I failed the inspection for my nox (ppm) on my High Speed Emissions test. The standard is 1240 and my result was 1267.
How can I lower my High Speed Nox (ppm)? on 1994 Honda Civic
Check EGR, and Carbon build-up
ck egr passages for blockage of carbon or timing can be retarded or poss o2 sensor
Globalhelpers suggestion first!! EGR SYSTEM function is very important. Next would be timing as he mentioned , and then be sure the cooling system is in good shape. Last , if high miles (by age I'm assuming it is) maybe a top engine cleaner -get carbon build-up off pistons -lower comp. lower combustion temp=lower Nox.
well said zip man
Thank you.......:) ......never mind.