Quote:
Originally Posted by parablooper
Of course for most of you that's common knowledge. My question is, what do they mean by MODERN cars? As in, anything past 1985 modern? Or like, 2013+ model year BMWs and high-end cars that have engine stop/start and that kind of stuff? How would you know if a given car had the injector shutoff feature? Would it say in the manual? Could you listen for it? For the record I'm trying to teach someone how to drive a late-90's Nissan Maxima (A32) for better MPGs and I need to know which technique would be better.
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You'll probably find that anything EFI does it, it was a fairly early trick to aid economy. The question then is how useful that feature is for that particular vehicle. Most older cars will only DFCO if RPM is over 2000, so in my Jeep Wrangler, that's next to useless as I'd rarely be drivng at that kind of RPM, (the downshift seems hardly worth it either).
On my Renault I also need 2000rpm to enter DFCO but with it's low gearing it's far more useful. DFCO generally cuts off again at 1500rpm. Given the fairly narrow DFCO engagement envelope of older cars, I wouldn't confuse someone I'm trying to teach too much with it. Those parameters can also be dependent on road speed and RPM so it can be quite confusing if you don't have instruments.
On my Fiat I'm able to enter DFCO at just about any speed over idle in all but first and second.