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Discussion Starter · #1 ·
Hi Folks, I've searched the forums and found different people with frequent regen problems, but never really found an answer to the problem. My 2016 has started doing regens every couple hundred miles. Truck is all stock, but I have a CTS2 monitor so I can tell when it is going into regen. For the first 4 years or so it was every 1000 miles. My driving habits really haven't changed. The truck only has 42000 on it, so it isn't worked hard, which I know doesn't help with the problem. There have been no codes thrown. I pulled the differential pressure sensor and everything looks clean. I have a hard time believing it's the scr since this change didn't seem to happen gradually, but was all at once. Do the differential pressure sensors go bad? Does anyone have any suggestions where else to look for the issue? The tailpipe is as clean as when it was new, if that helps any. It wouldn't be a big deal, but it's killing the fuel mileage. Much appreciated for any advice.
 

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Hi Folks, I've searched the forums and found different people with frequent regen problems, but never really found an answer to the problem. My 2016 has started doing regens every couple hundred miles. Truck is all stock, but I have a CTS2 monitor so I can tell when it is going into regen. For the first 4 years or so it was every 1000 miles. My driving habits really haven't changed. The truck only has 42000 on it, so it isn't worked hard, which I know doesn't help with the problem. There have been no codes thrown. I pulled the differential pressure sensor and everything looks clean. I have a hard time believing it's the scr since this change didn't seem to happen gradually, but was all at once. Do the differential pressure sensors go bad? Does anyone have any suggestions where else to look for the issue? The tailpipe is as clean as when it was new, if that helps any. It wouldn't be a big deal, but it's killing the fuel mileage. Much appreciated for any advice.
I can’t help you too much with fixing the problem, but my 2013 did the same thing around 55k. All of the sudden it was in regen every two days, and my average mileage which was always at 16.5-17 was now at 12.5-13. Back then I came up with another solution, which we won’t discuss here.
 

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Does the truck complete the regens everytime? Decent chance it just needs worked hard. What are your normal driving habits, mostly town or highway?
 

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Does the truck complete the regens everytime? Decent chance it just needs worked hard. What are your normal driving habits, mostly town or highway?
I thought the same thing about my 2013, what really made me mad is that the morning after I did 4 hours highway it still was stuck in regen. I also feel this Chevy regens more than it should for pulling 15k as often as it does.
 

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Discussion Starter · #5 ·
Does the truck complete the regens everytime? Decent chance it just needs worked hard. What are your normal driving habits, mostly town or highway?
Yes, I assume it completes the regen almost every time. I try to keep driving till it stops on its own most times. It’s a fair amount of around town driving. I did a 4 hour trip with a trailer and worked it harder not too long ago and that seemed to help for a bit, but then it went right back to how it was. My driving habits haven’t really changed from when it was doing regens every 1000 miles - so that’s why I’m puzzled. I’ve never gotten a dash warning that the dpf is 80% full or anything like that - but not sure the newer trucks do that anyways. The lines to the sensor aren’t carboned up at all. I think I may pull the egr valve and clean it and make sure it‘s not sticking or something. Thx for the input.
 

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Pulling a light trailer or highway drives dont always get the trucks working.

Check all the intake sensors maybe one needs a cleaning. .
 

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Have you changed where you purchase fuel or are you using any different fuel additives? Also, has the truck been to the dealer where perhaps the software was updated?

I have a 2017 that I daily drive and it averages a regen every 200 miles, but it always has(I realize yours used to have longer intervals). The only time I ever made it close to 1000 miles was pulling a trailer on the highway with EGT’s around 850. Even with my frequent regens my fuel mileage doesn’t seem to really take a hit. Still average around 16 with mostly in town driving. I also do oil analysis and no fuel dilution has ever been noted.
 

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Discussion Starter · #9 ·
Have you changed where you purchase fuel or are you using any different fuel additives? Also, has the truck been to the dealer where perhaps the software was updated?

I have a 2017 that I daily drive and it averages a regen every 200 miles, but it always has(I realize yours used to have longer intervals). The only time I ever made it close to 1000 miles was pulling a trailer on the highway with EGT’s around 850. Even with my frequent regens my fuel mileage doesn’t seem to really take a hit. Still average around 16 with mostly in town driving. I also do oil analysis and no fuel dilution has ever been noted.
Thanks. Fuel pretty much always comes from high volume stations and the truck has never been to the dealer. No additives. 16-17 is what I average now, too. But that’s down a couple due to the frequent regens. It was 18-19 around town (manual transmission).
 

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Have you removed and cleaned your MAP sensor on your intake horn? They tend to really get sooted up and can effect engine performance.
 

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Discussion Starter · #11 ·

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One more long shot. Pull your DEF injector and check/clean the tip. Before I get chastised, I understand from the knowledge gained on this site that DEF is injected into the SCR and doesn’t have anything directly to do with the DPF and regens. However, here is my theory that could very well be wrong.

If not enough or potentially even poor quality DEF is being injected the computer will sense high NOx. Not 100% sure if the system works this way but if the NOx is too high and can’t be lowered by the SCR, it may command more EGR and thus more soot and more regens.

Also just curious, are your posted MPGs hand calculated or from the truck EVIC.
 

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Discussion Starter · #13 ·
One more long shot. Pull your DEF injector and check/clean the tip. Before I get chastised, I understand from the knowledge gained on this site that DEF is injected into the SCR and doesn’t have anything directly to do with the DPF and regens. However, here is my theory that could very well be wrong.

If not enough or potentially even poor quality DEF is being injected the computer will sense high NOx. Not 100% sure if the system works this way but if the NOx is too high and can’t be lowered by the SCR, it may command more EGR and thus more soot and more regens.

Also just curious, are your posted MPGs hand calculated or from the truck EVIC.
I’ll check the def injector - it‘s worth a shot. I hand calculate the mileage.
 

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One more long shot. Pull your DEF injector and check/clean the tip. Before I get chastised, I understand from the knowledge gained on this site that DEF is injected into the SCR and doesn’t have anything directly to do with the DPF and regens. However, here is my theory that could very well be wrong.

If not enough or potentially even poor quality DEF is being injected the computer will sense high NOx. Not 100% sure if the system works this way but if the NOx is too high and can’t be lowered by the SCR, it may command more EGR and thus more soot and more regens.

Also just curious, are your posted MPGs hand calculated or from the truck EVIC.
Those who may chastise may not be familiar with all the different styles of emissions systems there are. One example I've been involved with has a DOC, DPF, and SCR, however the DEF fluid is injected before the DPF and after the DOC.
 

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No, the DEF is always injected in front of the SCR to help with the chemical reaction to changes nitrogen oxide to an inert gas.
No you are wrong. I have small Caterpillar excavators with DEF injected before the DPF.
 

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SCR is after the DPF (usually) DPF is usually right off the engine -

I have gotten two notifications in the last 3000 miles (21k on truck now) that DPF was 80% full and it took about 10 mins of driving to complete regen - its a 99% unloaded, pavement princess with probably 70% highway driving -
 

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2011 Ram 2500 4x4 6.7 68RFE 4 inch lift
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On my 11’, there’s no SCR, it’s CAT, NOX then DPF. So 13’ and up its CAT, SCR then DPF??
 
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