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Old 01-31-2012, 12:33 PM   #23 (permalink)
SentraSE-R's Avatar
Join Date: Jun 2009
Location: Bay Area, California
Posts: 1,485

Mean Green Toaster Machine - '06 Scion xB
Team Toyota
90 day: 48.92 mpg (US)
Thanks: 56
Thanked 285 Times in 181 Posts
Thanks to everyone concerned with how this will affect my future as a hypermiler. If I've boycotted Exxon for nearly 23 years, I'm not about to emulate it on a smaller scale.

My hypermiling caused the CEL/MIL that I cleared with my Ultra-gauge back in October. Key-off-on toggling with the engine off and car rolling causes multiple cylinder misfire trouble codes for my car - P0301, P0302, P0303, and P0304 - the next time I turn the key on to start the car, even before the engine cranks over. The ECU apparently sees vehicle speed inappropriate with some cylinder functions, and triggers the TCs. My kill switch stopped those TCs, but a kill switch connector came loose in October, I reverted to key-off-on coasting, triggered the TCs, and I cleared them.

For those of you unfamiliar with CA smog testing, the California Air Resources Board mandates our test stations do complete visual, functional, and emissions tests. We can't skate by just on a CEL/MIL not lit, or an OBDII scan for readiness flags set.

The visual inspection checks for disconnected hoses, non-OEM or non-CARB-approved intake/exhaust/header, any alterations that might affect emissions. I ran a WAI for ~2 years, but removed it before the smog testing, because it would trigger an instant fail.

The functional test checks if the MIL is lit, and if not, if the drive cycle readiness flags are set. A lit MIL is an automatic fail. A readiness flag unset is also a fail. That's what my xB failed. I hadn't completed at least two drive cycles. One was the catalytic converter drive cycle. The other was the evaporative emissions purge drive cycle.

There's a lot of misinformation out there about passing the drive cycle monitors. Some people think you need to drive a car 100 miles. Some say it can take weeks and thousands of miles. In my case, 4 months and 800 miles of P&G wasn't nearly enough. The Scion community found the answers.

In my case, the cat drive cycle is 15 minutes of steady driving between 60 and 100 kph (~37-61 mph). I hadn't done that in 4 months! The evap cycle starts 5 hours after the ignition key is switched off, if coolant temperature is below 90 degrees. If not, it tries to start 2 hours later, etc.

I went out and drove up the nearest highway at 55 mph for 15 minutes, turned around and drove back at the same speed, and went back to the smog test station. I'd set the cat monitor readiness flag. They told me to drive 50-60 more miles, and the evap flag would set. I knew it would set overnight, so I drove home and parked my box. It passed the next morning.

Finally, we're ready to talk about CARB emissions testing, and to determine whether my driving causes more pollution than the average Scion xB.

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 12:43 PM..
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brucey (01-31-2012), mcrews (01-31-2012), mort (01-31-2012), Piwoslaw (01-31-2012)