2021 Silverado 6.2 Liter with 10-Speed-DFM Disabling

Ptman · April 14, 2022

I’ve seen a few posts regarding deactivating the Dynamic Fuel Management system on the new models with 10-speed transmission. Apparently there is no inexpensive plug-in option with the exception of the PULSAR LT FOR 2019-2022 GM 1500 5.3L/6.2L. That unit sells for $500+ and is capable of controlling more than the DFM system. I’m looking for a simple plug-in unit similar to the Pulsar unit. Is anyone familiar with anything or know if Pulsar is working on a unit that is compatible with the newer 10-speed transmissions?

Edited April 14, 2022 by Ptman

f8l vnm · April 14, 2022

Can you please explain why you want to disable it ? And i mean that with no disrespect , just curious .

Ptman · April 14, 2022

There’s more cons that pros. It’s not something I thought of on a whim. I don’t like the way it feels and sounds and prefer to have all 8, all the time.
One argument is that the engineers designed it that way so don’t modify it but engineers also designed the Boeing 737 Max. Engineers are not infallible and I believe it’s better to override it.
So can you answer my question?

Jay P · April 14, 2022

If you put the transmission in M9 DFM will not be active. The range DFM disabler is hit/miss (10 speed only). It works for some and doesn't work for others. Don't know of any other options other than the Pulsar you mentioned.

Jay

Edited April 14, 2022 by Jay P

todd308 · April 16, 2022

On 4/14/2022 at 2:16 PM, Jay P said:

If you put the transmission in M9 DFM will not be active. The range DFM disabler is hit/miss (10 speed only). It works for some and doesn't work for others. Don't know of any other options other than the Pulsar you mentioned.

Jay

I've wondered if this is really true and this is why. When I run my AT4 in L-9 (or M-9) you are right it drops the instant fuel economy down from just being in Drive, coasting down the same hill everyday driving to work is an easy way to check. However, I've wondered if it's doing something in the middle (for example letting DFM shut down up to 4 cyl but not all 7. The reason I say this is because when I run the Pulsar, the instantaneous mileage is even lower than it is in L-9. This leads me to believe that L-9 might be doing something "in between" what having all 8 engaged all the time does and full DFM.

Unfortunately it won't save the lifters, the problem there is the lifter integrity itself, not a result of DFM.

It's amazing what these engineers (probably forced by company bean counters) will sacrifice to get a bit of MPG on the window sticker. It's why we have front bumpers that barely clear a curb, why we have DFM and self destructing lifters, front end rake so the truck looks like a door wedge from the side, and tiny fuel tanks. There's a video talking with the head Tunda designer for the new Hybrid tundra. They used to have a 38gal tank, and their goal was to be able to drive 4 hours towing at max capacity. When they got the hybrid they gained MPG so they shank the gas tank 6 gallons and he even states they did it to save weight to gain MPG.

That's right a whole team of truck engineers thought it was a better idea to save 50 lbs of fuel on a 5500lb truck to gain some tiny fraction of MPG rating, than give the driver 20% more driving range.

Edited April 16, 2022 by todd308

Jay P · April 16, 2022

I had an issue with the Pulsar on my 19 GMC. If you look at instant fuel economy with it attached you will notice it never gets to 99mpg like it does without the Pulsar when coasting. I think it's not allowing the injectors to cut fuel when coasting and that why mileage drops. When I had the Range DFM disabler installed the milage didn't drop at all.

Jay

todd308 · April 17, 2022

1 hour ago, Jay P said:

I had an issue with the Pulsar on my 19 GMC. If you look at instant fuel economy with it attached you will notice it never gets to 99mpg like it does without the Pulsar when coasting. I think it's not allowing the injectors to cut fuel when coasting and that why mileage drops. When I had the Range DFM disabler installed the milage didn't drop at all.

Jay

Yeah, basically that's what I'm seeing in my post above that led me to believe it's doing more than just L-9 is. For my 21' in L-9 it also will never get to 99 coasting downhill, it sits in the mid-upper 60's, low 70's usually, don't think I've ever seen it in the 80's, Pulsar I don't think I've ever seen get above the upper 40's. Father put a Range in his, admittedly much older 2007 6.0L and he also noticed that it cut the instant mileage while coasting, so it's interesting that it doesn't seem to impact it at all on the AT4's.

A lot of folks have reported odd phantom issues with the Pulsar. I haven't had any, but I will say that when I tried out the throttle sensitivity settings I found that the truck didn't idle nearly as smooth in settings other than "stock" and I actually felt like it had more hesitation. It definitely made the throttle more "touchy" but it would hesitate a bit more when you first stepped on the gas, set it back to stock and it would instantly improve. I had also hoped that you could do the DFM delete but keep autostop enabled, just because i get stuck in a lot of stop/go traffic so it makes a significant fuel difference for me. However it seems to be the truck won't autostop if it is in v8 mode. Even with the Pulsar set to allow autostop and it illuminated on the truck console, it will never actually shut the truck off. It won't in L-9 either so my guess is once you mess with the DFM, it will never shut off.

Edited April 17, 2022 by todd308

Big_Kahuna · April 17, 2022

on the ram trucks you can put it in 8 gear witch is final gear and truck will never engage cylinder deactivation but everything else will function normal, on the Durango that we head in 2016 was actual button on the dash to disable cylinder deactivation , I thought that that was a great thing, dodge actually give you option, I wish chevy do the same.

Rad64 · April 21, 2022

Todd308,

"That's right a whole team of truck engineers thought it was a better idea to save 50 lbs of fuel on a 5500lb truck to gain some tiny fraction of MPG rating, than give the driver 20% more driving range."

The engineers are driven by the US Government in their fuel mileage needs. CAFE standards dictate what they have to obtain for the fleet, just like in the old days when you ordered a Camaro Z28 and didn't specify high performance tires, the US Government forced GM to put a speed limiter on the car for 105 mph - tire speed rating. Just think, the new Camaro and Corvette models are being de-tuned because of the CAFE standards...