6.4l terrible mpg

[4xdad]

How do you see out the window if you don’t warm it up

 

[06 Dodge]

How do you see out the window if you don’t warm it up

Many don't around my area, they start the engine, drop it in gear then hammer the go fast pedal, because they can't t see well out of the windshield because its all fogged up they then wonder how they got into a wreck..

 

[DrTron]

Being a Mississippi resident what you call cold and what alot of the planet calls cold are to differant entities.Alot of vehicles don't get shut off where the temps are -45 or colder if you don't have access to a 120 volt outdoor plug-in to plug the block heater in,so they'll sit an idle 24/7 except to put fuel in them or check the oil.

I have not lived all my life in MS, only moved here recently. And I think the temperature in question was 50F. So not even necessary to scrape the windows free of ice.
And of course there are temperatures on this planet where Diesel fuel gums up and such. I've seen it happen. That obviously requires a different approach, then it's less about wear and tear and more about to get moving at all. But I suppose that doesn't apply to >99% of the world's population.

A block heater (at least the ones I had on RAMs) don't do much to warm up the engine to operating temperatures. They're not nearly powerful enough for that. That's for the previous point of getting underway altogether.

There are two systems that can warm up the engine without putting wear on it. Both rely on a separate pump in the cooling line that circulates and heats up the coolant to get the engine out of that harmful cold-start window. One uses the vehicle's fuel to generate heat, the other is a plug-in system that runs off electricity.

 

[dhay13]

My neighbor starts hers up 3x each morning and lets it run the 15 minute cycle each time. And she only drives about 12 miles to work. This is even on 50* days. The other day it was about 50* and she started it 3x as per her usual schedule. My bedroom window is about 10' from her car so I can hear the horn beep every time she starts it. And she gets a new car every 3 years. She just got a new Chevy Blazer a few months ago. Bjut this is on every vehicle and makes no difference what the temp is outside. Still lets it run 45 minutes every morning.

Oh...and they also replace their brakes like crazy. I swear they replace them every 10,000 miles. Every few months I go outside and he is in the garage with one of their cars on jackstands replacing pads and rotors...lol

 

[DrTron]

That certainly seems excessive ;-)

 

[Bonnie Blue Flag]

My experience with the 2024 2500 6.4 around town the MPG is in the 8-10 mpg range.

On the highway it is much better.

Put it in cruise control between 55-65 and you can get 18-24 mpg. The 24 is possible at about 55 mph if your driving on relatively flat highway.

Previously I had a 1500 with the 5.7. Around town I would like to say 12-14 mph was possible and Highway north of 24 mph in cruise control was possible at 55-65 mph.

So the 6.4 is a pig around town.

 

[dieselscout80]

My experience with the 2024 2500 6.4 around town the MPG is in the 8-10 mpg range.

On the highway it is much better.

Put it in cruise control between 55-65 and you can get 18-24 mpg. The 24 is possible at about 55 mph if your driving on relatively flat highway.

Previously I had a 1500 with the 5.7. Around town I would like to say 12-14 mph was possible and Highway north of 24 mph in cruise control was possible at 55-65 mph.

So the 6.4 is a pig around town.

My 2020 6.4 2500 with 4.10 gears gets impressive mileage for what it is.

The more skinny pedal application equals less MPG.

I mostly drive at less than 2200 rpm and get good MPG.

 

[RichieW13]

My experience with the 2024 2500 6.4 around town the MPG is in the 8-10 mpg range.

On the highway it is much better.

Put it in cruise control between 55-65 and you can get 18-24 mpg. The 24 is possible at about 55 mph if your driving on relatively flat highway.

Previously I had a 1500 with the 5.7. Around town I would like to say 12-14 mph was possible and Highway north of 24 mph in cruise control was possible at 55-65 mph.

So the 6.4 is a pig around town.

24mpg? I can't imagine getting that. My best tank ever is 16.4mpg. But then I've never tried staying at 55mph (unless I'm towing).

 

[dieselscout80]

24mpg? I can't imagine getting that. My best tank ever is 16.4mpg. But then I've never tried staying at 55mph (unless I'm towing).

I think he meant the mpg counter will show that on a level road with no head wind, but as soon as it changes to up hill it goes down.

I see it on level road too. However it goes down immediately on a grade. When coasting downhill it can hit 99 mpg.

That said I think my lie O meter reads .7 mpg high, but I can and have hand calculated 18 mpg empty.

 

[Tulecreeper]

I think he meant the mpg counter will show that on a level road with no head wind, but as soon as the it changes to up hill it goes down.

I see it on level road too. However it goes down immediately on a grade. When coasting downhill it can hit 99 mpg.

That said I think my lie O meter reads .7 mpg high, but I can and have hand calculated 18 mpg empty.

If I don't disengage the MDS I can sometimes get low 20's on the freeway.

 

[TNGA]

My mileage display typically says about 15.7-16.5; my hand-calculated results are about 14.3, but each tank typically includes a lot of freeway driving with 70 mph speed limits.

 

[Fatbob Frank]

MDS is a funny thing.
I used to disable it in my 5.7 1500 Laramie because it was so intrusive in noise and vibration...
But I've never bothered in my PW.
Even with my glass packed single exhaust I can never notice when it's active...

 

[RichieW13]

What is MDS?

 

[Fatbob Frank]

Multi Displacement System or Cylinder Deactivation.

 

[dieselscout80]

Multi Displacement System or Cylinder Deactivation.

Yep

It lets the hemi run on 4 cylinders rather than eight.

 

[Tulecreeper]

What is MDS?

Yep

It lets the hemi run on 4 cylinders rather than eight.

Yes, but I rarely let the MDS do it's thing. #1 - if I wanted a 4-cyl truck, I'd have bought one; #2- it bugs me when it kicks in because I can feel a difference in the gas pedal, and hear this sub-audible rumble from behind the firewall. I will let it do it's thing for a while when I get up to highway speed. You know, just to keep it 'lubed up', so to speak.

To disengage it, simply use your ERS buttons on the steering wheel. They let you put the transmission in any gear you want. I just run it up to 8 and let it do it's thing.

 

[BlackGold6.4]

the MDS on the 6.4 2500 barely works due to power to weight ratio, I noticed this going from a 1500 5.7 MDS to a 2500 MDS. For me I noticed that 4 cyl. mode worked between 70-90 Km range not saying it didn't in other ranges but it is noticeable at that speed. I have the 410 gears so that might be a factor too.

 

[Tulecreeper]

the MDS on the 6.4 2500 barely works due to power to weight ratio, I noticed this going from a 1500 5.7 MDS to a 2500 MDS. For me I noticed that 4 cyl. mode worked between 70-90 Km range not saying it didn't in other ranges but it is noticeable at that speed. I have the 410 gears so that might be a factor too.

I notice with my 2500 that with MDS disengaged I get maybe 16-18 MPG at highway speed. When I let it do its thing, my mileage goes up to about 20-22 MPG. But that is at 60 MPH and not towing. And even without towing, in city traffic I'm back down to 12-14 MPG even with MDS.