I had my emissions done recently, and i failed. i passed everything except for one thing, i cant really tell you what that was but this is what the paper says



result allowed
NOx PPM 1213 1194


can anyone tell me what this means and maybe a solution to fix it.
Thanx BUBBA

 

Eh, first stab would be that the EGR system is not functioning properly.

NOX is caused by high combustion temperatures. The EGR function is to introduce exhaust gas to the cylinders as a means toward keeping the peak combustion temperatures cooler. Sounds goofy, but it works.

If you're not throwing an EGR code, then it's possible that the catalyst is not working to spec. This is another means used to reduce NOX to its nitrogen and oxygen components.

NOX is supposed to be a bad actor toward the ozone layer, so that's why it's considered a pollutant.

The only reason I list EGR over catalyst is that the EGR prevents the bad actors from forming, the catalyst merely serves as the cleanup crew. Either component could be the problem.

Another alternative is to maybe consider moving to a less-densely populated area that is within the regional attainment so sniffer tests aren't required? :-)~

 

well the guy at the shop told me he took a quick look at the EGR valve and said it was fine but i dont know, not a fully educated mechanic(yet)

 

One other possibility came to mind, albeit a low-probability item - if the EGR exhaust gas piping has a leak / split in it - it will be sucking air in which may throw things off.

 

Run the gas down to almost empty, throw a bottle of Techron in the tank and fill up with full premium fuel - ethanol enhanced if you have it in your area - drive it hard till you burn off about 1/2 tank, then take it back for a retest. Try to do the retest after driving on the highway for 30 minutes or so. That result is SO close to allowed this may take care of it.