Questions and Answers
Two years ago when I had my first emissions test it failed the limit for nitrous oxide (NO). The limit for my vehicle is approximately 1000 ppm. The test results was 1200 ppm. All I had to do was spend $200 in repairs and I got a conditional pass. I had the fuel injectors cleaned and the O2 sensor replaced. The values dropped but not within specifications. Now, two years later, I need to have the test performed again, only this time I must fix the problem before I get a pass certificate. What can I do to reduce the NO emissions?
Emissions Test
Q. Hi Vincent. I live in Ontario Canada. We have a drive clean program that requires owners to have their vehicles tested every two years for emissions. I have a 1992 Cheep Cherokee with a 4.0 engine. It runs great.
Mark
A. The two things that reduce NOx emissions are the catalytic converter and the EGR valve. The EGR reduces combustion temperature to reduce the formation of NOX and the converter converts them to something less harmful.
I would pull the EGR off and make sure the passages are clear and wide open. The converter would have to be replaced.
