Can anyone tell me what makes my 2020 3500 go into regen? I have been kind of trending when it goes in and how long it takes to get out of regen. My regen gauge never goes above half. It seems to regen after 150 miles or so and takes at least twenty miles to clear. If I stop and turn the truck off before regen finishes, does it start over or continue where it was?
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Regen criteria
- Thread starter Big larry
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There are two things that drive active regens.
1) Time, every 24 hours of engine operation will activate an active regen.
2) Soot loading of the DPF. If the DPF gets to ~45% full an an active regen will occur.
Whichever of those two occurs first will trigger an active regen. At completion of the active regen the 24 hour timer will restart.
1) Time, every 24 hours of engine operation will activate an active regen.
2) Soot loading of the DPF. If the DPF gets to ~45% full an an active regen will occur.
Whichever of those two occurs first will trigger an active regen. At completion of the active regen the 24 hour timer will restart.
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What speed were you driving at?
I have found that below 70-75ish without a load the DPF isn't quite hot enough for constant passive regen.
tchur1
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When did you last replace your air filter?
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What filter did you use?
If you’re driving for over an hour and see not appreciable change in the DPC capacity reading, then I would assume you are not sufficiently loading the truck to generate enough heat in the DPF for passive regeneration to occur, while at the same time running the truck efficiently enough that you’re not generating a lot of additional soot. So basically you’ll get a stagnant reading, doesn’t go up, doesn’t go down. It’s pretty hard to achieve passive regeneration on these trucks unless you’re towing or hauling, or unless you’re traveling 70mph or faster. The engine needs a certain amount of load on it in order to get the EGT’s up and heat the DPF adequately for passive regeneration. This is also why the 24 hour time-initiated active regeneration cycles exist. They help to fill in the void between passive regeneration and soot load based active regeneration.
I have not been able to successfully achieve any noticeable passive regeneration in an unloaded state unless I’m traveling at 70-75mph for extended lengths of time, on interstates and turnpikes where climbing some grades is encountered. If you’re a flat lander you’re going to have an even harder time achieving passive regeneration unloaded because the truck is just not working hard enough. That’s why the active regeneration cycles exist. Keep in mind you are generating the least amount of soot when the truck is running at peak efficiency so you still should be able to go a long way on the interstate before the soot loading in the DPF reaches the % capacity trigger for an active regen. (Or the 24 hour timer kicks in. Whichever happens first)
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I have noticed that it takes more work to get the DPF hot on my 22 than it did on my 18. There are multiple ways the tuning is different, but it appears that lower EGT’s are a result of that.
I would agree. I think Ram engineering needs to go back and look at their software and adjust tuning slightly to try and achieve slightly higher EGT’s at around 68-72 mph. Doesn’t have to be much, but enough to get the DPF to regenerate better passively. I know that would have a negative impact on fuel Economy but I think it would be a better approach than loading the DPF continuously and then expecting active regeneration cycles to clean it out. A lot of these people who do not monitor their DPF gauge are interrupting the regen cycles and negatively affecting the DPF health. Yes it will pick up where it left off, but there’s no guarantee the next drive cycle will entail the same conditions or parameters as the one it was in when the cycle initiated.
firemansdiesel
Active Member
I don’t know if I have a unicorn truck compared to some on this forum, or my truck performs as exactly with thousands of other trucks out there. I can achieve passive regens under the 70-75 mph that’s stated. Alot of my driving are ln county roads with speed limits of 55mph. So driving anywhere from 55-65 mph my DPF guage will go down after so many miles with passive regens. Also my truck will do a active regen aroungbthe 24hr mark. With doing the math with engine hours, mileage, 24hr calculation. My truck will do Active Regen every 800-900 miles. That’s unloaded conditions.
What model year ?
firemansdiesel
Active Member
MY2022. Build date of March.
Either it’s a unicorn or you pull enough grades repeatedly to get it hot. My 2022 HO will not passively regenerate much below 70. Local driving it’ll load up fairly quick. When I’m able to throw some towing in during the month, that significantly improves my distance between active regenerations and absolutely works wonders for passive regeneration.
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That could be a difference in SO and HO tuning.
firemansdiesel
Active Member
Most likely.
firemansdiesel
Active Member
No grades at all. I just drive the truck.