DFM disable

TXGREEK · February 17, 2020

I'm just fine and dandy with DFM
Thos is with 89 octane
I might possible could've squeezed 600 miles out of a tank! That's incredible compared to 375 miles as before on my 07 Classic, that got a damn respectable 17/19

I was too until I found a striking comparison that every vehicle that’s had issues was running with no cylinder deactivation tune.

Btw, did my Amsoil OCI today, I was shocked to find my oil pressure was much higher than when I was running OEM and Wix XP oil filters.

With Wix filters oil pressure was much lower at idle, this pic is of the Amsoil 25k mile oil filter, excellent oil pressure flow

Sent from Above

Dallas Kiezik · January 1, 2021

On 2/13/2020 at 6:18 AM, Thomcat said:

According to the chart in the first link Corvettes use AFM, not DFM. And as for the 8 speed of a few years ago running that hydroscopic Dextron that screwed with interior components ....yes.... problems, but not necessarily caused by AFM , certainly impossible by DFM, and not shared with later trannys running the new Mobil1 HP fluid from the beginning, or 100% changed soon after operation before it could cause an irreversible effect on tranny operation. That's purposely why I bought a post 3/19 production 8 speed....to assure it came from the factory with a belly full of Mobil 1 Synthetic LV ATF HP! And no engine vibration orshudder in my tranny running that combo. So, no need to be a guinea pig trying one out on a new advanced system with different operations and processors.

If you're talking AFM, yes, they're crap no matter what you throw them in....they've been kludging them since my '07 Avalanche...and the driver (not just the tranny) can feel the AFM kick in .. ..oil ring clogging, wearing and turning into oil burners and a POS valve cover that sucks oil from the upper end and dumps in the induction system, that's why you need a catch can......nasty harmonic for the same 4 dead cylinders at a specific speed, etc. Numerous TSB modifications including 3 versions of revised valve covers, two for shielding of the AFM discharge valve in the sump and numerous design revisions to the collapsible valve lifters....all around an engine designed for potential problems from the start with the same 4 of the 8 cylinders operating dead yet still pulling oil onto their colder cylinder walls overloaded with oil spray from the AFM discharge valve in the sump. I always used the range device AFM defeat device on long trips because continued operation with the same four dead, colder cylinders cruising on a long trip for a prolonged period wasn't good.

Couldn't wait to dump the fully kludged up '16 AFM in favor of the completely redesigned DFM arrangement eliminating the OLM altogether, new domed valve cover w/oil straining baffles to eliminate the need for a catch can, no more oil ring clogging AFM discharge valve in the sump, rotation of dead cylinder patterns to even out cylinder temperatures and not generate the same frequency vibration harmonic each time in operation. Actual performance of the same size DFM vs. AFM is remarkable..... control of the complex system required development of an advance processor to always keep the engine at full time peak performance. Seems GM finally relegated the AFMs to the retirement home, using up all old stock and you won't be seeing them on newer production vehicles.

Doesn't take an engineering degree to review the docs and realize DFM is a whole different animal without the same AFM flaws.

https://gm-techlink.com/?p=11880

https://gmauthority.com/blog/gm/general-motors-technology/general-motors-propulsion-technology/general-motors-dynamic-fuel-management-cylinder-deactivation-technology/

https://gm-techlink.com/?p=11127

Well perhaps you should see what my catch can collects on this new motor. The low sodium to be dexos approved is fine, but the low shear stability that vaporizes the 0w20 oil is still a problem. A 5w20 maybe the way to go if the cold pumping viscosity is very similar and still dexos approved

PSUFAN · January 3, 2021

So at the end of the day, should I keep the Range DFM disabler I bought and put in my 2020 Silverado LT or do I not need it? I'm not mechanically inclined so I rely on the experts on this board to provide me insight and opinions.

SPASierra · January 4, 2021

On 1/3/2021 at 1:20 AM, PSUFAN said:

So at the end of the day, should I keep the Range DFM disabler I bought and put in my 2020 Silverado LT or do I not need it? I'm not mechanically inclined so I rely on the experts on this board to provide me insight and opinions.

That is a complete judgement call. I don't think anyone buys the Range to gain MPG. They buy it so they have a full V8 all of the time, not part of the time. That is why I bought mine. For longer road trips, where you really want the MPG savings while cruising at highway speeds, unplug it and toss it in the center console. That is what I do with mine.

Luckyfd · January 25, 2021

On 2/13/2020 at 5:07 PM, snork said:

nice thing about the C7 corvette is you can deactivate the dfm by selecting sport or track mode

I’m confused why you can’t turn the off the DFM by setting the Silverado in sport or tow mode...I’m not positive putting the truck in L7 shuts it off either.

Edited January 25, 2021 by Luckyfd

RWTJR · January 25, 2021

1 hour ago, Luckyfd said:

I’m confused why you can’t turn the off the DFM by setting the Silverado in sport or tow mode...

Let me see if I can help clear up the confusion.

GM designed and built the SIlverado, Seirra and other vehicles so that the DFM could not be turned off by placing the vehicle in Sport or Tow mode. Therefore, you can't turn it off by putting in Sport or Tow mode.

I hope this helped.

JMHO

No expertise i plied or expressed

Luckyfd · January 26, 2021

18 hours ago, RWTJR said:

Let me see if I can help clear up the confusion.

GM designed and built the SIlverado, Seirra and other vehicles so that the DFM could not be turned off by placing the vehicle in Sport or Tow mode. Therefore, you can't turn it off by putting in Sport or Tow mode.

I hope this helped.

JMHO

No expertise i plied or expressed

Lol that was the most concise answer ever, thanks.

TexasBB · January 26, 2021

I bought my range the first couple of months they were available and have used it ever since. Most days it works great, but 3-4 times a month the engine will still stop. It makes me wonder if the dfm is actually disabled as there is no indicator and I don’t have duals. Does anyone know if there’s a way you can tell if the dfm is disabled?

Sent from my iPhone using Tapatalk

Transient · January 30, 2021

I bought my range the first couple of months they were available and have used it ever since. Most days it works great, but 3-4 times a month the engine will still stop. It makes me wonder if the dfm is actually disabled as there is no indicator and I don’t have duals. Does anyone know if there’s a way you can tell if the dfm is disabled?

Sent from my iPhone using Tapatalk

Just a guess, but looking at the fuel economy numbers might help

Sent from my SM-N960U using Tapatalk

Krom · December 25, 2021

On 2/12/2020 at 5:20 PM, Thomcat said:

Why would I disable something that I can't even notice in operation anyway? Besides gizmo has to be temporarily removed for inspection or servicing restoring DFM function.

These engines no longer use an OLM like the previous AFM version, DFM uses block mounted oil control solenoids for each cylinder which are constantly cycling. Doesn't seem to be any long term studies on the effects of keeping the oil control solenoids or collapsible lifters static for a long period of time and then reactivating for inspection or service.........and I have no desire to be the guinea pig that finds out.

Does anyone have info on completely removing the hardware for DFM?

85,000 miles and the lifters ate the cam on my BIL's 2019, GM says to pound sand, dealer wants almost 10 grand to replace the cam and 16 lifters

Edited December 25, 2021 by Krom

Supreme Pizza · December 26, 2021

10K hahaha. The dealership is such a scam.

Anyway, the complete delete usually involves replacing the cam, lifters, oil pump, and various other parts.

In your situation, I would probably replace the motor, and reprogram the computer to disable the DOD/AFM/DFM.

Here are a few links, to give you an idea of what the options are:

https://sdparts.com/i-24138746-sdpc-l83-dod-afm-delete-kit-for-2014-2018-gen-v-5-3-engines.html

https://www.ebay.com/itm/133572585048?hash=item1f198be658:g:Di8AAOSw0axfqrnF

https://www.amazon.com/Qzucar-Active-Management-Disable-Device/dp/B08LL8BB8G/ref=sr_1_13?crid=2JYVGTRS66P95&keywords=afm+disabler&qid=1640480642&sprefix=afm+disabl%2Caps%2C221&sr=8-13

dgstarr63 · December 28, 2021

I agree that the DFM is a much better design than the AFM, but we are still seeing lifter failures on new trucks. When my 2021 5.3 with DFM turns 8000 miles, I will plug in the Range. I don't think this is a 100% effective way to stop lifter failure, but I can't believe that disabling the collapsing of the lifters will not slow down the failure rate.