Unsuccessful regen?
Like a lot of you I enabled the DPF % screen with FORscan. I have been watching it a lot trying to learn more about the regen logic.
We loaded up the camper and headed out from Rainier OR to Leavenworth wa with the DPF at 70%. I watched as it slowly got to 90% just after we crested Snoqualmie pass.
The truck started to get REAL bad MPG, like about 5 mpg, and we where going down hill with no throttle. this went on for about 15 to 20 minutes. The DPF% went from 90 to 95 then my MPGs returned back to normal.
Continued driving but mostly down hill or flat. the % final hit 100, but still no sign of regen, and we started climbing the last hills till we got to Leavenworth.
Finally the DPF% went to 95, and then continued on down to about 85%, by then we had crested the last summit and where on the way back down the hill.
I was worried that with no throttle input I would loose the regen but it continued down all the way to 0%.
The only thing I can think that happened the first regen attempt is the truck tried to go into regen just AFTER we crested Snoqualmie pas the exhaust cooled to quickly and with the long down hill run the exhaust just couldn't get hot enough to light off the extra fuel. The second time the exhaust was already at temp so the extra fuel easily burned, even with no throttle.
Its probably a one time thing where the timing of everything was such that the regen failed, if that is what happened.
I can see why Ford doesn't include the screen as standard on most trucks, it does cause some unnecessary stress when you see 100% and wonder why you haven't started Regen, and you cant do anything about it anyway.
The Edge CTS for example shows a small red circle at the top indicating when the PCM is commanding active regeneration, which on the 2011 is commanded 30 seconds before the brief screen is shown on the instrument cluster.
As for active regens, the extra fuel dumped into the exhaust causes EGTs to rise or stay at high levels even when coasting downhill so the regen continues.
Until last week, I've never had a regen last more that 30 miles and had one as low as 12 miles once. While towing my 10K fiver home last week, I had a regen last for 38 miles!









