So Tell Us About Dynamic Fuel Management in Your 2019 T1's

Wiggums · April 22, 2019

I'm still waiting for somebody to deactivate DFM and report the results....

JR09country · April 26, 2019

From Dallas to Houston, running anywhere between 70 and 75. Very happy with these results.

Lt trail boss

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KARNUT · April 27, 2019

When I had my 2014 and was posting on the mileage thread I would show mileage between 200-400 miles. These 25-50 miles postings don’t mean much. I got 23 mpg at 72 mph for a full tank on the interstate. It’s probably still posted on this web site the summer of 2014, with the cylinder deactivation turned off.

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TruckerTom · April 27, 2019

On 2019-02-14 at 1:21 PM, Sierra Dan said:

So I am interested in what you 2019 T1 owners have to say about the Dynamic Skip Fire or Dynamic Fuel Management operation in your new trucks.

Especially those of you who have moved from an AFM on K2.

Do you notice the new system benefiting MPG?

Can you feel the engine switching around?

Is it more seamless compared to AFM?

Any negative transmission shifting from time to time either 8 or 10 speed?

The big difference is that there is no longer the V8 V4 red green indicator on the instrument cluster.

That said, do you even notice when the switching takes place?

I have 6.2 litre 2019 Denali with the DFM I am amazed at the fuel milage. 21 MPG (US gallons) highway.. 17mpg City,. Way better than my 5.3 This was from day 1 ..which is usually worse before the break in.

The switch between cylinders is flawless. The engine shuts down when you come to a stop or in traffic. (option to turn off) Can't tell unless your listen very intently . I was a bit disappointed in the pulling power. You have to keep it below 60 mph (100kms for us Canadians) to maintain 1800 rpms . 2-5 mph over goes to 3500 rpms every time.

econometrics · April 27, 2019

Just got 23mpg with my 5.3L DFM on a longer trip home tonight. Going 65-70mph.

DougFL · May 30, 2019

Just took a recent trip from FL to MD. Mostly Highway ~ 7 over limit, except for almost an hour of stop and go around the VA/MD boarder! Still doing well after 20K miles.

FDHog · May 30, 2019

I have a 19 AT4 with 6.2L. Was a little leery coming from an F150 to the GM DFM system. So far, I don't even notice it. When I hit the gas, it responds quickly. The Catback doesn't sound any different as far as I can tell. Very happy so far. Hopefully this system has some longevity. If I keep the truck past 3 yrs, I'll go for the extended warranty for peace of mind.

ndking1126 · May 31, 2019

I have a 5.3 LT with about 450 miles on it. Gas mileage on the first take with mixed driving was 19.7 and I'm very happy with that. I have the slight shake/roughness of the engine at low throttle from about 45-60 mph, though, and it annoys me. To me it feels like whatever DFM mode it is in at the moment is just too aggressive in trying to save fuel. Kind of reminds me when you're driving a standard and you pick 5th gear and you should have gone into 4th and the engine is just trying to stay running. I don't want all of DFM deactivated because otherwise it's perfectly seamless, but maybe if they could remove that one DFM mode and have it pick a mode that would provide more power, it would be perfect.

Edited May 31, 2019 by ndking1126

DougFL · May 31, 2019

13 minutes ago, ndking1126 said:

I have a 5.3 LT with about 450 miles on it. Gas mileage on the first take with mixed driving was 19.7 and I'm very happy with that. I have the slight shake/roughness of the engine at low throttle from about 45-60 mph, though, and it annoys me. To me it feels like whatever DFM mode it is in at the moment is just too aggressive in trying to save fuel. Kind of reminds me when your driving a standard and you pick 5th gear and you should have gone into 4th and the engine is just trying to stay running. I don't want all of DFM deactivated because otherwise it's perfectly seamless, but maybe if they could remove that one DFM mode and have it pick a mode that would provide more power, it would be perfect.

I do not have that problem. Try setting the Truck in Sport mode and see if that makes a difference.

Wiggums · May 31, 2019

I got 28.8 MPG out of mine... 5.3 V8 4x4 Crew Cab going 55-60 mph on a somewhat flat surface.

ndking1126 · May 31, 2019

Quote

I do not have that problem. Try setting the Truck in Sport mode and see if that makes a difference.

That was my plan, just haven't yet. I've been trying to research if sport mode changes how DFM works, and nothing I've read says it does. In theory it could keep DFM from going into that specific mode so it's worth a shot.

ndking1126 · June 1, 2019

12 hours ago, DougFL said:

I do not have that problem. Try setting the Truck in Sport mode and see if that makes a difference.

Wouldn't you know on the way home today it worked perfectly. At one point I was going up hill at 1100 rpm at about 45 or so and it crawled right up. It doesnt do it everytime. I put it in sport mode just because and it down shifted. RPMs would be high enough it wouldn't happen either way.

Wiggums · June 1, 2019

A part of me wishes the DFM activation was more aggressive since I am not lead footed.

It would be nice if somebody could tune my chip to lower the power. We all did fine when the 5.0 V8 engine had only 130 hp back in 1983. Now, it's 355. Hell, I'd be happy with 150 hp if I could get 40 mpg out of it!

My old man had a 1982 F-250 with the huge 400 V8 that pumped out only 153 hp! He was da shit on the block back in them old days.

Moend · June 1, 2019

13 hours ago, Wiggums said:

I got 28.8 MPG out of mine... 5.3 V8 4x4 Crew Cab going 55-60 mph on a somewhat flat surface.

That is nice. The best I got so far is 21.3

Moend · June 1, 2019

7 minutes ago, Wiggums said:

A part of me wishes the DFM activation was more aggressive since I am not lead footed.

It would be nice if somebody could tune my chip to lower the power. We all did fine when the 5.0 V8 engine had only 130 hp back in 1983. Now, it's 355. Hell, I'd be happy with 150 hp if I could get 40 mpg out of it!

My old man had a 1982 F-250 with the huge 400 V8 that pumped out only 153 hp! He was da shit on the block back in them old days.

That is funny and true. And honestly the main thing that is hurting fuel economy is emissions. And like you said some of us don't need the power all the time. It is just nice to have when needed..