DFM disabler released

RG23RST said:

How did this ridiculous rumor get started? Read GMs own service description of DFM operation that was posted earlier in this thread. DFM is NOT active during deceleration fuel-cutoff mode aka what you experience when coasting down with quiet exhaust. The engine re-fires at 14mph slowing down if you continue to coast.

DFM IS NOT ACTIVE DURING DFCO. Not sure what else to say. The solenoids aren’t energized and the lifters aren’t being de-activated. DFCO is normal operation whether the engine has DFM or not. My company 2500 with the L8T does the exact same thing. If you want to remove this behavior you need a full tune.

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Scarey said:

Weather is called Dfm or dfco, doesn’t matter, when you take your foot off the gas all the lifters collapse keeping the valves closed. In steady state cruise the system collapses some lifters to take some cylinders off line. This whole discussion is about lifter collapse. We all want a normal lifters and no lifter failure because of a designed collapsible lifter. We just want a normal fire breathing v8 all the time.

Here’s a quote from carbyte people on the at4 forum.

The 0-cylinder mode activates DFM (valves are not moving) and shuts off the fuel. Carbyte prevents both from happening once the 40mph condition is met (as explained in our previous post), with the only downside of using negligibly more fuel.

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Antonm said:

Put the truck in L9 (which actually disables DFM) and that doesn't happen. Cutting off fueling while coasting is not new (even my mechanical P-Pump Cummins engines from the 90's do that). Part of the current DFCO is to allow the lifters (all of them) to collapse which is thing we all just want disabled and are not getting.
So sure, one could argue the semantics that DFCO its separate from and not directly part DFM, buts its a stretch as it does request DFM to activate and collapse the lifters (which is the main thing we all wanted to stop from ever happening). If DFM were "disabled" then when DFCO requested it, it wouldn't do it, so DFM is not disabled.

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Scarey said:

Just read Antony response. I agree, we are all trying to find the same answer which will help us each make our on decision on hw we want to deal with this crappy lifter thing. Maybe carbyte and range want to chime in here? You know they are lurking.

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RG23RST said:

NO LIFTERS ARE DEACTIVATED DURING THIS MODE. NONE.

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Antonm said:

the lifters collapse on deceleration
because
DFCO orders the DFM lifters to do so.

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Marky Dissod said:

'The conditions below MAY be reasons for inhibiting deactivation'
'Decel Fuel Cut Off is active'
As in, MAY, or may NOT.
Any English teacher or proofreader will understand that DFCO might allow cylinder deactivation,
or that some DFCO events might also coincide with some cylinder deactivations.

DFCO and cylinder deactivation are two separate different UNRELATED things.
However, they are NOT mutually exclusive.
(I.E.: I MAY achieve turgidity even when NOT distracted by the thought of Milana Vayntrub in a bikini.)

Antonm, DFCO does not cause cylinder deactivation either.
Their occurrences can overlap without one causing the other, however.

Since Antonm is not going to win any money by RG23RST being wrong,
and RG23RST is not going to win any money by Antonm being wrong,
ultimately, Range has already admitted that they did NOT deactivate 0-cylinder mode,
RANGE IS WRONG, and Milana Vayntrub is gorgeous.

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