I was driving stop and go traffic. My DPF hit 99%. Within 4 minutes it plummeted to 10% in stop and go traffic. That was much quicker than at highway speeds (15-20 minutes). My question is does the DPF filter ever show 0%? Thanks.

 

mine always goes to zero after reaching 100% (full).

lots of people report that theres does not. So some do, some don't.

 

 

Watched mine last night go from 95 to 55 in the span of 10 minutes or so and stopped there. I'm just under 6k miles and from I read the system is programmed to Regen every 500 miles on the nose so something is off as it appears mine did at least a partial Regen based on the percentage. It's all new to me and I'm learning. It is fascinating for sure. I did learn that when the def tank shows 1/4 tank it will hold just over 5 gallons of def fluid not the 7.5 which would be 3/4 of the 10 gallon tank so there is obviously a reserve built into it as well.

 

A few items. It will regen 500 miles from the last regen, not every 500 miles on the nose. A regen can also be triggered by the DPF load reaching 100%, of the grams per liter reaching 8.38. The regen will continue until finished as long as you are driving and the average speed stays above 35 (whatever that means). If you take the truck out of 'drive', or are stationary for too long, the regen process will be stopped.

The DEF tank is only 7.5 gallons, not 10, so from 1/4, 5 gallons will come very close to topping it off.

 

 

You can stop (such as at a traffic light) while it is in regen, and it will continue, but if it is a long light, or it take multiple cycles of the light, before you get back above 35.....

As for partial regens, it does not hurt anything directly. Say you hit the 100% DPF load trigger, but are a few minutes from your destination. The distance till next regen resets to 500. the Gram per Liter is where ever it burned down to, as is the DPF load. What it leads to, is you might had another regen kick off in a mere 25-50 miles. Repeated long term cycles of interrupted regens may not be good, but in here and there will not hurt anything.

The bigger issue I have with the interrupted regens, is that I have a CTS monitor, and can look at EGT's. There is just something disconcerting about shutting the truck off, when the temp at the turbo is 900, or at the DPF is 1150. I typically put the truck in park, and let it idle for a few minutes for them to come down.

 

I pulled out of a walmart, sat at light. pulled away about 20 mph and stopped at light 1/4 mile up road and watched the def filter plummet. Mine did not follow the 35mph rule. It was very very fast no more than 4 minutes. I kept driving stop and go for another 10 minutes and it never went below 10%. I did see the paint on the car next to me blister, lol!!!

 

The DPF regens much faster when it can retain heat ... r​egens complete faster when the heat is not dissipated quickly as is the case when travelling at highway speeds.

I have to take exception with that statement. A few times I have stopped at a store in the middle of a regen and restarted my truck with the remote right after exiting and locking it ... just left it idling while shopping (I do have "Secure Idle" enabled thanks to Forscan mods). Every time, the DPF% gauge indicated a 30 to 40 point drop when I got back in my truck (less than 15 minutes after restarting).

EDIT TO ADD: The times I've left the truck idling, the DPF% continued to drop on my ride home until it reached 0%.

 

Using the Edge CTS to monitor the PID for the regen process, it shows the active regen being stopped within about 30 seconds of putting the truck in park. It has done this every time I have reached my destination while it was in a regen. That said, while traveling down the highway, the active regen is often stopped while the filter is still at 25-30%, and will continue to burn down to the 10-15% range, the filter is still hot, and the deposits continue to burn for some time after it stops dumping fuel into it.

 

 

I used to get a kick out of setting the dash up on my 2011 Ford F250 to watch the fuel usage during regens. It always told me that the mpg during the regens was dropped from normal to around 2 or 3 mpg during the regen.
But what sucked even more than that was when my truck started losing mileage very rapidly for no apparent reason. It started out getting near 20 mpg light truck on highway cruise on, but steadily kept dropping until at one point it was down near 11 mpg and getting worse. Ford engineers could not figure out why it was doing that. Finally I just sold the car to a car flipper place because it was killing me on fuel usage. Finally read somewhere that it may have been due to the transport line from the DEF tank to the inject point on the monstrosity of an exhaust system getting crushed during shipping (which seems like a real stretch to me but whatever). Supposedly the NOx sensors upstream and downstream of the inject point [selective catalytic regeneration or SCR] were not seeing a satisfactory reduction of oxides of nitrogen so then the computer would radically alter the fueling to the engine which would then greatly increase fuel usage. Combined with the regens of the DPF every 4 or 500 miles, well the bill for feeding the beast just got unbearable and I had to get rid of the POS. I do not intend to ever buy another modern diesel with the infestation of emissions crap that ruins these otherwise fine trucks.

Thankfully there is a 6.2 gasser available.