(Provided that a soot-triggered active regeneration didn’t happen in that 24 hour period)
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Passive Regen
- Thread starter CdnHO
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I thought that number seemed implausibly high as well. The cycles are easy to miss
He’s calculating your average speed based on the 24 hours between regenerations and the 1,700 miles. Which is the correct way to gauge what types of drive cycles the truck sees. Total operational hours count towards the regen timer, this includes idle time and low speed driving. Towing is irrelevant. It’s practically impossible to get a truck up to an average speed of 70mph. Mine sees mostly highway driving and regenerates every 24 hours on the engine which usually is about 900 miles traveled. That makes my average speed around 37-38mph.
I’m certainly no dummy but you guys have me totally confused. Is there a document somewhere that explains the protocol used to determine regens? All I know is I kept the DPF screen up the entire trip which probably took over 30 hours and included five overnight stops. Trailer weighs 22K pounds. Did not see a regen message.
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Active regens are initiated two different ways.
1) Time. Once any active regen completes a 24 hour run time clock starts. That’s engine run time, idle or driving. When you hit 24 hours since the last active regen an active regen will occur, even if the DPF is soot free from towing for the last 1000+ miles. This type of active regen can be very short if you have been towing, and are towing when it occurs.
2) Soot loading. If the DPF is accumulating soot the EVIC DPF gauge will indicate the DPF is filling up. At approx 45% full on the DPF gauge the truck will initiate an active regen. This type of regen is typically much longer as there is more soot to burn out.
Both of those will get the same message on the EVIC DPF gauge, “Automatic Exhaust System Regeneration In Progress”
There unfortunately isn’t an official document on this generation of truck.
Since your trip took 30 hours you had a time initiated active regen during the trip and missed the message. It’s unlikely that you had any soot load based regens since you were towing and had adequate passive regen. The time based active regen could have taken as little as 10 minutes if it initiated while you were towing and the exhaust was already hot.
Spot. On.
Adding to this: I have noted at all of my 24 hour regeneration cycles are pretty much spot-on 20 mins. I’m usually unloaded, at highway speed 70-75 consistently. They’re usually right at 20 minutes give or take. The discrepancy in a minute or two is, I believe, merely a factor of “when” I notice the regen start. I might be behind a few seconds from bouncing back and forth between the DPF gauge and the digital speedometer. I have never had a regen start while towing so I can’t speak to that part. Usually, just by sheer coincidence, I am never at a point where a regen is possible when it’s time for me to tow. And obviously, if I start out with any soot accumulated, it’s gone quickly once the trailer and truck are rolling.
CdnHo is not the only one to go on an extended road trip (mine 3200 miles) and observe extended periods with no active regens. My 19 HO (post fuel pump recall reprogram) went 32 hours without displaying it was performing an active regen and I was watching for it the whole drive. Passive appeared sufficient to keep the DPF at or near 0, and only when I saw the gauge climb to 50% did I see it go into an active regen. I was driving in a rain stom that kept my speeds low (45) that saw the DPF plug up and trigger an active regen.
Active regens are generally noticeable on my truck The engine idles rougher and sounds different while driving and I often find they take 20-40 minutes to complete. With the vibration and sound cue's its usually hard to miss when the ECU is executing an active regen. Never had a quick regen, that I've caught.
On the 3200 mile trip did I stay above 70 the whole trip? no, lots of in town miles at the destinations. I was above 70 while on the interstates when traffic would allow generally 85 (max cruise would set to). I too have observed the truck has to be under enough load that passive regening was sufficent keep the DPF clear at 0%
The new airfilter from WIX i'm seeing active regens now about every 300-600 miles (much shorter than before). My observation is; I've never seen the ECU code that dictates the logic of when active regens occur and what sensor thresholds may trigger it so I can only report observations. Maybe the there is another type of active Regen that these trucks can undergo that trucks don't report on the driver display as an active Regen? Maybe there is variability on the software logic/displays between years, SO/HO/Cab and Chassis? If it was sold in a Carb state or not...
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One other quick thing, I'm not the original owner of my truck. It had some modifications the dealer removed (undisclosed) and I also removed to return it to stock. I believe the emissions components are fully stock and intact and I'm running the stock tune, especially since I had the CP4 fuel pump recall and reflash. I will admit it is possible that the previous owners tampered with the emissions and tuning that I haven't yet discovered. I also have never driven another 19+ Ram 3500 HO to compare mine with to see if it performs differently.