2011 F 350, 20k Miles

ole truck gets about mid 13's day in day out, that is combo of city/hwy. Get out on the hwy and I drive around 62-65 mph unless I am running late. I can break 20 mpg, but it will drop like a rock the min I get off interstate, but I can expect 16's going cross country.

Got a load, camper weighs in at 5500 lbs and I can get mid 13's on hwy no problem, same speed.

So the other day I get a letter from FOMOCO telling me I had do so some kind of a upgrade to sumptin for whatever reason, forgot, everyone else got same letter. I take in they flash the 'puter and mpg drops like a lead balloon, I cannot even hit mid 11's on the hwy, around town its in the 9's...WTF. Stop by 2 Ford dealerships and they can shed no light, but one says bring in and leave it about a week and maybe we can find something. OK, but wife is out of town and I will do it when she gets back.

About 6 weeks pass of this and every time I fill tank I want to shoot the truck. I was used to seeing miles to empty around 490-510, now its 370-390 and diesel is not cheap even here in Texas.

So I am planning on taking it, wife is back and she can drop me off, will do it next week. I fill and by chance I look down at my puter on the way to San Antonio and WHOA, its 15.9 mpg, huh, have not seen that in nearly 2 mo.

Will that has been a month ago and my city/hwy is now mid 14's. Have not made a hwy trip but expect it to be in the 16's...

My driving habits have not changed, leave the ranch, head into Wal Mart, Tractor Store, maybe stop at HEB (its on the way out) and head back home, plus my weekly trip into San Antonio same place.


Guess its all good, but strange...any thoughts.

 

regen....you were perhaps not letting it complete.

 

explain on that (my first Ford)...

 

I'm going to agree with Scott. Probably a Regen. I'm wondering if the truck automatically went into Regen at first full operating temp after the flash since the computer might have lost track of whatever calculations it's doing to determine how often it regens.

 

newer diesels have a DPF or particulate filter to trap soot. Once the dpf is full then it goes thru a cleaning cycle.

Cycle is done by sending raw fuel into the exhaust to the dpf. Super heats the dpf and burns the soot.

If the cycle is not allowed to complete..it just starts again and again till it gets er done.

May or may not be your case but it sure sounds like it.

 

Every once in a while I get that message on the dash, it comes on and rarely stays on much more than about 30 sec max. Seems to come on very randomly, might not see it for 3 weeks then 2 x in the same week.

 

message is brief...but it is not completed..On my 6.4 it takes 8-10 miles to complete.

Not sure on the 6.7 how long it would take.

 

I have wondered about that as it only on a few sec and then off only to return weeks later sometimes. I was under the impression you should not turn off the engine while it doing its thing, but??????

 

But you have to know it is complete...hard to see that in the crystal ball. Have to cycle thru your system messages. Should be one in there that will indicate if it is still cleaning or not.

Or

Get something that will monitor it for you. Something aftermarket that will should you engine temps and dpf status.

Shutting it down while in regen is hard on it. but if you let it idle a couple of minutes in park it should be ok. Putting it in park should cancel the cleaning cycle. Letting it idle will bring the temps down and help to ensure that fuel in the cylinders gets burn rather then seep into the crankcase

 

Next time it happens I see if I can find some system messages...this begs the question...how often should this take place??? I mean its seems to be a rare thing.

 

I had surgery a few weeks ago so I've only made short trips around town lately. My MPG dropped from mid 17 to 20 highway to 11 to 14. Every time I fire up the truck I see a regen message. So I did make one 200 mile round trip and after that I'm still showing mid 14.

I suspect I'm going to see this until I return to work doing a 50 mile round trip daily. Also note that I'm probably using winter blend fuel at this point so I should be using PM-22 now.

 

It varies on your driving habits. If I'm snowboarding a lot (220 miles, highway speeds uphill, etc) it rarely happens. If i'm spending most of my tanks driving kids to school around town doing no more than 35 mph, then it happens more often. diesels aren't as efficient in city driving, so they soot more and therefore the DPF fills up faster.

When the system thinks the DPF is full, it leaves the driver's side bank (left side, i'm assuming from drivers position) of injectors open during the exhaust cycle allowing unburnt fuel to travel to the DPF and incinerate in the filter, causing a cleaning cycle. I'm told you can hear the difference in the exhaust, however I've not been able to notice yet. This would explain the large drop in fuel efficiency.

If I get a cleaning filter message on the console and I am able, I try to hit the interstate for about 10 minutes and let the needful properly happen...when I can.