2 fewer cylinders at nearly the same displacement isn't a good excuse for better fuel economy.

It is true the US07 engines will most likely not get the same fuel ecomomy their predecessors did simply because of the addition of the DPF. The engine management system is now operating on a high NOX/low soot mode where previous engines were just the opposite. This is accomplished via injection timing, DST and EGR control. The DPF also adds a certain amount of back pressure that must be compensated for. Then active regeneration uses a small amount of fuel as well. I'm not familiar with the regen frequency of the 6.4 or if it even utilizes passive regeneration. Some how I doubt it. I still find it hard to swallow the seemingly huge difference in MPG versus the 6.0L. It will be interesting to find out what the Cummins will get. Afterall, it already meets the US10 EPA regulations.

 

30 towing, I'm going to have to say BS to that, unless its downhill the whole way. (which its not. lol)

I will say the 18 in the dmax is very possible. Our lifted 05 got 18mpg highway (70 or so mph with 36" tires). My C5500 4x4 at best got 8.5 unloaded (12k lbs empty).

 

Yeah thats true...Hmmm I used to have a '89 2.9L v6 Ranger that only got about 11 mpg on a trip from AZ to MT and my 4.6L v8 2005 Mustang GT got 33 mpg on the same roadtrip, go figure.

 

Well I took my truck to Mossy Ford for the recall today and the diesel mecanic there and there is only one reprogamed my truck and answered two questions for me the first is on the noise that I experienced coming out of the turbo is due to the cooling system of the turbo charger when it gets too hot and the segond question regarding my speed drop twice to 40mph during climb is due to the truck computer sending or going to regeneration because while it does go in to that mode the engine cuts out its output by half. He said that when the computer sends the truck in to regeneration mode it does just what I experienced with it and most likely it did it while the engine was being pushed hard climbing the hill.
and to make matter worse now the reprogaming is suppose to even turn the power of the engine off and leaves you only with braking and steering power and tells you to pull to the side of the road and wait for it to finish its job and recycle after that you need to turn off the engine and turn it back on hoping the check engine light went off and if it did then you can drive and if it did not call for help as the truck will not be able to be driving.
have you guys read the little card that come with the recall letter and you are suppose to keep it in the glove box based on there recomendation.
after reading it I really feel now that I got robed by Ford.
what it means is drive at your own risk after I took 63k from you oh by the way if you got in to this mode thing and the check engine light come on pull to the side of the road and call the dealer for help you and toyhauler full of toys and tell the kids that there vacation is over now and the wife that you are sorry you bought a ford and wait until two towtrucks come to get you with fifth wheel and by the way you need to pay for the towing of the fiver because Ford will not pay for it.
this Ford F250 ownership is starting to become a nightmare seriously did you guys read the card with recall letter read it and comment I am french so my english is not lawyer standard but that is what I understood.

 

I doubt you went into a regeneration mode while pulling the grade. You had so much heat going through your system pulling 15,000 lbs up the mountain that you were making enough heat on your own to clean the DPF. Regen only happens when there is not enough heat from the engine to burn off the particulates trapped in the filer.

I think the your Mossy tech is just too green when it comes to the 6.4, that he was only guessing as to why you dropped to 40. I'm still guessing that with 15,000 lbs and a 3.73 on a 6% grade is the reason you slowed down.

 

Passive regeneration does occur, but is it accounted for by the EMS? If not, then he could have been in a regen cycle, but the excuse his tech gave him that is derates the engine by 50% during this cycle defeats the whole purpose. The engine needs to produce heat in order for the catalyst to get hot enough to burn the fuel being injected into it. By derating the engine, the natural heat from combustion is lost, therefore, regeneration can't take place.

I agree that the truck was most likely overloaded. Also, they may have some altitude derate strategies in place to protect the DST from overspeed. What was the altitude where you climbed this mountain?

 

I heard that the engine will drop to 325 hp when in regen. It will not drop in half like your tech stated. I hope you never experience this limp mode they have programmed in.

 

What is the redline on the 6.4? You have to be close at 75 mph with 4.88 gears.

 

Tach goes to 5K, no redlines. 55 mph is about 2000rpm and 80 is about 3000rpm

 

The new Super Duty should have been a 6cyl also...


QUOTE=jvoigt]The dodge gets better MPG cause its a 6 cyl, but still I was hopeing that the new 6.4 would get better but then its still less than 4 months since people started posting there mpg and who knows what will turn up.[/QUOTE]

 

lets assume that your guess is right then why the LOW MPG and how to resolve the issue change the 3.73 with 4.10 what will that do to the truck and does it affect the way it drives? is it more rougher ride? and also will it improve the low MPG that I got from this first trip?.
any idea of cost to make the change to 4.10 and does it affect my waranty?

 

mattebury
I am reading of off the the little white post card that came with my recall notice

ATTENTION NEW EXHAUST SYSTEM TEMPERATURE MONITOR FEATURE
6.4L F-SUPER DUTY
YOUR VEHICULE HAS BEEN EQUIPPED WITH A NEW EXHAUST SYSTEM TEMPERATURE MONITOR THAT WILL FLASH THE CHECK ENGINE INDICATOR LIGHT (SEE PAGE 13 OF YOUR OWNER GUIDE) AND LIMIT THE ENGINE POWER IF AN EXHAUST OVERHEAT CONDITION IS IDENTIFIED.THIS LIMITED ENGINE POWER WILL ALLOW THE FUNCTION OF POWER STEERING AND BRAKING BUT WILL LIMIT VEHICULE ACCELERATION. IF THE CHECK ENGINE LIGHT FLASHES, PULL OVER TO THE SIDE OF THE ROAD AS SOON AS POSSIBLE AND CONTACT YOUR AUTHORISED DEALER.
DEPENDING ON THE SEVERITY OF THE OVER-TEMPERATURE CONDITION,THE VEHICULE MAY OR MAY NOT RESTART AFTER CYCLING THE IGNITION OFF. IF THE VEHICULE RESTARTS, THERE MAY BE LIMITED POWER OR THERE BE FULL FUNCTION. IF THE EXHAUST OVER-TEMPERATURE CONDITION REOCCURS THE CHECK ENGINE LIGHT WILL AGAIN FLASH AND THE VEHICULE WILL AGAIN HAVE LIMITED POWER. AGAIN STOP THE VEHICULE AS SOON AS SAFELY POSSIBLE AND CONTACT YOUR AUTORIZED DEALER TO HAVE THE CONDITION REPAIRED. PLEASE KEEP THIS LETTER IN YOUR GLOVE BOX FOR FUTURE REFERENCE.

I am sur you all got this in your mail with the recall letter that was sent by ford to all of us. I think this BS now you guys now why I am upset because everything is screwd up with this new tecknology, reliabilty, MPG, Power.
oh by the way pull to the side of the road with your 36 feet toyhauler call ford dealer for help on a weekend going to your vacation spot or coming back they will tell you the service dept. is closed call us on monday let me see you have giving us now 62k and you have to deal with this issue on your own.
by the way it is summer 100f to 115f outside temperature the kids are naging so is the CEO (wife) and you will wait for two tow trucks one for your truck and the other for your fiver and you have to pay for the segond towtruck because Ford won't cover the tow on your fiver and I am assuming you had no guests with because the tow truck can only carry two passengers beside the driver of the tow truck this is turning out to be a very nice weekend or vacation.
Reading this card made go what the hell is going on or going to happen to my truck that I bought just for the quality time I am going to spend with my family traveling with it. Do we have to start praying that we get there and back every time we start the engine, and by the way I do but it should not be because I am diving a 2008 ford.

 

Off topic..... Read the repsonses to your previous posts in the Recall Thread.

 

I am going crazy here this is not off topic because this is what is causing these truck to consume more diesel based on what the dealer and every one is stating here.
and by the way do you own a 2008 F-SUPER DUTY or like most of the people here defending or bashing a truck that they do not own because I DO AND THAT GIVES ME THE RIGHT TO COMMENT BECAUSE I AM HAVING TO DEAL WITH THESE ISSUES.
do you work for ford?

 

Overloaded with the throttle wide open will eat your MPG alive. That's why your mileage was so poor.

All things being equal, a 4.10 empty will get worse mileage than a 3.73 empty.

Also, all things being equal, a 4.10 pulling a trailer on the flat will get worse mileage than a 3.73.

Advantage of a 4.10 is on the hills. As you have experienced, pulling 15k up the moutain was not fun and your mileage suffered. Me with the same load, I'd pass you in no time and have better mileage since I don't have my throttle wide open trying to climb the hill.

I would suggest taking your fully loaded truck and trailer (as if you were taking a trip to the desert, include the family) to a public scale and make sure that you are really towing 15k, ask for an axle weigh. You might find that with your toys, fuel and fluids that you are pulling more than 15k. Then, unhook the trailer and re-weigh the truck. This will give you a pin weight and the tru weight of the trailer. I did mine at a CAT scale.

As for replacing the 3.73 gears with 4.10 gears, that'll cost you well over $1,000. You have to change the gears on the front and rear differentials since you have 4WD.