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Old 04-09-2011, 02:53 AM   #10 (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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DFCO is definitely programmed differently for different cars.

From the repair manual, and confirmed by observation, my 2002 Nissan Sentra SE-R went into DFCO when engine rpms were >2500 rpm, while my 2006 Scion xB goes into DFCO with rpms >1500 rpm. In effect, the Sentra wouldn't enter DFCO at speeds below 65 mph in top (6th) gear. The Scion, OTOH, enters DFCO at any speed above 35 mph in top (5th) gear.

Worse yet, once in DFCO, the Sentra stayed in open loop for a full four minutes after exiting DFCO. So any fuel saved by coasting in gear was wasted during the next four minutes of open loop driving. The Scion, OTOH, resumes in closed loop after DFCO. It has no DFCO penalty. I don't think the difference is Nissan v. Scion philosophy as it's 2002 v. 2006 programming progress.

My wife's 2006 AT Hyundai Elantra doesn't have DFCO, from what I can see.
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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
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