Odd engine time

[joace]

Since my 22 3500 is also observed with frequent regen, so I started from this March to track the regen data, but today saw a very odd entry, my last regen recorded on 10/29 with below hours, today had another one, but the engine run hour is the same, only has 3 hours increase on idle, definitely this is not correct, I couldn't drive 300 miles without engine running, is there anybody happen to see the similar issue?

Number	Date	Time	Start Odo	Start DPFRG %	Engine Total Hour	Engine Run Hour	Engine Idle Hour	Finish Odo	Finish DPFRG%	Miles to Regen
17​	10/29/2023​	6:30PM	12327​	100%​	481​	358​	123​	12353​	18%​	224​
18​	11/13/2023​	8:12AM	12655​	100%​	484​	358​	126​			302​

BTW, this is just the 1st time happening, I drove a lot DD in city, only a few weeks or a month to pull 5th wheel, I understand I can't expect high miles intervals between regens.

 

[AH64ID]

Is it possible that you entered the previous run hours wrong?

I see you track start DPFRG%, have you ever seen it start any anything other than 100%?

 

[joace]

Is it possible that you entered the previous run hours wrong?

I see you track start DPFRG%, have you ever seen it start any anything other than 100%?

I think I didn't enter the wrong number, as I always take a photo of engine hour dash screen when regen starts, so I can update my tracking list with current data when not driving.

I have a banks idash, DPFRG% is one of gauges I set to monitor, every time it only reaches 100%, regen will start, observed from dash's DPF screen and another idash gauge indicator.

I will continue to monitor to see whether it persists or just one-time occurrence, but from over half year tracking, and DPFRG% number changes in a non-leaner way, e.g.,

1. after regen completes, it normally reset to 18% ~ 20%, but will quickly climb to 40% within a few miles, under the same driving conditions, it can stay a litter longer before 60%, after 80%, it runs fast again;
2. I observed that if I drive on highway at 6 speed and 75mph without loading, the DPFRG% increase very quickly, my understanding is that if engine works hard, it can burn more soot, so supposedly % should increase slower or even decrease, so far still no idea why this happened.

My next step is to check i have any intake leak, and try different fuel stations, stop hotshot EDT.

 

[AH64ID]

Do you still have the photo? Deleted photos are often stored in the deleted folder for 30 days after deleting.

Yes regen percent is a standard PID that most OBDII readers should be able to read, I watch it on my CTS3. Since you record the percent at which it starts I wondered if you had seen something other than a regen starting at 100%.

Time is linear, soot loading is not. Both are reported thru that PID adn the display is whichever is higher.

Odd on the rapid increase at 75 mph, what kind of mpg's are you getting at that speed?

 

[joace]

unfortunately i cleaned up deleted photos at every end of month, I should have to keep them longer.

From my tracking, never seen a regen before 100%, not sure how RAM calculate PID % number, but seems they have a complicated algorithm to factor multiple readings with the current driving conditions.

I haven't tried to check the whole highway trip MPG at the speed 70~75mph, but I enabled the real time mgp reading on my dash, not sure how accurate it is, but driving at 70mph, i could see the number around 22

 

[AH64ID]

What I have seen is that at 22+ mpg there isn't any passive regen, 18-22 mpg is more of a net neutral, and anything less than 18 mpg will have continuous passive regen. Below 12 mpg and you're cleaning it fairly quickly.

I have found that normally the regen % goes to 15 or less (seen below 10% a few times now), but it depends on how quick I stop after the regen. It usually goes to 30-40% until I restart the engine. It will jump around to 45-55% the first 12 hours after a regen. That's the various soot loading driving the %. I rarely see anything on the DPF gauge the first 12 hours following a regen, but then if my driving style is around town the % and DPF gauge will show increased soot. I have found the soot loading jumps the most on a cold motor, cold DPF, low rpms, with a load. If I get the temp built up in the exhaust and get the rpms up occasionally the % doesn't climb as fast and will often drop a little. I'm still monitoring it and learning.

 

[joace]

Yeh, that's what I'm thinking, just cruising at a higher speed without a real load, may not help on passive regen, i could confirm that if I tow my 5th wheel, the DPFRG% definitely would go down, without triggering a regen. Instead, engine would burn more fuel and air at that condition, so generate more soot, just my personal theory

Thanks for sharing your experience! Like I mentioned, I DD a lot in the city, so don't expect higher miles between regens, probably around 400~ 500 miles is my hope, but as long as it works as expected when towing, and really clear the soot with every regen, I'm fine with it. Driving this diesel truck forces me keep learning a lot new stuff, and refreshing my knowledge.