DFM disabler released

[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.