I'm new to the 6.7 so I'm still learning as much as I can. I recently added the exhaust filter screen to the display using forscan. I had a regen yesterday. I drove the truck until the exhaust filter displayed 0% full. I've driven about 130 miles today and noticed the exhaust filter is now 50% full. That seems really quick to fill halfway up in so few miles. Is this normal? If not what would cause it? I'm really entertaining the idea of deleting the rocket ship under the truck. Any guidance would be much appreciated

 

Well after reading up on the subject I guess a regen every 250-300 miles seems normal

 

It's within the normal range from what I've seen. Sometimes I only go 100-110 miles in between regens when not towing. A lot depends on quality of fuel. I do notice in the winter with the fuel change I get more miles between them.

 

different things make you produce more soot or less.


Same with the amount of def you use.


In town stop and go makes more soot. Steady hwy will create less.


Towing will use more def about due to hotter exhaust the soot will tend to burn off and not need a regen.


I average about 1 regen a month with the towing I do.

 

I've found like Scott that things can vary. After hauling my 20k RV on a decent trip, I'll stay at 0% full for 200-300 miles. If it's off RV season and I'm just using the truck around town, I find that as soon as a regen is complete, the % starts climbing 5-10% every trip out. I think (as Pocket posted a while back) this is why Ford disabled the screen from the getgo. When the screen is enabled, it allows us enthusiasts to obsess too much about a process that would otherwise be pretty seemless in the background...

 

Karl
You're probably right. Coming from a 6.0, I've been trained and conditioned to monitor everything all the time. I'm coming to realize the 6.7 allows you to just drive without your eyes being glued to the gauges.

 

Tom,

As you mentioned using Forscan. Tonight I went for a 60 mile drive through the hills. Using the lite program on my iPhone, I found multiple DPF variables and monitored each for the duration of the trip. I am trying to determine what is used by Ford to derive the data displayed on th truck screen. Would it be possible for you to monitor some specific values in the PID module and report back with the values in relation to the drop in the in truck screen %?

The values I am capturing are:

DPF_LOAD_PCT
DPF_LOAD_PKUP
DPF_LOAD_CMRL
DPF_SOOT_INF

Two things I found interesting today. First, the pct and cmrl values were pretty close. Both went over 100% but dropped back below 100% by the end of the trip. The pkup variable saw a steady climb, and is only at 41%. Soot went up during the trip srartimg at 2.1 and ended at 2.7.

There are other things that we can capture related to regens including if the last one is was a active or passive, distance since last regen, ave distance between regens, time related to regents, ect. As I have yet to experience my first regen, theses values are not relevant for me yet. I'll work up my resulting into a spreadsheet format as I develop the data.

I'm not sure what can be determined by looking at this information but I think it's a good start to understanding what is going on....for those who are obsessed by it........

 

Carl

I have forscan on my laptop. I don't have anything to monitor vitals while I drive. I do have an old scan gauge 2 but it's loaded up with 6.0 pids. I think I've decided my truck needs to lose some weight and get rid of the dpf

 

No problem Tom. I'd be with you in a heartbeat if I thought I'd keep this one for a long stretch and get around emissions in MD. I've got to believe it would help performance and reliability.

 

Agree.

Rob

 

I have played around with this a fair amount in ForScan. The DPF_LOAD_PKUP description suggests that is the right value for the pickup version, however it is always about half the DPF_LOAD_PCT and never gets above about 50% when a regen occurs. The regen status will go ACTIVE during a regen and say OFF when not. The Passive/Active PID never changes so it is useless. The distance since last regen is accurate, but only updated on a key cycle, not while you drive. The average between regens will update at the end of each regen and is accurate. Mine is sitting at 374 miles right now.

You will see the Soot and PCT increase mostly but it will decrease during a 'passive' regen, when the EGT14 is above 650 or so. On my truck the PCT will get to 110 - 130%, and the Soot to 3.0 - 3.4 g/L or so, then regen will go ACTIVE. The dash display only seems to go up, even when the Soot and PCT are going down. Or it pauses at whatever number its at during the passive regen. I have never seen it go down except during an active regen. When the soot is about 3.0 and the PCT is over 110, a regen is getting close. The dash gage will be at 90 or 95%. When the dash gage rolls to 100%, a regen will start within a minute. The only time this has been delayed for me is when I stopped for lunch just as a regen was beginning. Lunch was at Old Preist Station, it is right at the top of a 10 mile 6% down grade. I started up, the gage still said 100%, but I rolled all the way to the bottom on overrun/exhaust brake and a few miles beyond, before the regen started. So it knew not to start until some load was on the engine for a little while.

On my truck, at completion of a regen, Soot will read around 1.0 g/L and PCT usually less than zero like -5% or so. The dash gage will only go down to 20-30%.

There is no direct relationship between the dash gage and any PID I can find, just a loose correlation. It would be interesting to know how they are calculating that number.

 

Thanks for providing this info. Definitely saved me a lot of time. The quick conclusion I came to was the same as yours above. Their math much come from a set of different monitors.

I beleive some of the values related to load change if there is enough heat generated. The values I observed decreasing yesterday were doing so when I was coming up the mountain. I was not monitoring temps at that time.

There is one variable that I think is the trigger for regen...DPF_REGEN_PCT...it is set to 100% in my PCM and the description says it is a 'normalized' value. There are Particular Matter sensor values and one has a yes no switch for regenerating....I wonder if this comes into play? I would hope they actually use the NO sensors in determining the need for a regen, but who knows.

 

There is also an exhaust back pressure sensor, this value climbs until regen but it is noisy as it depends on RPM and engine load.

DPF_REGEN_PCT might set the trigger, but I'm not sure what they are comparing that to. Mine definitely regens within a minute of the dash gage hitting 100%, but the other values can be in a range. I doubt they would use the NO sensors for regen, those are more for EGR and DEF control. The load in the DPF shouldn't affect NOx, doesn't really affect anything except back pressure.

 

Reading the coffee table book tonight, there is mention of a particulate sensor, pm11, that was added to in my 2015-2016 engines. Going to look at this next run. Also the state regens are related to pressure and passive regen happens when exhaust temp is over 572.