If you live in a state with emission standards, you should have thresholds printed directly on the emission test results for OBD systems. My OBD-II does not print thresholds, however. It only shows values from my actual test. The chart excerpt below shows some typical cut-off values. Feel free to read the actual article to understand more about what the chart’s values mean.
[quote=“excerpt from: aa1car.com/library/tr1196.htm”]
EMISSIONS CUT POINT CHART
Model year…Typical Cut Points…Well-tuned engine
…CO%…HC ppm…CO%…HC ppm
pre-1968… 7.5-12.5… 750-2000… 2.0-3.0… 250-500
1969-70… 7.0-11.0… 650-1250… 1.5-2.5… 200-300
1971-74… 5.0-9.0… 425-1200… 1.0-1.5… 100-200
1975-79… 3.0-6.5… 300-650… 0.5-1.0… 50-100
1980… 1.5-3.5… 275-600… 0.3-1.0… 50-100
1981-93… 1.0-2.5… 200-300… 0.0-0.5… 10-50
1994 & up… 1.0-1.5… 50-100… 0.0-0.2… 02-20
[/quote]
Below are actual Emissions Test Results for my two cars. One is older, from 1994 with no OBD-II connection and has thresholds. The other is a newer 2007 with OBD-II connection and has only pass or fail. Finding threshold values for the state of Georgia turned up nothing. It seems they might be a secret. haha
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As previously stated, these numbers do not really translate to in-game numbers. Obviously, however, the closer you get to 0.00, the better your emissions! I aim for under 80 on my newer engines, and for really hard sport tuned engines, 120-150 seems more reasonable.