degrees (cant remember exact number). That is why i ask how is your timing both mechanical and Ignition timing to advanced mean that you will get high nox numbers if u retard your timing you will lower your nox numbers, but dont retard timing to much as you will fail under a timing light test.

ps nox info http://en.wikipedia.org/wiki/Nitrogen_oxide