emission test results

March 11, 2010, 12:09:04 AM

so my 1984 cougar with 119,000 miles passed new jersey emission test inspection. i was wondering if anyone here could explain the test numbers ... the inspection station was not very friendly .

the idle test was
HC ppm 132 reading... the standard is 220
CO% 0.03 reading... the standard is 1.20
CO2% 7.72
O2% 9.29

the high idle test was

HC ppm 122 reading .... the standard is 220
CO% 0.00 the standard is 1.20
CO2% 8.26
O2% 9.20

thanks
eddie

emission test results

Reply #1 – March 11, 2010, 06:31:53 AM

It's been a while, but if I remember correctly...

HC (Hydrocarbons) are unburned fuel.
CO (Carbon Monoxide) is partially burned fuel
CO2 (Carbon Dioxide) is a byproduct of combustion
O2 (Oxygen) is an indicator of exhaust system integrity

An engine that is running lean will have very low CO readings, and high HC readings. This is because it will burn all of the fuel in its cylinders except when a lean missfire occurres.

An engine that is running rich will have high CO and high HC readings. The high CO readings stem from it being unable to completely burn all of the fuel in the cylinders due to a paucity of oxygen, while the high HC comes from the leftover raw fuel.

A third pollutant was created when we started making engines run clean, called NOx. NOx is really a combination NO and NO2 and stems from the higher combustion temperatures created with the leaner mixtures utilized in the modern pollution controlled vehicle. The solution to NOx was the EGR or Exhaust Gas Recirculation valve which recirculates exhaust gasses back through the combustion chamber to cool it to a point low enough to avoid the creation of NOx gases.

Shiny Side Up!
Bill

emission test results

Reply #2 – March 11, 2010, 08:59:10 AM

do they still do the idle test in Jersey? I thought they only did the 2500RPM test to pass the emisions.