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Old 01-31-2012, 12:49 PM   #26 (permalink)
SentraSE-R
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Join Date: Jun 2009
Location: Bay Area, California
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Mean Green Toaster Machine - '06 Scion xB
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The CARB emissions test goes something like this. The smog test operator drives your car onto a set of rollers and sticks a sniffer up its tailpipe. The sniffer is connected to a test equipment computer. The op lets your car warm up. In the summer he has a big fan to blow on your radiator. I made sure to remove my grill blocks for the test.

The op enters your car's data. The computer looks up the allowable emissions for your year/make/model/engine/transmission. At some point, a drive cycle begins, where the op has to have the car in gear, driving the rollers, watching the computer screen, keeping the vehicle speed/rpm between two lines. That's where the ~1700 and ~2800 rpm test values come from.

As you can see from the scanned test results, average HC is 4 ppm at both low and high rpm, and my car initially tested 62 and 16 with 64 ppm max to pass. That's >15X normal, and 4X, respectively, with the cat lit. On the retest, my car tested 39 and 14 ppm. That's still nearly 10 times the average at low rpm, and 3.5X at higher rpm for HC.

NO isn't much better. The average car tests 16 ppm at low rpm and 18 ppm at higher rpm. My xB initially tested 101 and 89 ppm, ~6X and ~5X the average. On the retest, my car tested 105 and 74 ppm, ~7X and ~4X the average. Again, this is with the cat fully lit.

My car's CO emission numbers were 6X and 2X the average car on initial testing, and 2X and 1X the average on retest.

I've got some errands to run for a few hours, but it's clear my car has a problem. It is well-maintained. Spark plugs were replaced <10k miles ago. Oil is 5W-20W synthetic. Air filter is clean.

Mech, I'm pretty sure the O2 sensor heat stays on during coasting, since my kill switch only cuts the fuel injector common hot wire.

Tradosaurus, no, where I happen to live doesn't address the problem at all.
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Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg

Last edited by SentraSE-R; 01-31-2012 at 12:55 PM..
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