6.4l terrible mpg

2020PW · Oct 1, 2022

dhay13 said:
you can see my actual here vs my EVIC reading. usually within .7 or so MPG and even a few where my actual was better than my EVIC reading

View attachment 503001

You have too much time on your hands.

CanRebel · Oct 2, 2022

Ratman6161 said:
I really believe that those of you noticing a dramatic difference when MDS kicks on and off must have some kind of malfunction going on. I'm being totally honest here when I say that on mine, there is no perceptible shaking, vibration or noise. Either that or its min that's malfunctioning...i.e. MDS really isn't kicking in. but I don't think that's the case. When I see the green light come on, I also see an increase in the instantaneous fuel economy number.

I have 1500. I can't tell that MDS is on or off unless I look at the light. It's actually rare it does come on.

Riccochet · Oct 2, 2022

Put an aftermarket exhaust on your truck. You'll hear it clear as day when MDS kicks in and produces this god awful 4 cylinder sound. It's mostly when MDS turns off that I can feel it. Like no power, no power, no power, slight shudder aaand there we go, power!

CanRebel · Oct 2, 2022

Riccochet said:
Put an aftermarket exhaust on your truck. You'll hear it clear as day when MDS kicks in and produces this god awful 4 cylinder sound. It's mostly when MDS turns off that I can feel it. Like no power, no power, no power, slight shudder aaand there we go, power!

I have borla atak cat-back... still no difference when mds is on or off.

Spirit79 · Dec 18, 2022

I have a 2015, Oct 2014 build date, 2wd, 6.4 Crew Cab, Big Horn. Bone stock except for lighting upgrades. I live in the Southland, don’t play in mud, no need for 4wd. With my 3.73 gear I easily get 20 mpg highway. I must stay under 70 mph to get that number. (No, I don’t drone along at the speed limit all the time.) Over 70 mph there is a 2 or 3 mpg penalty minimum. I can see where lifted, leveled and especially with big aggressive tread tires could cost another couple mpg. I make weekly 250 mile trips. I almost never see modified trucks going the speed limit in the right lane. Most are the fastest traffic. I wonder if those are the people talking about abysmal mileage? You gonna play you gotta pay.

toddmakesamove · Dec 20, 2022

I drove my buddy's TRX for a week. I am convinced the transmission and 410 gears from the heavy-duty trucks are used in the TRX. My HD 3500 is the exact same stall and programming of the TRX, if you turn Tow/Haul mode on. No ECO Mode will come on with Tow/Haul on.

I'm a big gear heard. The ECO Mode seems terrible for the engine. I base this off Voodoo. I hear the terrible sounds, the shuttering, vibrations as you keep just enough gas to stay in ECO when accelerating, and I basically hate it. I keep Tow/Haul on at all times. Be careful, it changes the whole dynamic of the transmission, and it is sublime.

toddmakesamove · Dec 20, 2022

I am seeing 10 mpg all city. I'm running cheap gas at Costco. I put 47 gallons in it, the range was 539 (still had a few gallons in there), and it was under $120 (2.51 gal.). I justify it because I can pull down the side of building...stay out of my justifications. It's also on break-in - it has 400 miles on it.

Merry Christmas!

SniperDroid · Dec 20, 2022

toddmakesamove said:
I drove my buddy's TRX for a week. I am convinced the transmission and 410 gears from the heavy-duty trucks are used in the TRX. My HD 3500 is the exact same stall and programming of the TRX, if you turn Tow/Haul mode on. No ECO Mode will come on with Tow/Haul on.

I'm a big gear heard. The ECO Mode seems terrible for the engine. I base this off Voodoo. I hear the terrible sounds, the shuttering, vibrations as you keep just enough gas to stay in ECO when accelerating, and I basically hate it. I keep Tow/Haul on at all times. Be careful, it changes the whole dynamic of the transmission, and it is sublime.

Instead of using the Tow/Haul mode, try using the manual gear selector on the steering wheel. Once your in gear, tap the + side until the gear indicator on the EVIC shows 8. That sets the maximum gear position to 8th gear, and disengages the ECO mode. I use this method whenever I'm not towing.

06 Dodge · Dec 20, 2022

toddmakesamove said:
I am seeing 10 mpg all city. I'm running cheap gas at Costco. I put 47 gallons in it, the range was 539 (still had a few gallons in there), and it was under $120 (2.51 gal.). I justify it because I can pull down the side of building...stay out of my justifications. It's also on break-in - it has 400 miles on it.

Merry Christmas!

Costco gas has been known to be a quality gas with a very good additive Pac unlike ARCO or some other no name gasolines that only meets minimum additive requirement set by the US Gov...

RamGuy110 · Dec 23, 2022

I have 2500 miles on my 6.4 hemi with 4.10s, all stock so far. Its been -10 to -15 for most of this week and the combination of towing and running 4x4 most of the time, I'm down to 6.4 mpg - 7.1 mpg

mtofell · Dec 24, 2022

Grimlock said:
because anytime you get near the gas pedal it drops to like 6 so it destroys the average

I didn't read all 11 pages so maybe this has been covered but looking at any instant is not a measure of MPGs. You can coast downhill and get 99 or hit the throttle uphill and get 2. If pushing on the gas pedal and seeing low MPGs (for an instant) bums you out the best solution is to take the bus.

Dannycameo · Dec 24, 2022

I know this topic has been covered a million times and this thread seems to be the closest thing without starting a new one to post this question after reading many posts about mileage on the 6.4 l.
My 2022 power wagon now has 12,000 MI and taking off the 37 inch tires for winter down to a 35 inch Mickey Thompson Baja boss. My engine is running cooler obviously because of winter and not pushing the big 37-in tires, the surprising thing is my gas mileage is not really improved.I
I have taken five 600 MI trips in the last 3 months, currently on an Xmas trip to visit the in-laws.
Even at 55 mph with approximately 500 lb of passengers and gear I am only still averaging 10 and 1/2 miles per gallon on the highway. In the city it drops to 8.5 to 9 MPG.
I cannot understand why the mileage is so terrible, even at 55 mph. I can remember getting when the truck was new or relatively new 14 MPG with the 37s at 55 mph. The best I can get with the wind behind me is 12.5 MPG over one tank of gas, at 55 mph because of winter roads.
Anybody else getting these type of numbers? I keep reading about people with their new power wagons getting numbers much higher than this, and cannot figure out how even with stock 33 inch tires.

Wild one · Dec 24, 2022

Dannycameo said:
I know this topic has been covered a million times and this thread seems to be the closest thing without starting a new one to post this question after reading many posts about mileage on the 6.4 l.
My 2022 power wagon now has 12,000 MI and taking off the 37 inch tires for winter down to a 35 inch Mickey Thompson Baja boss. My engine is running cooler obviously because of winter and not pushing the big 37-in tires, the surprising thing is my gas mileage is not really improved.I
I have taken five 600 MI trips in the last 3 months, currently on an Xmas trip to visit the in-laws.
Even at 55 mph with approximately 500 lb of passengers and gear I am only still averaging 10 and 1/2 miles per gallon on the highway. In the city it drops to 8.5 to 9 MPG.
I cannot understand why the mileage is so terrible, even at 55 mph. I can remember getting when the truck was new or relatively new 14 MPG with the 37s at 55 mph. The best I can get with the wind behind me is 12.5 MPG over one tank of gas, at 55 mph because of winter roads.
Anybody else getting these type of numbers? I keep reading about people with their new power wagons getting numbers much higher than this, and cannot figure out how even with stock 33 inch tires.

You're not factoring in winter gas by the sounds of it.You can't compare winter milege numbers to summer milege numbers,not only is the amount of BTU's in a gallon of gas lower in the winter,everything is also alot harder to turn,especially the differentials.Throw in the fact you also spend more time spinning tires,especially on Calgary's streets.Plus this last weeks temps really put a crimp in milege numbers,as nothing really gets to full operating temps at -30,even if you drive to Edmonton.

392DevilDog · Dec 24, 2022

Christmas shopping... temperature went up from yesterday...it was -7.

Seeing if I can get to 4 today.

The temps also took 13 pounds of air out of my tires...ugh

White six four · Dec 24, 2022

Dannycameo said:
I keep reading about people with their new power wagons getting numbers much higher than this

I see this a lot on here comparing one's own mpg to someone else's. Even with the same exact truck unless they're driving the same roads same speed same wind conditions same temperature etc it doesn't mean a darn thing what someone else is getting mpg wise.

buckeyexx · Dec 24, 2022

Wild one said:
You're not factoring in winter gas by the sounds of it.You can't compare winter milege numbers to summer milege numbers,not only is the amount of BTU's in a gallon of gas lower in the winter,everything is also alot harder to turn,especially the differentials.Throw in the fact you also spend more time spinning tires,especially on Calgary's streets.Plus this last weeks temps really put a crimp in milege numbers,as nothing really gets to full operating temps at -30,even if you drive to Edmonton.

Plus if you remote start it kills your average according to the lie-o-meter. Or just manually starting and letting it run to clear ice off windshield. As cold as it is here right now I have been remote starting my truck and letting it warm up longer than usual. In the past two days I have gone down by about 2 mpg because of it. Went from 10.5 down to 8.6 but at least it’s nice and toasty.

turkeybird56 · Dec 24, 2022

392DevilDog said:
Christmas shopping... temperature went up from yesterday...it was -7.

Seeing if I can get to 4 today.

The temps also took 13 pounds of air out of my tires...ugh View attachment 509783

392: That is a good POINT to MAKE. With the extreme lowering of temps, all NEED to check their tire pressure and adjust. Even in TX, we were down to 12F, and yesterday, I went to my garage, fired up the ole air compressor and put 5 lbs of air in each tire. I lost 5 PSI due to the cold, SO all PPLS, especially the far North PPLs may want to check their PSI on tires also.

BIG_KAHUNA · Dec 24, 2022

my sierra1500 6.2 gets only 13 mpg on a good day...lol

Dannycameo · Dec 25, 2022

Wild one said:
You're not factoring in winter gas by the sounds of it.You can't compare winter milege numbers to summer milege numbers,not only is the amount of BTU's in a gallon of gas lower in the winter,everything is also alot harder to turn,especially the differentials.Throw in the fact you also spend more time spinning tires,especially on Calgary's streets.Plus this last weeks temps really put a crimp in milege numbers,as nothing really gets to full operating temps at -30,even if you drive to Edmonton.

Yeah I suppose those are all good points, I thought of the diffs, tranny etc warming up that's why I pressed the reset on the gas mileage counter once I've driven one full tank on the highway. So for example filled up in Edmonton got gas just south of Calgary, started the truck back up hit the reset button even at speed, so no city driving no red lights just pure highway driving. Yet someone else had a good point that unless you're driving the exact same roads with the same wind etc even with the exact same truck.

Dannycameo · Dec 25, 2022

392DevilDog said:
Christmas shopping... temperature went up from yesterday...it was -7.

Seeing if I can get to 4 today.

The temps also took 13 pounds of air out of my tires...ugh View attachment 509783

Very good point, when I left on this trip it was minus 33 Fahrenheit minus 36 Celsius, that's without wind chill, With remote start idle time even plugged in with the block heater and needing 4H to get to the highway by the time in the merge lane when I shifted back to two wheel drive and after all of the above I was around 4 miles per gallon. My tire pressure is set to 50 all the way around, and it was down 9 lb to start, according to the computer anyway, after 3 hours of driving it was almost back up to 50 even in those low of temps, plus that low tire pressure doesn't hurt, to make more contact on the pure ice roads to get through the city.

6.4l terrible mpg

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