24 Hour Regens No Longer Happen

[Will_T]

I try to monitor all I need on one page. I change between EGT 1 & 2, can't decide which I like best, lean towards 2View attachment 54493

On another note, I see your DEFCON is at 26. I thought I saw somewhere Cummins says it is supposed to be 32.5%. +or- 1.5%?

Edit: I found the Cummins bulletin where it said, "The urea content of DEF solution must be 32.5 percent ± 1.5 percent by weight. Maybe that is not what the DEFCON PID is measuring?

 

[John Jensen]

On another note, I see your DEFCON is at 26. I thought I saw somewhere Cummins says it is supposed to be 32.5%. +or- 1.5%?

Edit: I found the Cummins bulletin where it said, "The urea content of DEF solution must be 32.5 percent ± 1.5 percent by weight. Maybe that is not what the DEFCON PID is measuring?

Good eye. When that picture was taken I used 1 gal of distilled water to 2.5 gallons of DEF which makes it 26%. The bad DEF alarm doesn't go off until DEF hits 22%. I am currently running pure Walmart DEF and it's reading 33%. DEF has to spec out to at least 32.5%.

 

[Aketay]

All I know is that every 24 hours of engine run time, the regen will start regardless of the condition of the DPF. Every 2 + days I see regen happening. Truck has 388,000 miles and I know the sounds of regen really well.

 

[John Jensen]

Good eye. When that picture was taken I used 1 gal of distilled water to 2.5 gallons of DEF which makes it 26%. The bad DEF alarm doen't go off until DEF hits 22%. I am currently running pure Walmart DEF and it's reading 33%. DEF has to spec out at 32.5%.

All I know is that every 24 hours of engine run time, the regen will start regardless of the condition of the DPF. Every 2 + days I see regen happening. Truck has 388,000 miles and I know the sounds of regen really well.

Great! That's exactly what it is supposed to do

 

[thecastle]

To test this every 24 hour regen observation knowing I would be driving for more than 24 hours; I left my 2019 3500 HO on the DPF display on my recent 2400 mile round trip between Houston and Indiana. I drove the truck over 36 hours (cumulatively) and did not have an active regen until it hit 32.5 hours (from trip computer). But that was also at the same time my DPF showed 50% blocked. So I'm not certain if it was time or sooting up that triggered an active regen. But I will say my 2019 after having the fuel pump recall done does not do an active regen every 24 hours based on monitoring this trip. My truck sat at 0% blocked most of the trip (including at 24 hours drive time), it wasn't until I headed back through Illinois and got stuck in major road construction I say the plugged level climb, which likely is what triggered an active regen while passing through MO. I wonder if the updated fuel pump programing changed the behavior? My truck only seems to now do an active regen based on DPF level not arbitrarily based on time.

 

[John Jensen]

To test this every 24 hour regen observation knowing I would be driving for more than 24 hours; I left my 2019 3500 HO on the DPF display on my recent 2400 mile round trip between Houston and Indiana. I drove the truck over 36 hours (cumulatively) and did not have an active regen until it hit 32.5 hours (from trip computer). But that was also at the same time my DPF showed 50% blocked. So I'm not certain if it was time or sooting up that triggered an active regen. But I will say my 2019 after having the fuel pump recall done does not do an active regen every 24 hours based on monitoring this trip. My truck sat at 0% blocked most of the trip (including at 24 hours drive time), it wasn't until I headed back through Illinois and got stuck in major road construction I say the plugged level climb, which likely is what triggered an active regen while passing through MO. I wonder if the updated fuel pump programing changed the behavior? My truck only seems to now do an active regen based on DPF level not arbitrarily based on time.

Interesting. I have not driven 24 hours since I had the recall so I can't compare yet. Doing an active regen based on the DPF condition makes more sense than the 24 hour rule. Hopefully, there will be others able to confirm your experience. I won't ne taking any truck trips until September.

 

[AH64ID]

To test this every 24 hour regen observation knowing I would be driving for more than 24 hours; I left my 2019 3500 HO on the DPF display on my recent 2400 mile round trip between Houston and Indiana. I drove the truck over 36 hours (cumulatively) and did not have an active regen until it hit 32.5 hours (from trip computer). But that was also at the same time my DPF showed 50% blocked. So I'm not certain if it was time or sooting up that triggered an active regen. But I will say my 2019 after having the fuel pump recall done does not do an active regen every 24 hours based on monitoring this trip. My truck sat at 0% blocked most of the trip (including at 24 hours drive time), it wasn't until I headed back through Illinois and got stuck in major road construction I say the plugged level climb, which likely is what triggered an active regen while passing through MO. I wonder if the updated fuel pump programing changed the behavior? My truck only seems to now do an active regen based on DPF level not arbitrarily based on time.

I can’t imagine why they would change it just for 19-20… My 18 and 22 have OE CP3’s (or equivalent) and both do 24 hour regens like clockwork.

I’ll be honest, it’s easy to miss… even with the screen up as they don’t last long. I find that far more likely.

I’ve known a couple people who say they have never seen or heard their trucks do a regen, and I’ve witnessed one in both rigs and pointed it out. They just weren’t noticing it, even with visual and aural cues.

 

[Will_T]

I’ll be honest, it’s easy to miss… even with the screen up as they don’t last long. I find that far more likely.

I’ve known a couple people who say they have never seen or heard their trucks do a regen, and I’ve witnessed one in both rigs and pointed it out. They just weren’t noticing it, even with visual and aural cues.

All my regens have lasted at least 10 minutes, but yes if someone is expecting to know when one of these trucks is regening by sound, smell, feel, etc., then I agree it could easily be missed.

If you have the EVIC on the DPF screen, at least on my 2021, it comes up with a big message that it is in regen. I suppose someone could not look down for the 10 or 15 minutes of regen and miss it. In my case, I am pretty sure I did not miss the regens that it skipped because I had both the EVIC screen displaying and my iDash showing the On/Off switch and EFT temps. And because I was intent on seeing it if it happened, I estimate I glanced the evic and iDash every couple of minutes at the most, probably more often. I have not heard of a historical record of regens, so I guess there is no way to be 100% sure that a regen was not missed.

 

[John Jensen]

All my regens have lasted at least 10 minutes, but yes if someone is expecting to know when one of these trucks is regening by sound, smell, feel, etc., then I agree it could easily be missed.

If you have the EVIC on the DPF screen, at least on my 2021, it comes up with a big message that it is in regen. I suppose someone could not look down for the 10 or 15 minutes of regen and miss it. In my case, I am pretty sure I did not miss the regens that it skipped because I had both the EVIC screen displaying and my iDash showing the On/Off switch and EFT temps. And because I was intent on seeing it if it happened, I estimate I glanced the evic and iDash every couple of minutes at the most, probably more often. I have not heard of a historical record of regens, so I guess there is no way to be 100% sure that a regen was not missed.

I'm pretty certain I know 100% of the time. I have set my CTS3 to alarm at 97%, it hasn't missed yet.

 

[AH64ID]

All my regens have lasted at least 10 minutes, but yes if someone is expecting to know when one of these trucks is regening by sound, smell, feel, etc., then I agree it could easily be missed.

If you have the EVIC on the DPF screen, at least on my 2021, it comes up with a big message that it is in regen. I suppose someone could not look down for the 10 or 15 minutes of regen and miss it. In my case, I am pretty sure I did not miss the regens that it skipped because I had both the EVIC screen displaying and my iDash showing the On/Off switch and EFT temps. And because I was intent on seeing it if it happened, I estimate I glanced the evic and iDash every couple of minutes at the most, probably more often. I have not heard of a historical record of regens, so I guess there is no way to be 100% sure that a regen was not missed.

Did you note the hours at which it occurred? If so, watch 24 hours later and see what happens.

 

[Will_T]

Did you note the hours at which it occurred? If so, watch 24 hours later and see what happens.

I do and it did not regen from 120 hours to 170 hours. Then it did as I detailed in post #67. I will be watching to see if it regens again at 194 hours, if not before. Something like one of the dealer visits may have gotten it off track and now hopefully that is over. Although if the DPF readings on the iDash and the EVIC screen were accurate, probably no harm was done going 50 hours without a regen since the DPF was supposedly at or around 0% that whole time.

 

[flan]

I had the CP4 recall done on mine back in Jan but haven’t driven to my next 24 hr interval yet, I’ll keep an eye on it. I always keep the DPF screen up anyway.

 

[Bullwinkle_The_Black_Ram]

That’s how my DPF % works as well during and immediately following an active regen.

If the iDash had more digits you would likely see DPF pressure closer to 0.01 after an active regen.

If my warmef DPF after a 18 mile active regen reads .07 psig @ idle could my dpf sensor be off or possible wrong calibration?

 

[AH64ID]

If my warmef DPF after a 18 mile active regen reads .07 psig @ idle could my dpf sensor be off or possible wrong calibration?

Just depends on the conditions, I’ve seen active regen bring it to 0.01 and I’ve seen it stay up around .07.

With the driving I’ve been doing lately I’m finding that towing and good passive regen is a far better cleaning than an active regen, time or load initiated.

Really goes to show that these systems need to worked.

 

[joshuaeb09]

Just depends on the conditions, I’ve seen active regen bring it to 0.01 and I’ve seen it stay up around .07.

With the driving I’ve been doing lately I’m finding that towing and good passive regen is a far better cleaning than an active regen, time or load initiated.

Really goes to show that these systems need to worked.

I've gotten the lowest readings after all day drives where traffic is moving and you can maintain 85-90MPH for long periods of time (gotta love TX speed limits).

 

[mbarber84]

Awesome thread and great reading. I appreciate all of the contributions.

I’ll add my own experiences from my truck (2022 HO) that I’ve been tracking. It would definitely seem mine is on the 24-25 hour track, aside from when the soot load triggered an active regen faster than the timer. Once completed, mine appears to definitely reset the regeneration timer after each sequence based solely on the data I see. I’m not using any sort of aftermarket monitoring, just the OEM gauge on the evic and the cues I hear from the truck while driving. I will note that I wasn’t previously using hotshots EDT prior to starting this spreadsheet and my soot loading seemed to accumulate faster and passive regeneration didn’t seem to be as frequent or as effective. My truck sees the same routine drive cycles which is a mix of city and highway, with mostly unloaded operating. I took two screen shots of the spreadsheet to make it easier to read, as the whole sheet is wide.

These instances referenced in this thread where there has been a significant amount of time, well in excess of the 24 hour time interval, between regen cycles is concerning. I have operated under the understanding that these systems were designed to actively regenerate every 24 hours as a “fail safe” to ensure the system was routinely “burned out”, especially in situations where the drive cycles alone will not generate the temperatures and length of time necessary to see effective passive regeneration. I wouldn’t imagine why they would want to change the emission control strategy in that manner. To me, the policy of either / or (timer or soot load) gives the best overall protection of the emissions system for a wide range of operational situations. It’ll be interesting to see where this all leads. There have been numerous posts both here and elsewhere regarding DPF ‘s filling prematurely recently. This is especially true of 2022 model year trucks.

 

[AH64ID]

Just today I also verified what I’ve heard about any active regen resetting the 24 hour timer.

My last 24 hour regen was at 293 hours. I then had a DPF soot loading regen at 306 hours. I hit 318 hours today, 25 hours since my last time based regen, and the CTS3 shows I’m only 51% of the way to my next regen.

I spend some time bouncing around 40-45% with some around town drives, but a 90 minute tow down the interstate, and back, out the percentage back at time based.

Maybe the missing sensor has something to do with regen frequency, but I think that most of the comments come from people paying more attention. When looking at use most the frequent regens seem inline with driving style.

As for the missed regens, I’m still inclined to think that the regen was most likely missed. It’s easy to miss, and far more likely than it not occurring.

 

[Will_T]

I do and it did not regen from 120 hours to 170 hours. Then it did as I detailed in post #67. I will be watching to see if it regens again at 194 hours, if not before. Something like one of the dealer visits may have gotten it off track and now hopefully that is over. Although if the DPF readings on the iDash and the EVIC screen were accurate, probably no harm was done going 50 hours without a regen since the DPF was supposedly at or around 0% that whole time.

Another thread reminded me that I needed to update this. The truck indeed did do a regen at 194 hours so it seems back on track. The Banks PID settled down after 45% or so and climbed steadily until it hit 100%. The regen then started. I have put some miles towing on the truck recently and it is now again at the point where it is tracking time. Now at about 70% and climbing to where I expect the next regen at 100% and 24 hours.