How Hard Does a 6.7L Cummins Need to Be Worked To Avoid Issues?

[wyvern]

Hey everyone. I’ve never owned an emissions regulated diesel before and I am confused about the level of “working” these engines need to avoid potential issues.

Basically everything you read about these engines claim that “as long as you work them, there are no issues”. However, is spirited highway driving considered working them? Or is this limited to high capacity towing?

I will be using my truck for long highway trips and occasional hauling. Some of these comments worry me insofar as not working the truck enough such that it always has to go into active regen. I’d rather rely more on passive regen for long term engine health.

Any opinions appreciated.

 

[AH64ID]

Highway driving is fine, the emissions system doesn't like stop and go, short trips, idling, and low speeds.

 

[firemansdiesel]

Drive the truck and enjoy it.

 

[tchur1]

Hey everyone. I’ve never owned an emissions regulated diesel before and I am confused about the level of “working” these engines need to avoid potential issues.

Basically everything you read about these engines claim that “as long as you work them, there are no issues”. However, is spirited highway driving considered working them? Or is this limited to high capacity towing?

I will be using my truck for long highway trips and occasional hauling. Some of these comments worry me insofar as not working the truck enough such that it always has to go into active regen. I’d rather rely more on passive regen for long term engine health.

Any opinions appreciated.

I only tow 6 months a year, daily my truck, and am on the highway at most 1x per week and have not had any issues in the first 20k miles of ownership. Highway trips seem to produce some passive regen, towing is great for it.

I can't find it right now but @mbarber84 just spelled this out well in another post. "Driving it hard" doesn't mean flooring it from stoplights and hammering it to the redline, but rather prolonged driving under load (highway speeds unloaded seem to be good enough for this). The emissions systems seem to really struggle with a lot of idling and slow speed/stop and go traffic. Avoid a ton of that and you should be totally fine.

 

[Blythkd1]

I agree with the highway driving comments. I routinely drive 700 miles empty then pick up a large 5th wheel, deliver it and go home. So basically, my miles are 50/50 empty highway/ heavy towing. I'm pushing 50k miles now and rarely ever see a regen except for the ones that are triggered by engine hours.

 

[mbarber84]

I only tow 6 months a year, daily my truck, and am on the highway at most 1x per week and have not had any issues in the first 20k miles of ownership. Highway trips seem to produce some passive regen, towing is great for it.

I can't find it right now but @mbarber84 just spelled this out well in another post. "Driving it hard" doesn't mean flooring it from stoplights and hammering it to the redline, but rather prolonged driving under load (highway speeds unloaded seem to be good enough for this). The emissions systems seem to really struggle with a lot of idling and slow speed/stop and go traffic. Avoid a ton of that and you should be totally fine.

Indeed.
Towing on the interstate for a decent length of time, even if infrequently, is very helpful to the emissions system as a whole. It gets everything hot, works the engine, and provides the ideal conditions for passive regeneration. You want to achieve passive regeneration as much as possible because it’s “free” compared to active regeneration which “costs” you. Active regeneration burns fuel to accomplish emissions requirements, rather than being used to make the truck move, it increases the risk of fuel dilution in the oil, and exposes the emissions system to higher levels of heat that ultimately shorten the lifespan of the emissions components.

When you see people giving advice about “go out and beat on it”, “drive it hard”, “drop two gears and redline it”……none of that is doing anything progressive towards aiding regeneration. In fact, bouncing the throttle around that much and feeding the truck excessive fuel for short periods can actually increase soot-loading. It’s terrible advice and should never be heeded. The same holds true when any diagnostic trouble codes appear. Rule #1 is always read the codes. Buy or gain access to a scanner and see what codes are in the computer. They will very likely lead you in the right direction. Without understanding the codes, a lot of suggestions are blind and will not necessarily help your situation. You could inadvertently spend a lot of time and effort attempting to repair the wrong parts, or create more issues.

 

[techman]

IMHO the diesel particulate gauge should be removed. It is the source of more angst for new owners and a complete distraction from driving. If the truck has a problem during daily use it will let you know.

Drive it, keep up with scheduled maintenance, and use good diesel and you will be fine.

 

[joshuaeb09]

Mine is a highway cruiser and occasional tow rig with very infrequent short tripping. Down here in Texas I have no issues getting passive regen empty going 70mph+. I seem to get the best DPF clean outs when I've spent several hours on toll roads doing 85mph and that's usually always empty. It seems to be the city folk who are putting the truck through tons of short trips that have the most issues.

 

[jebruns]

IMHO the diesel particulate gauge should be removed. It is the source of more angst for new owners and a complete distraction from driving. If the truck has a problem during daily use it will let you know.

Drive it, keep up with scheduled maintenance, and use good diesel and you will be fine.

Somewhat agree. I don't understand folks watching it, or worrying about regen's. I'm on my 2nd Ram Cummins truck and I've never paid attention to any of it. I'm sure my trucks have regen'd, I just don't know, and don't care, when or how often.

OTOH, maybe there is something there I'm just not understanding. So maybe it's good for that information to be available to the folks that want to watch it.

 

[mbarber84]

IMHO the diesel particulate gauge should be removed. It is the source of more angst for new owners and a complete distraction from driving. If the truck has a problem during daily use it will let you know.

Drive it, keep up with scheduled maintenance, and use good diesel and you will be fine.

Somewhat agree. I don't understand folks watching it, or worrying about regen's. I'm on my 2nd Ram Cummins truck and I've never paid attention to any of it. I'm sure my trucks have regen'd, I just don't know, and don't care, when or how often.

OTOH, maybe there is something there I'm just not understanding. So maybe it's good for that information to be available to the folks that want to watch it.

I would disagree. Having more knowledge at your fingertips helps you to better understand what your truck does, when it does it, and why. I like being able to track and identify when the truck regenerates because it allows me to better maintain the truck. Specifically, I am able to monitor when the truck will go into a regeneration and can plan to continue driving until the cycle is complete. While the system will “pause” and “resume” when you stop or shut the truck off, that is not the best strategy for maintaining the health of the DPF. It is far better to allow the cycle to complete in one session rather than interrupting it. Also, not all frequent regeneration issues will generate a code. There have been several trucks that are going 150 miles on a regeneration and can attribute that problem back to running the incorrect engine air filter. I should know, as I was one of those. If it had not been for the DPF gauge and the notices for regeneration, it would have been far more difficult to detect the frequency that those cycles were happening on. Switching the air filter from 68517554AA back to the correct 53034051AB made a substantial improvement in how the truck drove and I immediately noticed a difference in how much the truck was regenerating. Like anything else in life, knowledge is a useful thing. The folks who obsess over the gauge may not fully understand how the truck works and a little tidbit of shared knowledge goes a long way in helping others understand how their truck operates. I can’t think of a single situation where more monitoring of your trucks functions and understanding of how your truck operates would be a bad thing. DPF gauge included.

 

[jebruns]

Well, we're all different. I've never seen a "notice for regeneration" in either of my trucks, nor any other signs a regen is going on. But they have not been daily drivers, they are for towing. If it helps you, that's great. I'll continue to ignore it, personally.

 

[Blythkd1]

IMHO the diesel particulate gauge should be removed. It is the source of more angst for new owners and a complete distraction from driving.

In the past I probably would have agreed with you, and I paid extra for mine.

But now since I've never seen anything register on the gauge in almost 50k miles, I just ignore it. The only time that screen ever changed was when I triggered a stationary regen. Last time I'll ever do that unless it somehow becomes necessary. I thought the sumbitch was gonna burn down.

 

[gimmie11s]

Completely overblown internet issue. If youre not idling the truck 10 hours per day (which many fleet companies actually do) then you'll never have to worry about this "issue".

My truck is nothing but short city trips, occasional highway trip to work 2 or 3x per month and tows 6-10x per year. Never any issues, almost 20k miles today. 0 issues thus far.

Ive seen the DPF gauge read over 0% literally 0 times. Agree, pointless gauge.

 

[mbarber84]

Completely overblown internet issue. If youre not idling the truck 10 hours per day (which many fleet companies actually do) then you'll never have to worry about this "issue".

My truck is nothing but short city trips, occasional highway trip to work 2 or 3x per month and tows 6-10x per year. Never any issues, almost 20k miles today. 0 issues thus far.

Ive seen the DPF gauge read over 0% literally 0 times. Agree, pointless gauge.

Far from correct. I just spoke with a gentleman who’s brand new truck with 550 miles on it is running regeneration cycles every 75-100 miles. That is definitely not correct. He should be able to achieve at least 300-500 before there’s an issue even if he’s moderately driving the truck. No check engine lights or codes. When towing heavily with these trucks, you can usually go about 1,000 miles or so between active regeneration cycles. (They would be triggered by the 24 hour timer in this case, as repetitive towing on the interstate would be keeping the DPF soot-free by means of passive regeneration). If this gentleman’s truck is regenerating every 100 miles, he’s regenerating TEN times as much as a truck that’s frequently towing. Active regeneration cycles will ultimately lead to some level of fuel dilution in the engine oil. It is unavoidable given the nature of the way the system injects fuel for regen cycles. That gauge is there to help monitor what’s going on. It’s just as important as every other gauge provided. It’s the operators choice to ignore it, as they can ignore any other gauge as well, but the data it provides is part of monitoring the trucks functions just like anything else.

 

[gimmie11s]

Far from correct. I just spoke with a gentleman who’s brand new truck with 550 miles on it is running regeneration cycles every 75-100 miles. That is definitely not correct. He should be able to achieve at least 300-500 before there’s an issue even if he’s moderately driving the truck. No check engine lights or codes. When towing heavily with these trucks, you can usually go about 1,000 miles or so between active regeneration cycles. (They would be triggered by the 24 hour timer in this case, as repetitive towing on the interstate would be keeping the DPF soot-free by means of passive regeneration). If this gentleman’s truck is regenerating every 100 miles, he’s regenerating TEN times as much as a truck that’s frequently towing. Active regeneration cycles will ultimately lead to some level of fuel dilution in the engine oil. It is unavoidable given the nature of the way the system injects fuel for regen cycles. That gauge is there to help monitor what’s going on. It’s just as important as every other gauge provided. It’s the operators choice to ignore it, as they can ignore any other gauge as well, but the data it provides is part of monitoring the trucks functions just like anything else.

My post is 100% correct considering my vehicle currently has 20k on it and hasnt skipped a beat a single time.

The anecdote you cite is obviously a problematic vehicle that needs to be inspected by Ram.

 

[mbarber84]

My post is 100% correct considering my vehicle currently has 20k on it and hasnt skipped a beat a single time.

The anecdote you cite is obviously a problematic vehicle that needs to be inspected by Ram.

It’s easy to sit back and dispel things as rumors or myths when your own truck is functioning fine.

There is currently a significant number of trucks demonstrating the exact same behavior. Predominantly 2022 and 2023 model year trucks. Like anything else mass produced there can be failures. The quantity of which can vary greatly. I can assure you this is a widespread problem right now. I have a lot of good connections in the industry and several of them are highly experienced techs for Chrysler. Two of them have independently told me that the regeneration frequency problem has been plaguing their service bays lately. All centered around 2022’s and 2023’s. One in particular mentioned that he’s noted a significantly higher pressure reading in the DPFs of some 2022’s when compared to 2021 and down. Remember the vast majority of these trucks were manufactured at the tail end of the COVID years. Parts supply chains were a mess, and utterly unpredictable (so much so that they built every 2022 Cummins truck without a PM sensor). It isn’t unreasonable to suggest that there’s a more prolific problem afoot here, and something that merits further investigation. The majority of the users who experience these odd regenerative issues would not be aware of the trucks actions if it wasn’t for the gauge telling them that the truck is running in regeneration.

 

[wyvern]

Honestly sometimes it sounds like the 2021 model year trucks are the unicorns. It seems like every other year just has these achilles heels that make them fail in some spectacular way.

 

[Blythkd1]

That gauge is there to help monitor what’s going on. It’s just as important as every other gauge provided. It’s the operators choice to ignore it, as they can ignore any other gauge as well, but the data it provides is part of monitoring the trucks functions just like anything else.

Having a hard time figuring out the value of a gauge that never reads anything but 0. Literally NEVER read anything but ZERO. Maybe it's valuable for some guys but not me. That's why I ignore it. It's pointless for me.

I guess mine just regens every 24 hours, which at 50mph avg is every 1200 miles. Not bad. Seems like the best diesel out there right now.

 

[mbarber84]

Honestly sometimes it sounds like the 2021 model year trucks are the unicorns. It seems like every other year just has these achilles heels that make them fail in some spectacular way.

The trucks built in 2021 were better trucks. That I can attest to. I’m very happy I ordered my 2022 when I did. Built 10/9/21 and delivered 11/29/21. It would seem I missed the Aisin K1 snap ring issue and my DPF regenerates as it should. It looks as though the bottom fell out somewhere around May - June of 2022 and it got progressively worse from there.

 

[mbarber84]

Having a hard time figuring out the value of a gauge that never reads anything but 0. Literally NEVER read anything but ZERO. Maybe it's valuable for some guys but not me. That's why I ignore it. It's pointless for me.

I guess mine just regens every 24 hours, which at 50mph avg is every 1200 miles. Not bad. Seems like the best diesel out there right now.

The gauge is telling you something when it reads 0%. That’s DPF speak for, you’re doing things right. If it never moves off zero, and you’re only regenerating every 24 hours, that is literally the peak of performance when it comes to these emissions systems. Count your blessings. There are a lot of operators out there with trucks regenerating every 100 miles while towing repetitively.