No more DEF?

[Grayhound]

https://cdllife.com/2026/epa-remove...t=The U.S. Environmental Protection Agency,Ad

So looks like the def sensor will no longer be required. From what I am reading looks like this applies to all diesels. Is this another steps towards legal full delete?

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[DylanM]

Nope, it just removes the requirement for the PCM to derate or to prevent engine starting when the DEF system has a fault or thinks it's out of fluid. If you pay attention when reading the article, they're suggesting the manufacturers change the monitoring system to being based on NOx sensor readings instead of DEF sensor readings. Emissions equipment standards are still in effect.

 

[Tr4ckD4ys]

If you can’t do, don’t want to or have not done a delete, just treat your (emissions-compliant) Diesel nicely with good fuel, good additives, fresh DEF if necessary and you won’t have any problems. It’s not like all modern diesels throw check engine lights all the time. They throw them because of not having been driven or treated right. Now how “right” is defined is a point of contention, but if you go at least once a week 70mph for 30+ minutes you shouldn’t have any issues.

 

[Grayhound]

I get that the standards stay the same, but removing a hardware requirement feels like a pivot. The EPA is finally admitting these sensors are a reliability nightmare. If they are moving toward monitoring the tailpipe (NOx) instead of the fluid tank, it feels like they are taking the system apart piece by piece. Do you think the end goal is to eventually phase out the complex hardware entirely if they can meet the numbers with just tuning and better engine tech?

 

[DylanM]

It is a pivot insomuch as hopefully moving towards something more reliable and less needlessly restrictive to vehicle usability, but I feel it's a far cry from a step towards a full legal delete.

To draw a parallel, on a gas vehicle if an o2 sensor takes a dump or the cat efficiency drops below acceptable threshold value, the vehicle can still be driven in a generally normal fashion. With diesels as the way things are/were, one DEF sensor flaking out would result in a countdown to the PCM turning the vehicle into an expensive paper weight until said sensor fault is fixed. Two similar situations with similar potential negative effects on emissions, but two entirely different impacts upon the ability to continue to use or drive the vehicle depending on what type of fuel they use.

So long as they stick to controlling emissions of items such as NOx, particulate, and carbon monoxide, I really don't see things moving the "delete" direction any time soon.

 

[Grayhound]

I think that comparison makes a lot of sense. I hadn’t looked at it as compared to the way a gas engine is treated.

At the end of the day I’m not looking to roll coal, I just want simplicity and reliability back.

to be fair I have taken care of my emissions system as best I can without issue at 96k miles.

 

[Vimby210]

I get that the standards stay the same, but removing a hardware requirement feels like a pivot. The EPA is finally admitting these sensors are a reliability nightmare. If they are moving toward monitoring the tailpipe (NOx) instead of the fluid tank, it feels like they are taking the system apart piece by piece. Do you think the end goal is to eventually phase out the complex hardware entirely if they can meet the numbers with just tuning and better engine tech?

It isnt a hardware requirement they are removing. It will be a software reprogram.

 

[ColonelSanders]

Do you think the end goal is to eventually phase out the complex hardware entirely if they can meet the numbers with just tuning and better engine tech?

The end goal is to make you feel like they are doing something so you poll favorably. Lip service.

 

[Bayrat]

So perhaps good fuel will be sold again. The crap we have now redly absorbs water, promoting bacterial growth, so additives are required to counter both the low cetane rating and the bug growth in the fuel. Despite every effort, I had them plug both of my CUMMINS filters on US95. I had just fueled up at a station on US17 in Fredericksburg Va with the contamination growing in their tanks. I called them and they stated that the tanks had just been cleaned, sure they did. I have a tank at home which receives regular treatment with biocide additives just to keep it clear of that nonsense.

 

[Ratbert]

So perhaps good fuel will be sold again. The crap we have now redly absorbs water, promoting bacterial growth, so additives are required to counter both the low cetane rating and the bug growth in the fuel. Despite every effort, I had them plug both of my CUMMINS filters on US95. I had just fueled up at a station on US17 in Fredericksburg Va with the contamination growing in their tanks. I called them and they stated that the tanks had just been cleaned, sure they did. I have a tank at home which receives regular treatment with biocide additives just to keep it clear of that nonsense.

Good fuel sold again? Are you talking about when it was common for diesel to contain 2,000 to 5,000 ppm sulfur? That's soot and acid that clogs your engine.

It's now down to 15 ppm in the US, but ours is still sludge in comparison to European diesel, which results in a much smoother running engines. European diesel is also significantly more consistent from one source to the next.

The issues with old contaminated diesel will just get worse as fewer and fewer vehicles use it year by year. That is, it simply sits there longer now before being sold.

 

[Bayrat]

Good fuel sold again? Are you talking about when it was common for diesel to contain 2,000 to 5,000 ppm sulfur? That's soot and acid that clogs your engine.

It's now down to 15 ppm in the US, but ours is still sludge in comparison to European diesel, which results in a much smoother running engines. European diesel is also significantly more consistent from one source to the next.

The issues with old contaminated diesel will just get worse as fewer and fewer vehicles use it year by year. That is, it simply sits there longer now before being sold.

I never had an issue with the old high sulfur diesel, never. During the winter months it was always mixed with kerosene either at the pumps or the supplier would do it. No issues not plugging up anything, just a good, long running engine with fuel which did not collect water or require additives to raise cetane.

 

[Twisted10]

We might see a little relaxation on delete companies and those of us who do delete.

I actually got stopped by the NY DEC (fish cops) for my deleted cummins. He heard it (no speeding, no rolling coal). Ive been driving deleted diesels for years and never had an issue. NY does not require emissions testing.... No ticket.

 

[AVENTUS]

I get that the standards stay the same, but removing a hardware requirement feels like a pivot. The EPA is finally admitting these sensors are a reliability nightmare. If they are moving toward monitoring the tailpipe (NOx) instead of the fluid tank, it feels like they are taking the system apart piece by piece. Do you think the end goal is to eventually phase out the complex hardware entirely if they can meet the numbers with just tuning and better engine tech?

I’m actually wondering if my dream of slow smooth grandpa highway cruising, with a healthy diet of additives, and plenty of DEF, and a light foot, and a tune that significantly decreases torque and HP, and also increases MPG, might meet those numbers without all the disgustingly expensive sensors/etc ? Are there very audibly quiet (with gentle pedal habits) “weight reduction” steps that can be taken ?

 

[Grayhound]

I’m running the GDE tune I hear the motor sounding different but not louder

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