Re: O sensor knowledge?

My area began emission testing last year. The car passed with flying colors. Yesterday it passed again, but the results were very different this year....mainly the CO%.
The standard is 1.20: High RPM last year was 0.01, this year 1.08. Low RPM was up from 0.03 to 0.13.
The HC was a bit different too:
standard is 220: last year at High RPM the reading was 45 and 47 at low RPM. This year 17 at High and 100 at Low
The other test results are similar to last years results. This emissions testing is a new ballgame for me, so I'm at a loss to know what these results are pointing to?
Not enough information. How was the car checked? Thee are two types (maybe more) methods of testing depending on the year of the car. New ones you just plug in the computer, older ones need a probe in the exhaust so the converter will give a different reading depending on how hot it is.
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Probe up the exhaust pipe. The engine was at NOT. The testing took 15-20 min. Long time to just sit inside idling.....
Dave S(Texas)
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Prior to OBDII cars I would try to run on a freeway for 10-20 miles to get it good and hot. It could also be differences in gas from last year. There are many variables. You need to scope the O2 sensor to verify it's status.

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The long idle can run up the numbers. I'm not sure about our new system, but under the old, if you failed at idle, they put the car on the dynamometer and ran it up to about 50 mph for the test.
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No dynos used here....not yet anyway. I intend to replace the sensor. Shopping for the piece has found a wide price range. From $21.43 to $65 for the same GM or AC Delco unit! The low price is from a online GM dealer in Calif. I've emailed that business asking if the price is correct/the sensor is for correct my vehicle(supplied VIN). I want confirmation first. Had a problem with pricing last year with a different online GM dealer. Website I ordered through showed a price, but when the part arrived the invoice was $15 higher. The business promised to fix it, but never did, so I had to go through my cc company to get the money credited back. The switch I bought was right, but that dealer lost my business.
The sensor in the car now has over 2K hours on it and replacing it is the right thing to do.
Thanks for all the help! I learned stuff I need to know and I appreciate all the info!
Dave S(Texas)
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