Originally Posted by jefhuf
Took my truck in for emissions inspection today and passed without a problem (always a tense moment there)...however, I took a look at my inspection report and was surprised to see the values. He in VA, the HC ppm limit is 125 both at idle and at 2500rpm and the CO% is 1.00 for both. My truck registered 35ppm HC & .01 CO% at idle and 23ppm HC & .02 CO% at 2500rpm. What are others seeing?
For reference purposes, my truck has a 3.9L with about 45K miles on it and I just replaced a cat and installed a "new" (used unit from Tillery) dizzy because my old one died. I also installed some new plugs because I was worried my lack of VSS for over a week may have fouled the old ones. I am getting a little pinging under acceleration with a load (typically up hills) so I assume I need to look at my timing but thought the emissions values were just oddly low.
Jeff, it means your cats and engine are working in an efficient manner.(different from peak efficiency)
HC is hydrocarbon or unburnfuel, your fuel injection system is well coordinated with your ignition timing but not nescesarily optimum. (as you can tell by the ping).
CO is carbon dioxide and it is a by product of combustion of course formed by hot gasses yada yada yada.
so your fuel and engine are doing their best with the info received from the varius sensors, coolant temp, air intake and o2 sensor read out... this passes the cats and the output is what is measured.
if you did not have cats, they were cold (less than 2500 degrees), or defective one of the sensors was failing, or your plugs were fouled, those readings would not be possible...
even with all in working order and you tested before the cats, those readings would be thru the roof.
check out va deq's website, they have lots of good info on emissions.
the link should be on your paper work.