sam12345

iTrader: (1)

I just had my emissions test done and I passed but I wondered what each number can tell me of the condition of my motor. Can anyone with the knowledge enlighten me? Here are the numbers

High speed emission results 2500 RPM

HC(PPM) 16
CO% 0.12
CO2% 15.4
O2%. 0.2
NOx (PPM) 0.00
Dilution (%). 15.5

Low speed emission test. 640 RPM

HC(PPM) 40
CO% 0.49
CO2% 14.7
O2%. 0.8
NOx (PPM) 0.00
Dilution (%). 15.2


Thanks

Shmee

iTrader: (3)

Basically you had a very simple test done, a steady state rpm test which would simulate a highway cruise and an idle test.

HC is for hydro carbons and is the amount of unburnt fuel coming out the exhaust, lower is usually better and suggests a complete burn and better fuel economy.

CO% denotes the quality and completion of the burn. Every car is different and some cars run better at higher CO while others run best at a low CO.

CO2 is a byproduct of the quality of burn and the lower the number the better.

O2 is the remainder of oxygen from the burn and is not an accurate tool to determine the health of an engine.

NOx is one of the most important numbers but it looks like they don't test it. NOx is what produces photo chemical smog or "smog." High NOx typically suggests a malfunctioning EGR system or a pre-ignition event if excessively high.

We don't have dilution up here so I'm not 100% sure about that one.


Usually they, or they do up here, give you a reference to the same year/make/model for comparison like an "average passing reading" for your car.

The numbers suggest to me that its in good shape but with the specs, I'm just guessing.

RA40

iTrader: (6)

Miles on car?
Mine were pretty similar give-take in some readings. 173K miles.

15MPH test

HC(PPM) 21
CO% 0.04
CO2% 14.5
O2%. 0.0
NOx (PPM) 0.00

25MPH test

HC(PPM) 2
CO% 0.01
CO2% 14.6
O2%. 0.0
NOx (PPM) 0.00

sam12345

iTrader: (1)

Mine has 160k it's a 1992 ls400 OBD1