Fuel Mileage and Regens

[Diesel85]

Since the new 2025 engine has been out, I'm sure a few folks have already racked up some miles on their rig.

Can anyone care to share any experiences with the 7th injector design on the new emissions system?

Key points:

• Fuel mileage
• Regen length (time and mileage)
• Lessened oil dilution

 

[C M McCormick]

 

[Terry]

All I can report is at 420 miles mine has not done a regen yet. The exhaust filter says it’s up to 10% and the DEF gauge has not moved yet either. Many of those miles are on the highway running empty.

 

[Signal73]

related;


https://hdrams.com/forum/index.php?threads/2025-cummins-regen-observations.19294/

 

[Diesel85]

related;


https://hdrams.com/forum/index.php?threads/2025-cummins-regen-observations.19294/

Thanks for sharing! Good info here!

 

[Terry]

Well apparently, my new truck did its first regen yesterday. I have had the DPF gauge up on the instrument cluster for some time and noticed it had jumped up from 10% to 20 % when I was driving yesterday. When I drove it back home about 30 miles, about half highway the rest around 35 mph I never saw anything informing me that it was doing a regen. But suddenly the DPF gauge dropped from 20% to 0%, a few minutes later I parked it in my garage.

When I got out of the truck there was an odor of something burning. After inspecting it I found that the part# decal on the tail pipe had melted and burned. I was surprised that there wasn’t any instrument panel notification of an active exhaust cleaning in progress as I had seen before on Ford and GM diesel trucks. The truck has 475 miles on it now about half and half city and highway, all running empty.

It looks like I’m averaging a little over 18mpg so far, the dealer filled the 50 gallon fuel tank when I took delivery. I’m still showing almost 400 miles to empty.

 

[Diesel85]

Well apparently, my new truck did its first regen yesterday. I have had the DPF gauge up on the instrument cluster for some time and noticed it had jumped up from 10% to 20 % when I was driving yesterday. When I drove it back home about 30 miles, about half highway the rest around 35 mph I never saw anything informing me that it was doing a regen. But suddenly the DPF gauge dropped from 20% to 0%, a few minutes later I parked it in my garage.

When I got out of the truck there was an odor of something burning. After inspecting it I found that the part# decal on the tail pipe had melted and burned. I was surprised that there wasn’t any instrument panel notification of an active exhaust cleaning in progress as I had seen before on Ford and GM diesel trucks. The truck has 475 miles on it now about half and half city and highway, all running empty.

It looks like I’m averaging a little over 18mpg so far, the dealer filled the 50 gallon fuel tank when I took delivery. I’m still showing almost 400 miles to empty.

Thanks for posting this! Very helpful!

 

[AH64ID]

Well apparently, my new truck did its first regen yesterday. I have had the DPF gauge up on the instrument cluster for some time and noticed it had jumped up from 10% to 20 % when I was driving yesterday. When I drove it back home about 30 miles, about half highway the rest around 35 mph I never saw anything informing me that it was doing a regen. But suddenly the DPF gauge dropped from 20% to 0%, a few minutes later I parked it in my garage.

When I got out of the truck there was an odor of something burning. After inspecting it I found that the part# decal on the tail pipe had melted and burned. I was surprised that there wasn’t any instrument panel notification of an active exhaust cleaning in progress as I had seen before on Ford and GM diesel trucks. The truck has 475 miles on it now about half and half city and highway, all running empty.

It looks like I’m averaging a little over 18mpg so far, the dealer filled the 50 gallon fuel tank when I took delivery. I’m still showing almost 400 miles to empty.

Ram doesn’t notify drivers of regular active regens.

How many engine hours?

 

[Terry]

Ram doesn’t notify drivers of regular active regens.

How many engine hours?

With all of the gauges that it has you would think it could tell you about an active regen in progress. But mine went from 20% straight to 0%. When I picked up my truck it already showed 4 idle hours, now it shows 28 hours total with 8 idle hours. It must be counting sitting in stop and go traffic as I don’t let my engine’s idle except a short cool down after a loaded run before shutting it down.

 

[AH64ID]

With all of the gauges that it has you would think it could tell you about an active regen in progress. But mine went from 20% straight to 0%. When I picked up my truck it already showed 4 idle hours, now it shows 28 hours total with 8 idle hours. It must be counting sitting in stop and go traffic as I don’t let my engine’s idle except a short cool down after a loaded run before shutting it down.

Stop and go is idle time since the engine is idling, even if it’s in gear. I’m pretty sure my 2022 also counted slow speed driving below ~3-5 mph as idle.

What gauge cluster do you have?

The gauge dropping from 20-0 could be from active or passive regen.

 

[Terry]

Stop and go is idle time since the engine is idling, even if it’s in gear. I’m pretty sure my 2022 also counted slow speed driving below ~3-5 mph as idle.

What gauge cluster do you have?

The gauge dropping from 20-0 could be from active or passive regen.

Well it’s a Limited so it’s got everything as far as the cluster and center display. Actually, the truck has every option you can order on it except the trailer back up steering as I wanted the auxiliary switch package instead, you can’t get both at the same time. Because the tail pipe got so hot that it burned off that decal I’m sure it was an active regen. I’ve driven it on the highway many times before and it had never done that before.

 

[AH64ID]

Well it’s a Limited so it’s got everything as far as the cluster and center display. Actually, the truck has every option you can order on it except the trailer back up steering as I wanted the auxiliary switch package instead, you can’t get both at the same time. Because the tail pipe got so hot that it burned off that decal I’m sure it was an active regen. I’ve driven it on the highway many times before and it had never done that before.

Sounds like you have the full digital dash. For some reason that dash doesn’t indicate an active regen is in progress, where the smaller analog/digital hybrid dashes do (at least up thru ‘24, unconfirmed on ‘25).

Even my ‘25 MB Sprinter doesn’t alert the user to an active regen, but it does show on the DPF page if you’re watching it.

 

[Terry]

I guess that’s better than my friends F350 6.7, he says almost every time he uses it the dash says “drive to clean exhaust filter”.
He’s had it back to Ford many many times under warranty and they keep telling him that’s it’s normal.

 

[AH64ID]

I guess that’s better than my friends F350 6.7, he says almost every time he uses it the dash says “drive to clean exhaust filter”.
He’s had it back to Ford many many times under warranty and they keep telling him that’s it’s normal.

That’s not normal, unless he bought the wrong vehicle for his application.

Tell him to run some Archoil 6400d.

 

[Shiner]

So what I am seeing, the 25’s mileage isn’t anything to get excited over…..just fill the tank and go. My 2021 consistently knocks down 19-20 mpg. Once in a great while I can squeeze out a 21-22 number when the stars are aligned just right.

 

[Diesel85]

So what I am seeing, the 25’s mileage isn’t anything to get excited over…..just fill the tank and go. My 2021 consistently knocks down 19-20 mpg. Once in a great while I can squeeze out a 21-22 number when the stars are aligned just right.

I agree. When I did my long test drive, I was getting the same numbers as I'd expect on any modern 6.7l Cummins.

Maybe bringing the emissions equipment closer to the engine and the 7th injector might save on a tad bit of fuel down the line. I guess we sit back and wait and get some bigger averages.

 

[Ozymandias]

There is only so much juice in a lemon to squeeze out.
At a certain point, no matter how hard you press you don't get anymore out of it.

 

[Shiner]

There is only so much juice in a lemon to squeeze out.
At a certain point, no matter how hard you press you don't get anymore out of it.

True. And it takes a certain amount of fuel to do a given amount of work, only thing that can change is how efficient it is doing it.