DFM disabler released

jfoj said:

I would say there is an improvement in acceleration and transmission smoothness, or at least not having the engine hunting and turning cyclinders back on during tip in throttle and acceleration. This then equates to less or no transmission hunting as well.

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THIS is what I'd expect.

Big difference between not firing the fuel injectors on decel (which is a good thing) and telling the lifters to collapse and not open the valves, which is what DFM does that the Range Tech device leaves on.
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jfoj said:

Just so everyone is aware, and Range did not have this info on their website in the description, when the Range 007 device is plugged in the Evap and O2 Sensor Emission Readiness Monitors will not become Ready. So if you live in an area that requires Emission Testing, you will need to remove the Range module for the Emission Readiness Monitors to fully become Ready prior to Emission Inspection, otherwise you will not pass an Emission Test. This is based on OBDII Emission Inspections.

I emailed Range and they confirmed this is the case, but again, nothing on their Website about the Readilness Monitors. Unclear if this will impact OBDII codes from triggering in the future, unclear if OnStar monitoring will pick this up. Based on the price point, this is clearly some form of Spoof module rather than a sophisticated microprocessor that alters the data stream the inhibit AFM.

So BEWARE, you WILL NEED TO REMOVE the Range device prior to Emission Testing.

Overall I am fairly happy with the performance of the module, but so far I only have about 300 miles using it.

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Great info here @jfoj , thank you.

I had my OBD WiFi adapter going and thought everything looked normal as far as readiness tests last time I looked (with the range installed) but will check that out. Not a big deal to pull it though before NYS inspections.

Wonder if the carbyte uses the same technique.

Reply from Range after I noticed issues with the Readiness Monitors on the Range 007.

That is going to be normal. You would have to disconnect the module and do a drive cycle for the systems to show ready.

Antonm said:

No, not in an otherwise stock vehicle there isn't anyway. Our 6.2 High Country Tahoe didn't have any acceleration or transmission smoothness issues before the Range Tech device.

Before the Range Tech device, if you turned the radio off, and told the kids to be quite, you might, maybe, be able to tell when it deactivated cylinders if you tried real hard, and even then it was a maybe. I'm sure with an aftermarket exhaust it would be much more noticeable, but the stock exhaust is pretty dang quite.

And I agree with your last statement, it is a complete waste IMHO, unless you have a louder aftermarket exhaust, and the sound of the cylinder deactivation bothers you.

If Range Tech would make an actual DFM disabler (you know, something that just turns the dang DFM off, like how hard its that, just turn it off), then I would be first in line to get one.
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If you don’t notice DFM I would agree you’ll perceive it as a waste. If you do notice the vibration, hesitation, shudder, and all the other badness with DFM, I assure you you’d have the opposite impression.

Interesting to note, I’m driving a 2025 Silverado right now while my Tahoe is getting some warranty work done. For the first 500 miles or so it ran really nice. Peppy, didn’t notice DFM at all. It has 750 miles now and I’m starting to notice it. Its feel, not sound.

If one of us could figure out what variables are involved for those who say it’s undetectable versus those who can’t stand it, we’d be heroes.

Antonm said:

Why do you think the Range device will "potentially avoid lifter failure" when it still has the DFM functioning during the 0-Cylinder mode (which is literally every time you drive the vehicle and come to a stop)??? Having the 0-Cyilder part of DFM still enabled totally negates any potential lifter saving or reduced failure it might have.

Basically the one and only thing its good for is making consistent exhaust sounds for those with modified exhaust systems. Which I guess if that's something you care about then sure, the range tech device works fine.
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Because the lifters do not lock and unlock. They remain locked. You apparently have not had a lifter collapse and waited a month to get new parts. My lifters remain locked during decel—which the rest of my post stated. All 8 all the time.

i have both range 007 and carbyte. I’m happy I have choices. Question is, and I asked on another thread, are these the only choices we have? It sounds like there is not an option for a tune on the, roughly 22 models on. Is this correct, no other choices?

Kpwweb said:

Because the lifters do not lock and unlock. They remain locked. You apparently have not had a lifter collapse and waited a month to get new parts. My lifters remain locked during decel—which the rest of my post stated. All 8 all the time.

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But you’re wrong, you absolutely do not have all 8 all the time (lifters still unlock during decel). There is no special programming for the z71 compared to any other model.

The reason you feel the slow down is because the DFM is unlocking and collapsing the lifters on deceleration. If the lifters were to remain locked the effective deceleration would be lessened.

This change in the way the vehicle feels to the driver is why Range tech left that part on, because they assumed most of their customers are stupid and would complain about the change in the driving experience. So they completely negated the primary reason most people want a DFM disabled in the first place.
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Antonm said:

But you’re wrong, you absolutely do not have all 8 all the time. There is no special programming for the z71 compared to any other model.

The reason you feel the slow down is because the DFM is unlocking and collapsing the lifters on deceleration. If the lifters were to remain locked the effective deceleration would be lessened.

This change in the way the vehicle feels to the driver is why Range tech left that part on, because they assumed most of their customers are stupid and would complain about the change in the driving experience. So they completely negated the primary reason most people want a DFM disabled in the first place.
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If that is the case, then deceleration would be the same with or without the Range. It is markedly not. Deceleration is demonstrably greater with the Range than without. As Range stated, “some customers will have…”

Why the difference with some and not others?

Kpwweb said:

If that is the case, then deceleration would be the same with or without the Range. It is markedly not. Deceleration is demonstrably greater with the Range than without. As Range stated, “some customers will have…”

Why the difference with some and not others?

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So let me get this straight,,,you think that a piston going to the top of the cylinder with an open exhaust valve every other engine rotation, which will allow the air/gasses in the cylinder to escape out the exhaust system, will provide the same resistance as having both valves closed (because DFM collapsed the lifters) so that every time the piston goes to the top of the cylinder it must compress those gases? Do I have that right?

In a V8, in any given rotation of the crankshaft, with the lifters locked, there would be four cylinders doing a compression stroke and four cylinders on an exhaust stroke when the piston came to the top of the cylinder, so only four of the cylinders would be causing resistance to rotation, or braking force, for every crankshaft rotation. Now unlock the lifters, and all eight cylinders would be compressing air/ gases causes resistance to rotation, or braking force, every time they came to the top of the cylinder.

The whole restricting the exhaust thing is the same principle (different method, but same principle) used the ever popular "Jake Brake" on diesels, seems to help slow them down.
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