Does DFCO truely cut off the fuel?

[niky]

From what I recall, some systems still inject fuel during DFCO, but the amount of fuel injected almost negligible.

That's some. Others shut the injectors off completely.

[RobertISaar]

if injectors are no longer being commanded open: DFCO.

anything else isn't DFCO. what exists in what is beyond me except for GM applications. GM likes to go from a small fuel flow(coasting down with closed throttle), then filter out injector PW towards 0.00mSec, it isn't an instant drop to 0 since it can cause a really abrupt and noticable effect on vehicle momentum. instead, the engine does temporarily(over a period of much less than a second, BTW) run increasingly lean until a complete lack of injector pulses happen. automatic cars seem to filter out the fuel more slowly than manuals, but it is still pretty quick.

other OEMs MAY follow a similar scheme, but i can't comment on it.