Emissions Test Results... Failed/Passed Results

Just an FYI for those interested in Emissions.

Took my '91 3.1L Pontiac Sunbird in for E-Test and it failed (first set results below). Thanks to various rec.autos.tech posts, the fix pointed to replacement of O2 sensor. I replaced O2 sensor, and all is well (passed with second set of results below).

Just thought I would post my failed and passed measurements as a guide to others.

FAILED Measurements: ASM 2525 CURB IDLE HC ppm 79 121 FAIL 200 197 PASS CO Percent 0.44 0.09 PASS 1 0.04 PASS NO ppm 908 473 PASS N/A N/A N/A

PASSED Measurements: ASM 2525 CURB IDLE HC ppm 79 68 PASS 200 143 PASS CO Percent 0.44 0.03 PASS 1 0.49 PASS NO ppm 908 635 PASS N/A N/A N/A

Reply to
Mark
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I should've included some better 'search keywords' for the future...

high hydrocarbons hydro carbons hydro-carbons

Reply to
Mark

You're still so close to failing that I'd be looking for what else is wrong. Have you checked the cam and ignition timing? Replaced the spark plugs, etc yet?

It's unlikely it's going to get better on it's own, and you're right on the edge of passing now, so I'd be concerned that to oxygen sensor wasn't the whole problem.

Do you have any records on what it should be? (i.e. if you've had it for a few years and saved the other test results, you could use that as a baseline).

Notice how the NO went up, and the CO went up for the idle test.

Perhaps it's running hot and needs a new thermostat and/or coolant temp sensor. It's very likely it doesn't need anything expensive done to get these numbers much lower so you won't have to worry about the next test. In addition, the slightly high HC you've still got will degrade your catalytic converter over time.

In no way do I mean to say that you're a gross polluter or anything like that, just trying to add some info...

Or maybe the plugs just need to be removed and cleaned off.

Reply to
Bob Hetzel

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