The engine WILL not get stuck in "passive regen" even if the latter is very successful in keeping the soot loading down. That depends on the ability to do long-distance driving at medium load (which means maintaining an average of 800 degrees of DPF temperature). What WILL happen is: The mileage since last regen will reach a certain threshold (seems that in my truck it is about 620 miles) at which point it will start active regen regardless of current loading.

When it comes to "load" versus "soot" creation you HAVE to consider EGR. EGR is the "devil" in this case since when it is most active, it will cause most of the soot (due to managing the combustion chamber temperature). Now, EGR is most active in the "low to mid-range" loading of the engine. At high or maximum load, EGR is comparatively less active.

Frankly, if there was NO EGR, there would be much less need for DPF regeneration.... there ya go...

 

Good point and clarification. Admittedly, I don't know much about how the EGR system operates and when it would cycle.

I am convinced that 9 out of 10 active regen cycles I experience are the mandated ones that will occur at a specified distance or engine hour interval. This is one major reason I wanted to have this motor. My 6.4 would regenerate 3 to 4 times per tank of fuel regardless of my vehicle load and drive style. Drove me mad. This 6.7 is much smarter in the way it handles the DPF. I hope it lasts a long time too.

 

I have 10000 miles on my truck and have never felt a regen. I now have an Edge Insite CST and can view the soot count. Today, during a short regen I guess, the soot count went from 2.80 down to 2.38. The exhaust temps were really high . . . somewhere near 1200 deg f!! That would fry an egg on your engine.

ken

 

So anyone having bought the Edge CST, can you say where and how much? I'm just wondering, may want to get just to learn more about the engines "inards".

 

Minimum advertised price that you will find is $399 with free shipping. They can be found for less if you check around. The main reason I bought mine is to further understand what is going on with regen. The truck always goes into regen at the most inconvenient time (within a mile of my destination) and the CTS will allow me to see how complete the filter cleaning was and help me know when to expect a filter cleaning.

 

Is the correct part # for insight cts.83830. for 2011 superduty 6.7 ?

 

It is an expensive gadget and in my case, I didn't "need" it because I don't tow heavy or in the mountains.
However, I prefer to monitor things so I purchased one as a "want."
I do find it useful for planning regens though.
2.66 soot GPL and it will start soon after.
Active regens are something else we don't need to worry much about but if I can allow one to complete fully, I feel better about it.

 

My vendor just informed me that an update for the CTS in the near future will include PIDs for Rail Pressure and Exhaust Back Pressure. He also told me if there was anything else I wanted to add that he could get it taken care of. I have a request or two, I'll let you know how it works out.

 

Exhaust temps around 1200 degrees - you are definitively talking active regen. I don't recall EVER seeing temps that high without active regen.

However, I am concerned about the fact that the soot count only dropped to about 2.38 -- and the regen completed? That is clearly not what it should be doing. It should drop way below 2.0.

 

This is good news.

 

I have noticed my active regens are less than 200 miles. I have a 25 mile commute to/from work and there are times the regen wants to happen right before I get to work or right before I get home so it doesn't have time to complete. Usually the second drive from that point kicks on another active regen to catch back up to what didn't complete before. If I get a decent distance driven while in regen mode then I get under 200 miles between them.

 

Unfortunately it takes a while for the ECM to command regen after starting the engine cold. I noticed that if the conditions for a regen are met and even if the engine temperatures reached normal conditions, it waits for some additional time before it engages the regen. Did you ever have the "wrench" come on or even the CEL and Wrench come on as well as the "drive to clean...."?

This actually happened to me this morning. I wanted to head out to camp and after a couple of miles the soot count jumped from 2.2 to a wopping 6.5 going up and up! The CEL comes on around 6.0 and the Wrench comes on around 4.5 and of course with the CEL there is also reduced power. What a mess. It would not turn on regen even under those circumstances until I drove an additional 10 miles!! Then, it finally turned on regen and brought the soot count down to about 1.7 where it turned off telling me that it completed and the CEL turned off. I am wondering about the sudden jump of the soot count from relatively normal to beyond a CEL condition! I wonder if there is an issue with the DPF pressure sensor or something along those lines...

 

I can't believe what I found today after looking for a reason why my engine is not performing as well as it used to for several thousand miles:

I've been researching issues and possible reasons for low-rpm power sluggishness and issues with DPF/regen efficiency and frequency. Maybe a noticeable amount of fuel-mileage loss too. These are the symptoms I had:
1) low RPM power sluggishness - example: if you need to lightly accelerate while the engine is running around 1200 RPM - no effect, not until you push hard enough for the downshift to occur which ends up shifting 2 gears down before anything happens.
2) low or little effective passive regeneration capability resulting in higher average DPF soot accumulation levels than before and more frequent regens.
3) Overall power loss to some degree - maybe less noticeable at full throttle and high RPM.
4) slower acceleration: Mostly noticeable due to an apparent power loss (sluggishness) right after an up-shift.
5) erratic soot-accumulation count behavior resulting in outrageous values to occur suddenly. For example: This morning I took off with a soot value of 2.2 and cold engine. After a few miles, all of a sudden the soot value stood at over 6.5!! and the wrench and CEL lights came on with "Low Engine Power" etc... While this situation was worse than any I've seen before, I did notice an occasional erratic "jump" in soot value and an extended hesitation for the ECM to command active regen.
6) I noticed over the recent past after idling for a while that there was a smell of diesel exhaust in the cabin... hmmm!

Here's the reason for all this: The turbo exhaust exit downpipe houses the pickup plumbing for the exhaust pressure sensor. The fitting nut (5/8 wrench size) tends to get loose and in my case was completely UN-DONE literally off the thread! (my engine was built in July 2010) Needless to say, you can see a bunch of soot accumulation over the nut/fitting etc. Of course, this will cause not only erratic exhaust pressure readings but most likely readings that are much lower (or even zero) than they should be. Looking at the logic and math driving the EGR, exhaust pressure is one of the key parameters as it is used to determine the EGR valve setting in relation to the intake/turbo pressure. The Exhaust pressure ALWAYS has to exceed the MAP pressure by some amount. If not, the ECM is closing the throttle on the intake (independent of your gas pedal position). Now, if the EP is signaling too low (which would be the case with the leak), the ECM will throttle the intake and in consequence OVER-EGR the combustion resulting in excessive soot and lower performance. Of course more soot (even and especially at very light accelerator) defeats passive regen and shortens the active regen cycle. There are more related issues around this, but those are the most obvious.

So, I recommend for any of you that have some concerns about how their truck is running to check that fitting. Unfortunately it is very hard to reach: 1 way is from below (passenger side rear of engine) - but you need a very long arm and tool to extend it. But at least you can check if is loose in one or another way. You can also see if it leaks by checking for soot accumulation on the fitting.
You can see the fitting from above peeking past the intake (HP) and EGR plumbing (passenger side) but there is no way to get a hand/arm/wrench into position from there.

Finally, the best way to get at it is to remove the passenger side front wheel, remove the flexible splash cover and get to it by reaching past the left side of the front right suspension from the wheel well.

Even though this may sound like hard to do or much work - I believe if you have any of these symptoms - go for it!

 

Okay. Thanks for the info. I will monitor the soot count vs regen, and check the gas temps.

ken

 

Wow! That is some good investigation work you've done there.

I hope it fixes your problem. Report back to us when able to verify that you fixed it.