DFM disabler released

[CMoore711]

Any of you who installed this module also have the AutoStop Eliminator installed? Any conflict between the two with both modules installed?

https://www.rangetechnology.com/products/dfm_module/parts/RA007

@KMeloney Check out the link above if you read more of the details it sounds like the range device eliminates BOTH the auto start/stop and DFM with the single range device.

 

[Kpwweb]

https://www.rangetechnology.com/products/dfm_module/parts/RA007

@KMeloney Check out the link above if you read more of the details it sounds like the range device eliminates BOTH the auto start/stop and DFM with the single range device.

The Range device does eliminate both. However, some of us already have the auto start/stop eliminator installed. I, too, was wondering about both installed and if they would conflict. I am glad to hear there are no issues with both.

 

[KMeloney]

The Range device does eliminate both. However, some of us already have the auto start/stop eliminator installed. I, too, was wondering about both installed and if they would conflict. I am glad to hear there are no issues with both.

https://www.rangetechnology.com/products/dfm_module/parts/RA007

@KMeloney Check out the link above if you read more of the details it sounds like the range device eliminates BOTH the auto start/stop and DFM with the single range device.

Exactly why I asked. I have the ASE installed, and I wouldn't want to uninstall it if there's absolutely no reason to.

 

[CMoore711]

The Range device does eliminate both. However, some of us already have the auto start/stop eliminator installed. I, too, was wondering about both installed and if they would conflict. I am glad to hear there are no issues with both.

Exactly why I asked. I have the ASE installed, and I wouldn't want to uninstall it if there's absolutely no reason to.

I just watched the video of that ASE start/stop eliminator installation, I guess that device is pretty involved on the installation too with the removal of some of the dash trim pieces to the left of the steering and such...

But it's still reversable and you can uninstall it and revert back to stock.

Now Range has a single device that offers both start/stop eliminator and DFM disabler. If it were me I probably wouldn't leave both devices installed regardless if they played nice together. I'd just uninstall the ASE and install the new Range device and list the ASE for sale on here to recoup a couple bucks.

One less aftermarket harness installed seems like the better safer long term option, though it is a little extra work.

 

[Thiccboii]

New here. New owner of a 24 Yukon. I dove deep into this topic and trying to figure out if it’s the best move for me. I came across this YouTube comment and wanted to post it here for discussion. This gentleman brings up a good point regarding the lack of oil flow to the DFM lifters after running this product long term. Link to video:

Granted, the video is about a 19 Silverado but the concept is the same.

Thoughts?

 

[nick14226]

New here. New owner of a 24 Yukon. I dove deep into this topic and trying to figure out if it’s the best move for me. I came across this YouTube comment and wanted to post it here for discussion. This gentleman brings up a good point regarding the lack of oil flow to the DFM lifters after running this product long term. Link to video:

Granted, the video is about a 19 Silverado but the concept is the same.

Thoughts?

I thought about that when I had the AFM disabled with a tune on my ‘17 5.3, the system doesn’t get “exercised.” I did switch back to stock for dealer visits.

The DFM Disabler, to some folks disappointment, allows the DFM to function during deceleration on some rigs, including mine. So it’s still doing its thing but fortunately at a time I don’t notice it or mind.

If I were you with a new ‘24 I’d wait to see what you think. Maybe you’ll be lucky and be one of the people who says it’s imperceptible. If that’s the case, keep it stock, enjoy the slightly better (maybe) gas mileage, and be happy. If you’re like me and the DFM not only is perceptible but also ruins the driving experience of the vehicle on a daily basis you won’t even question whether or not to install the Disabler, you’ll be screaming for it, begging range to ship it faster, and waiting in the driveway for the FedEx truck LOL.

 

[Kpwweb]

I had a previous 2016 tahoe with AFM disabled for about 70-80k miles via a tune. No troubles. Put it back to stock before trade in and no issues whatsoever. I also used a good synthetic oil the entire time.

Cheap oil = expensive problems

 

[WalleyeMikeIII]

If I were you with a new ‘24 I’d wait to see what you think. Maybe you’ll be lucky and be one of the people who says it’s imperceptible. If that’s the case, keep it stock, enjoy the slightly better (maybe) gas mileage, and be happy. If you’re like me and the DFM not only is perceptible but also ruins the driving experience of the vehicle on a daily basis you won’t even question whether or not to install the Disabler, you’ll be screaming for it, begging range to ship it faster, and waiting in the driveway for the FedEx truck LOL.

Hi @nick14226, can you elaborate on what ruins your drive on a daily basis. I guess each one these vehicles are different, but in my Denali (which is so whisper quiet in the cabin I cannot even hear the stock exhaust, and really cannot even hear the engine unless its above about 3500 RPM) the ins/outs of DFM are completely unnoticeable. Even with the windows down, the wind noise easily drowns out any drivetrain sounds. (I Must be one of the lucky ones, or maybe on this trim level, it is less perceptible). Also, after disabling, do you notice any fuel economy differences? I routinely get 21+ MPG on flat highways if I keep her under about 73MPH, did 400 Mile round trip last weekend and got 22.1 on the way there, and 21.4 on the way home.

Anyway, I am not saying you are wrong, just more curious on what characteristics of the DFM in your vehicle make your driving experience poor. In my rig, I set the cruise and life is grand, if I need power, I hit the gas, and there is immediate downshift and the 6.2 comes to life and I am off to the races. In town, I never notice it engaging or disengaging...I'm at 30.5k on the odometer, and things are still smooth as silk. That said, my rig is 100% stock on everything engine/exhaust related.

EDIT: I just re-read the whole thread, see your complaint is primarily shudder/vibration at cruise or gentle throttle application (presumably not enough power demand to reactivate all cylinders?)
Is it possible you actually have the transmission shudder issue, and it is just more noticable when DFM is enabled, vs DFM? Do you have the 5.3 or 6.2? That coule be another factor, as could be your performance exhaust?
All good, seems disabling it helped your application...glad there is a solution that works for you.

 

[nick14226]

Hi @nick14226, can you elaborate on what ruins your drive on a daily basis. I guess each one these vehicles are different, but in my Denali (which is so whisper quiet in the cabin I cannot even hear the stock exhaust, and really cannot even hear the engine unless its above about 3500 RPM) the ins/outs of DFM are completely unnoticeable. Even with the windows down, the wind noise easily drowns out any drivetrain sounds. (I Must be one of the lucky ones, or maybe on this trim level, it is less perceptible). Also, after disabling, do you notice any fuel economy differences? I routinely get 21+ MPG on flat highways if I keep her under about 73MPH, did 400 Mile round trip last weekend and got 22.1 on the way there, and 21.4 on the way home.

Anyway, I am not saying you are wrong, just more curious on what characteristics of the DFM in your vehicle make your driving experience poor. In my rig, I set the cruise and life is grand, if I need power, I hit the gas, and there is immediate downshift and the 6.2 comes to life and I am off to the races. In town, I never notice it engaging or disengaging...I'm at 30.5k on the odometer, and things are still smooth as silk. That said, my rig is 100% stock on everything engine/exhaust related.

EDIT: I just re-read the whole thread, see your complaint is primarily shudder/vibration at cruise or gentle throttle application (presumably not enough power demand to reactivate all cylinders?)
Is it possible you actually have the transmission shudder issue, and it is just more noticable when DFM is enabled, vs DFM? Do you have the 5.3 or 6.2? That coule be another factor, as could be your performance exhaust?
All good, seems disabling it helped your application...glad there is a solution that works for you.

Initially I thought I lost half an mpg but now I'm at, actually slightly better, mpg than pre eliminator. I'm at 15 MPG average (lifted, heavier wheels and tires, summer fuel, etc).
With that comes a billion variables as does the DFM issues. I noticed it before I started mod'ing, but agree, some or all of what I've done may have made it even more noticeable. Quality of fuel, octane, summer vs winter blend, aggressiveness of tire tread (lot of silverado trail boss complaints out there, duratracs / driveline angles). Could all come into play.

With that said, yes, you're lucky and no, I don't think I'm wrong or misdiagnosing it. Read through attached, especially the "Correction" section, it's kind of unbelievable that's all "normal". This is also the TSB I referenced to prove to a previous poster that L9 disables DFM when stated it didn't.

 

[WalleyeMikeIII]

@nick14226, thanks for that explanation. Makes total sense. As I recall, the Z71 available w/ the 5.3 or 6.2 in 2022 as well, correct? Guessing the 6.2 has a bit more gusto w/ cylinders deactivated than the 5.3, so that could also be a difference; you haven't said which engine you have. For sure exhaust mods would make the changes more noticable....bummer it is so obnoxious for you. Glad you have a solution you can live with though.

 

[nick14226]

@nick14226, thanks for that explanation. Makes total sense. As I recall, the Z71 available w/ the 5.3 or 6.2 in 2022 as well, correct? Guessing the 6.2 has a bit more gusto w/ cylinders deactivated than the 5.3, so that could also be a difference; you haven't said which engine you have. For sure exhaust mods would make the changes more noticable....bummer it is so obnoxious for you. Glad you have a solution you can live with though.

Sorry, yes 2022 z71 5.3
The corsa had no impact on the drivability. It’s well designed and eliminates the flapper, but no drone from DFM. Just can hear the cylinders kick back during decel at 14 mph, which again doesn’t bother me. I’ve 6.2 owners with the same complaints as the TSB defines that I experienced, so again, think you’re lucky

 

[djnice]

Related to gas mileage. Before I get the disabler, I've been experimenting L9 VS D with the 5.3 in my AT4 that's lifted. I'm not seeing any difference on various drives. The other day I got 24 mpg in L9 with a mix of city and highway average speed in the 60's. It all depends on the road you're on and how much incline and wind there is. So really hard to evaluate the impact. My life average is in 14's, but that is lots of stop and go. Also, I think the front end aero on the AT4 and Z71 has -2 mpg impact compared to suburbans that I've rented.

 

[Marky Dissod]

Please note: I don't own one of these direct injection engines with the 'How Many Cylinders Now?' bug/feature.
That said ...
There are two situations during which I see MINIMAL harm in this feature being active:
1. 0% throttle decelerations (aka Decel Fuel Cut Off / DFCO)
2. Whenever the engine coolant temp has exceeded somewhere between 221F / 105C & 230F / 110C
(I'm using that coolant temp threshold as a proxy for being in danger of overheating)

1. While you happen to be decelerating @ 0% TPS, you don't need ANY cylinders,
the road is effectively turning the wheels, which are turning the axles, which are turning the transmission, which is turning the engine,
because no cylinders are receiving ANY fuel anyway - so it's kind of a moot point.

2. It should be a well-known fact that Chrysler's earliest attempts at Engine Half@$$ allowed the 4 lazy cylinders to get so cold,
they cracked engine blocks.
IFF the engine is in danger of overheating, running on the minimum number of cylinders needed and varying them moment-to-moment
may help to keep engine temps down in all 8 cylinder sleeves, or at least delay overheating by a minute or two, which may be very helpful

Under the vast majority of normal driving circumstances, however,
there is NO REASON to have Cylinder Confusion enabled *except possibly for the two caveats above*.

This gentleman brings up a good point regarding the lack of oil flow to the DFM lifters after running this product long term. Link to video:

Actually he does NOT.

NOTE: THE FOLLOWING IS *WRONG.
PLEASE CAREFULLY READ THE CORRECTION IN POST #75 BY @RG23RST.
*(The way On/Off lifters work, is when the cylinder goes lazy / Off, oil flow is DENIED to that cylinder's lifters.
So when the engine is in V8 mode, oil is pumping those lifters up, same as it's worked since hydraulic lifters first started replacing solid lifters.)*

On / Off lifters will last longest if they are always left ON / if Cylinder Confusion is disabled.

 

[BacDoc]

Hi @nick14226, can you elaborate on what ruins your drive on a daily basis. I guess each one these vehicles are different, but in my Denali (which is so whisper quiet in the cabin I cannot even hear the stock exhaust, and really cannot even hear the engine unless its above about 3500 RPM) the ins/outs of DFM are completely unnoticeable. Even with the windows down, the wind noise easily drowns out any drivetrain sounds. (I Must be one of the lucky ones, or maybe on this trim level, it is less perceptible). Also, after disabling, do you notice any fuel economy differences? I routinely get 21+ MPG on flat highways if I keep her under about 73MPH, did 400 Mile round trip last weekend and got 22.1 on the way there, and 21.4 on the way home.

Anyway, I am not saying you are wrong, just more curious on what characteristics of the DFM in your vehicle make your driving experience poor. In my rig, I set the cruise and life is grand, if I need power, I hit the gas, and there is immediate downshift and the 6.2 comes to life and I am off to the races. In town, I never notice it engaging or disengaging...I'm at 30.5k on the odometer, and things are still smooth as silk. That said, my rig is 100% stock on everything engine/exhaust related.

EDIT: I just re-read the whole thread, see your complaint is primarily shudder/vibration at cruise or gentle throttle application (presumably not enough power demand to reactivate all cylinders?)
Is it possible you actually have the transmission shudder issue, and it is just more noticable when DFM is enabled, vs DFM? Do you have the 5.3 or 6.2? That coule be another factor, as could be your performance exhaust?
All good, seems disabling it helped your application...glad there is a solution that works for you.

Mike - this is exactly what I would say about my 2024 Chevy Tahoe 6.2l. Except I am only around 6k on odometer. After reading a lot of posts here I really started listening with radio off and windows down. I never hear anything related to DFM or feel any shutter or anything different in the ride.

It’s got me frustrated as I was considering getting exhaust upgraded as the engine is way too quiet unless I am back but the tailpipes. The 6.2l sounds beautiful but way too quiet. I am afraid of changing exhaust and hearing or feeling the DFM!

 

[RG23RST]

Please note: I don't own one of these direct injection engines with the 'How Many Cylinders Now?' bug/feature.
That said ...
There are two situations during which I see MINIMAL harm in this feature being active:
1. 0% throttle decelerations (aka Decel Fuel Cut Off / DFCO)
2. Whenever the engine coolant temp has exceeded somewhere between 221F / 105C & 230F / 110C
(I'm using that coolant temp threshold as a proxy for being in danger of overheating)

1. While you happen to be decelerating @ 0% TPS, you don't need ANY cylinders,
the road is effectively turning the wheels, which are turning the axles, which are turning the transmission, which is turning the engine,
because no cylinders are receiving ANY fuel anyway - so it's kind of a moot point.

2. It should be a well-known fact that Chrysler's earliest attempts at Engine Half@$$ allowed the 4 lazy cylinders to get so cold,
they cracked engine blocks.
IFF the engine is in danger of overheating, running on the minimum number of cylinders needed and varying them moment-to-moment
may help to keep engine temps down in all 8 cylinder sleeves, or at least delay overheating by a minute or two, which may be very helpful

Under the vast majority of normal driving circumstances, however,
there is NO REASON to have Cylinder Confusion enabled *except possibly for the two caveats above*.Actually he does NOT.
The way On/Off lifters work, is when the cylinder goes lazy / Off, oil flow is DENIED to that cylinder's lifters.
So when the engine is in V8 mode, oil is pumping those lifters up, same as it's worked since hydraulic lifters first started replacing solid lifters.

On / Off lifters will last longest if they are always ON / if Cylinder Confusion is disabled.

Please don't post misinformation. The lifters are de-activated via oil pressure directed from the oil control solenoids. Oil pressure is not reduced to the hydraulic lash adjusting portion of the lifter during this operation. In reality the lifters see more lubricating oil during DFM operation. In normal use the solenoids will pulse oil through these passages to keep them clean and eliminate any air pockets that could impact switching time. I'm not sure if the Range device allows this to still occur so there could be some concern with the small passages getting clogged but I don't think its much issue as long as your change your oil.

 

[RG23RST]

Mike - this is exactly what I would say about my 2024 Chevy Tahoe 6.2l. Except I am only around 6k on odometer. After reading a lot of posts here I really started listening with radio off and windows down. I never hear anything related to DFM or feel any shutter or anything different in the ride.

It’s got me frustrated as I was considering getting exhaust upgraded as the engine is way too quiet unless I am back but the tailpipes. The 6.2l sounds beautiful but way too quiet. I am afraid of changing exhaust and hearing or feeling the DFM!

You're more likely to hear and feel vibrations from the DFM once you get more miles on the rig. 10-20 thousand miles and the springs on the exhaust valve (or valves if you have a 6.2) get a little weaker and the valves can flutter meaning more unwanted vibrations working their way into the cab.

 

[tagexpcom]

I have a 2021 Yukon with 6.2L and 55K miles - bought used 1 year ago.

It idles with a pleasing purr/rumble and haven't noticed any noises/vibrations/power-issues while driving except...

When coming to a full stop, the engine seems to sputter a bit (like it' needs a tune-up / going to die) and then it revs up just a bit to idle smoothly. Not sure if this is DFM or auto-stop feature related. I have the auto-stop = off via that after market unit I installed.

 

[iamlegion]

I have a 2021 Yukon with 6.2L and 55K miles - bought used 1 year ago.

It idles with a pleasing purr/rumble and haven't noticed any noises/vibrations/power-issues while driving except...

When coming to a full stop, the engine seems to sputter a bit (like it' needs a tune-up / going to die) and then it revs up just a bit to idle smoothly. Not sure if this is DFM or auto-stop feature related. I have the auto-stop = off via that after market unit I installed.

It’s adjusting timing (torque management) to protect the transmission. Does it remotely effect driving the vehicle or just a nuance you notice?

 

[tagexpcom]

It’s adjusting timing (torque management) to protect the transmission. Does it remotely effect driving the vehicle or just a nuance you notice?

Just a nuance as it only occurs immediately after a full (hard) stop for 1-2sec till smooth idle. Would have to stop, and then immediately punch it within 1sec to see if it had any affect on mobility and haven't tried that.

 

[jerry455]

I have a 21 Suburban with a 6.2 and 76,000 miles, I hardly notice any noise and everything operates seemlessly. I am only interested in eliminating DFM because I plan to keep this vehicle for a very long time. I have only had it for 4 months now but I love it. I would like to make the sound a little louder but I don't want to get in that drone range while towing our travel trailer. Years ago I had a giant Walker Dynomax muffler, single 3" in and 3" out and over 30" long, that was a little louder but not noisy. I might try one of those again.