DFM disabler released

[Marky Dissod]

The problem with pumping air during DFCO is the cat gets too cool.

Cylinder itself also gets cooled down pretty quickly.
From its inception, DFCO has had several exclusion parameters to prevent it from excessively cooling
both the cylinder AND the catalytic converters, which became more sophisticated as time went on.

So they have to fuel and fire cylinders or go into DCCO operation which doesn't pump air.

Engine Half@$$' major weakness (even in the hypothetical world where the 2mode lifters are as robust as their 1mode ancestors)
is that 2 out of 4 cylinders on each bank could get much colder than the other 2 that never take any breaks.
Earliest versions of Chrysler Hemi's Multi-Displacement System, trying to eke out a few more MpG,
literally cleaved engine blocks when the part-time cylinders were too cold compared to the full-time cylinders,
before properly limiting how long the engine could stay Half@$$ed while remaining intact.
(Trying to save too much gas is risking the engine's @$$!)
Point is, firing cylinders stay warmer longer than air spring cylinders (DCC), air spring cylinders stay warmer longer than DFCO cylinders.

My GUESS:
Engine is at operating temp. You take your foot off the go-pedal.
Aero shutters close to divert air around the radiator, keeping things warm longer.
Tula skip fire (and thus Dynamic Fuel Management) avoids cracking the engine block by never letting any one cylinder cool off too much.
Some cylinders firing, some cylinders in DCC, some cylinders in DFCO,
change 'em up often enough that each cylinder maintains as much heat as long as possible,
and each cylinder's temp stays as close as possible to every other cylinder's temps.

In certain situations I'd bet the ecm & tcm might even collude to effectively go into Neutral
while simply idling the engine during some decelerations, if the engine and or cats are getting too cold.

 

[Scarey]

Too bad Range and Carbyte don’t speak up on this forum to help us the user make an informed decision. I’m not so sure I’m going to continue to experiment on my $85k suv if they aren’t willing to speak up.

 

[Marky Dissod]

I’m not so sure I’m going to continue to experiment on my $85k suv if they aren’t willing to speak up.

They're saving unpaid time and energy by pleading the 5th.
Still, the less time the lifters spend 'deactivated', the longer they tend to last.
It's still be worth it to deactivate them as much as possible, even if that's no longer 'always' like it used to be.

This is not to excuse deceptive advertising.

 

[DontTaseMeBro]

A question of those who have the Carbyte. Does the app show when DFM is disabled real time? Cause I really want to know if it’s working. As mentioned before, prior to installing mine, I could not tell when DFM would kick on in my 2022 Yukon w/6.2 leading me to wonder if it was disabled from the factory(window sticker makes no mention)?

Anyone?

 

[Scarey]

I’m no expert on the carbyte but my experience is the app is spotty. When paired it does not always respond to my request to turn off Dfm disablement or auto stop. The way I’ve seen it work is the carbyte device works as advertised when you plug it in, don’t need the app. The app really does not show Dfm on or off. You can request to turn disablement off but my experience is it doesn’t always respond. If when I use the module I just plug in obd port and don’t use app. I can see it working by the mpg doing what would be expected, not wild swings in mpg when Dfm operating. Definitely notice when coast is disabled because it doesn’t slow nearly as quick and mpgs don’t show 99.

Ps I’m not using either because neither carbyte or range will speak publicly about questions that have been raised on the forums. I stoped being a beta tester with a $85k truck. Good luck all.

 

[djnice]

Its interesting people say the carbyte coasts faster with less engine braking. My stock vehicle coasts like any I have ever had. Engine braking and downshifting. The carbyte having less engine braking sounds like a problem or something i wouldn't want.

 

[Marky Dissod]

... having less engine braking sounds like a problem, or something i wouldn't want.

I STRONGLY suspect I'll never own a new vehicle. Except for my Z71, every vehicle I've ever owned has been a '94 or '95.
The previous was context for the following:
When I select neutral on flat road, I expect barely detectable deceleration once I'm under about 60MpH (aero drag increases quickly over 65MpH).
If I stay in 'D' and lift off the go-pedal, I expect SLIGHTLY more decel than if I select neutral on flat road,
if only because the transmission is connected to the engine, and there's gonna be a wee bit o' engine drag.
If it's not in the highest possible gear, it's not just engine braking, it's also powertrain braking.

If the trans is connected to the engine, but the DFM engine is in both DFCO AND 0-cylinder mode during a coasting down,
is that closer to neutral, or closer to DFCO?

 

[djnice]

The stock vehicle does not coast like in neutral. It has drag and engine braking like every auto I have ever had. I have had a bunch of Chevy trucks ranging from 69 to 06.

 

[23Seven]

L9 = Engine Braking when I lift off the go pedal. It’s already a habit for me to hit drive and then L ++++++++ when going for a drive. Engine stays a V8 and comes to a stop just like my 03 Silverado 5.3 did.

Range caused an engine light and was put back in the box and sent back to Holley.

 

[allenaa25]

I'm running the Carbyte on my 25 Denali 6.2 and does drive noticeably better. I did notice it feels like it's in manual mode when decel/zero throttle and MPG doesn't go to 99 like when not running the carbyte, also it doesn't seem the app controls functions like it should but still think it's worth what it cost. I'm installing the Range this weekend to see the difference. Personally I'd prefer the zero cylinder decel function, does seem to make a big difference in fuel mileage and want the engine breaking function for towing. In my comparison, does seem Range is probably accurate on making a big difference in fuel mileage. If you run the carbyte I would recommend running it without using the app. I've had auto stop work when app says it's not active. But no issues when no using the app.

 

[jfoj]

Update on the Range module, finally had a chance to get a more advanced scan tool on the truck today. During Decel with Fuel Cut Off (DFCO) the ECU did show cylinder deactivation. I could watch the incremental counters for each cylinder increase during DFCO and the instantaneous Fuel Economy at 99 MPG.

While I might prefer the DFM be 100% disabled all the time, having it only active during DFCO is better than nothing. Overall if seems that is clearly exercises the lifters far less than if the DFM was always active. Additionally some activity to flush and exercise the lifters may not be a bad thing??

Anyway, I have to next test and monitor with the transmission in 9th gear to see what happens during DFCO. I would not likely drive at full highway speeds with the transmission in 9th gear for many reasons.

The one thing that is annoying about the Range device is it will not allow all the OBDII Readiness Monitors to set, this may be the way they disable the DFM? So this means the Range device will need to be removed prior to any state Emission Inspections to allow all the Emission Readiness Monitors to be set, then it would need to be reinstalled again.

Just a bit more effort, but overall this still seems worth it in the long run.

 

[Marky Dissod]

I have to next test and monitor with the transmission in 9th gear to see what happens during DFCO.
I would not likely drive at full highway speeds with the transmission in 9th gear for many reasons.

FYI, 10L80's 9th gear is basically 4L60's 4th gear.
When the engine load in 10th gear gets too high, it would just downshift to 9th / 4L60E's 4th.

I can only think of 1 reason to avoid 10th altogether:
if an overrun clutch is applied in 9th. Otherwise it should be all good.

 

[Scarey]

Very cool. I think that is what allot of us suspected. I agree you may want oil occasionally to cycle through the lifters. Not getting cooked and gumming up. Would be very interested in seeing what your L9 dfco results are. Thanks for putting the effort in.

Ps. I’m curious if there is various stages of dfco. In steady state cruise and lightly letting off the gas, maybe throttle closes and fuel starvation. Vs rapidly letting of the gas and going into full cylinder deactivation to gain the additional engine deceleration?

PSs last thought. I wonder if there could be any connection with the bearing failures on the 6.2s, maybe low engine oil pressure caused by dfco?

 

[RG23RST]

You need to watch the actual current to the solenoids, not what the ECM is commanding. Remember the Range device sits on the “output” side of the ECM. With the Infineon SOC they use it’s pretty obvious what’s happening.

 

[RG23RST]

Very cool. I think that is what allot of us suspected. I agree you may want oil occasionally to cycle through the lifters. Not getting cooked and gumming up. Would be very interested in seeing what your L9 dfco results are. Thanks for putting the effort in.

Ps. I’m curious if there is various stages of dfco. In steady state cruise and lightly letting off the gas, maybe throttle closes and fuel starvation. Vs rapidly letting of the gas and going into full cylinder deactivation to gain the additional engine deceleration?

PSs last thought. I wonder if there could be any connection with the bearing failures on the 6.2s, maybe low engine oil pressure caused by dfco?

The answer to all your guesses is no. GM has used an advanced neural network/AI algorithm in the engine controller since this generation debuted in 2018. What this allows is very low latency calculations to occur based on sensor data to efficiently determine the best firing fraction, fuel trim, ignition timing, throttle valve position, charging state, commanded oil pressure and so on. Its partly why tuning them is a nightmare that involves re-training this neural network.

The 6.2 bearing issues are a supplier quality concern is my understanding. They don’t have “low” oil pressure unless the pump is malfunctioning somehow. Engineers figured out a long time ago volume, not necessarily pressure, is best. It’s the film strength of the oil keeping metal parts from French kissing, not the PSI of the oiling circuit forcing them apart.

 

[ninjaplumber]

Update on the Range module, finally had a chance to get a more advanced scan tool on the truck today. During Decel with Fuel Cut Off (DFCO) the ECU did show cylinder deactivation. I could watch the incremental counters for each cylinder increase during DFCO and the instantaneous Fuel Economy at 99 MPG.

While I might prefer the DFM be 100% disabled all the time, having it only active during DFCO is better than nothing. Overall if seems that is clearly exercises the lifters far less than if the DFM was always active. Additionally some activity to flush and exercise the lifters may not be a bad thing??

Anyway, I have to next test and monitor with the transmission in 9th gear to see what happens during DFCO. I would not likely drive at full highway speeds with the transmission in 9th gear for many reasons.

The one thing that is annoying about the Range device is it will not allow all the OBDII Readiness Monitors to set, this may be the way they disable the DFM? So this means the Range device will need to be removed prior to any state Emission Inspections to allow all the Emission Readiness Monitors to be set, then it would need to be reinstalled again.

Just a bit more effort, but overall this still seems worth it in the long run.

I am going to have to respectfully disagree with the range device needing to be disconnected. I installed the range device in my 2021 Escalade Sport on 10/5/2024. Went for an inspection about 1 1/2 months later and all the OBD monitors that are available were labeled ready and passed. I do know that some of those monitors take a while to set after you mess with things.

 

[ninjaplumber]

 

[jfoj]

I am going to have to respectfully disagree with the range device needing to be disconnected. I installed the range device in my 2021 Escalade Sport on 10/5/2024. Went for an inspection about 1 1/2 months later and all the OBD monitors that are available were labeled ready and passed. I do know that some of those monitors take a while to set after you mess with things.

ninjaplumber,

You get a pretty good deal on Safety and Emission inspections in MA, in VA the cost is $50 for both! But I am sure MA gets it out of you other places.

I have a vague recolection when I was looking for a used Yukon Denali, I was originally looking at the 2021 and 2022 model years. I seem to recall that when I first looked at the Range devices they had some support for them, but when I opened my search up to the 2023 and 2024 they did not have a solution at the time. This was back in mid 2024 so my memory may be wrong? Additional I recall something slightly different about the 2021 models carry over from 2020 or may being build in and around the chip shortages something unusual was happeneing to some builds. So there may be some variation on behavior depending on build dates?

I have since put many more miles and run cycles on the vehicle since I installed the Range device and at least with 1 of my tools it shows the O2 Sensors have actually passed, but the Evap is still not in a ready state. I will check with a number of other tools I have to see if this is in fact consistent and correct on all of my tools.

Now the issue of the Evap Monitor not showing as ready will pass in some states, but not it all states as I recall. This is partially due to the Evap Monitor being one of the more difficult Readiness Monitors to become Ready. While the Evap Monitor may not be Ready, as long as there is not a Pending or Permanent trouble code for the Evap system, again, some states will all the vehicle to pass a State Emission Test.

Below is an excerpt from a message I sent to Range Techology Support regarding this issue along with their reply to my question.

"Hello,

Recently purchased a RA007 for my 2024 GMC Yukon Denali XL with the 6.2L gasoline engine.

Installed the module, but have not driven the vehicle more than about 100 miles since installing the module.

A bit concerned as when checking the Emission Readiness Monitors, the Evap and O2 sensors are not complete yet. I understand the Evap Readiness Monitor is often one of the most difficult to set, but a bit concerned the O2 sensors have not set yet. The O2 sensor heaters have set, but not the O2 sensors themselves.

Have you tracked the Emission Readiness Monitors and have you seen any issue with this RA007 causing certain Readiness Monitors not to complete or take longer to complete?

Please advise,

Regards,"

Here was the reply from Range Technology Support

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

Thank you,

Customer Support

866-404-6141

Range | SuperChips | DiabloSport | Edge

 

[ninjaplumber]

You may be correct. I really don't know if there were any changes to those procedures. I do know those procedures can be difficult to meet and could take a while. I had a Evap monitor issue on my 2017 after I unplugged the range OBD unit. The attachment was written by Range in 2019 I believe.

 

[nick14226]

ninjaplumber,

You get a pretty good deal on Safety and Emission inspections in MA, in VA the cost is $50 for both! But I am sure MA gets it out of you other places.

I have a vague recolection when I was looking for a used Yukon Denali, I was originally looking at the 2021 and 2022 model years. I seem to recall that when I first looked at the Range devices they had some support for them, but when I opened my search up to the 2023 and 2024 they did not have a solution at the time. This was back in mid 2024 so my memory may be wrong? Additional I recall something slightly different about the 2021 models carry over from 2020 or may being build in and around the chip shortages something unusual was happeneing to some builds. So there may be some variation on behavior depending on build dates?

I have since put many more miles and run cycles on the vehicle since I installed the Range device and at least with 1 of my tools it shows the O2 Sensors have actually passed, but the Evap is still not in a ready state. I will check with a number of other tools I have to see if this is in fact consistent and correct on all of my tools.

Now the issue of the Evap Monitor not showing as ready will pass in some states, but not it all states as I recall. This is partially due to the Evap Monitor being one of the more difficult Readiness Monitors to become Ready. While the Evap Monitor may not be Ready, as long as there is not a Pending or Permanent trouble code for the Evap system, again, some states will all the vehicle to pass a State Emission Test.

Below is an excerpt from a message I sent to Range Techology Support regarding this issue along with their reply to my question.

"Hello,

Recently purchased a RA007 for my 2024 GMC Yukon Denali XL with the 6.2L gasoline engine.

Installed the module, but have not driven the vehicle more than about 100 miles since installing the module.

A bit concerned as when checking the Emission Readiness Monitors, the Evap and O2 sensors are not complete yet. I understand the Evap Readiness Monitor is often one of the most difficult to set, but a bit concerned the O2 sensors have not set yet. The O2 sensor heaters have set, but not the O2 sensors themselves.

Have you tracked the Emission Readiness Monitors and have you seen any issue with this RA007 causing certain Readiness Monitors not to complete or take longer to complete?

Please advise,

Regards,"

Here was the reply from Range Technology Support

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

Thank you,

Customer Support

866-404-6141

Range | SuperChips | DiabloSport | Edge

The device came out to support 21-up in Fall 2024, wasn’t one before that supporting 21-22 only.

You guys got me curious so hooked up the OBD reader. Looks like my ‘22 5.3 is like @ninjaplumber, readiness monitors are set. Was assuming I’d have to pull it for NY inspection based on other posts, but looks like I’ll be ok.