[plvaulter06]

I just bought a 2009 quad cab longbed 4x4 3.73 68re 6.7L with 165k miles (100% stock when i bought it). The next day, I added a 4" MBRP turbo back exhaust (w/ muffler), AFE stage II inatake, H&S EGR delete kit, smarty jr set to performance, and switched the oil to 5w40 full synthetic.

The truck is stock height and has stock size highway tires inflated to 80psi.

I just filled up the truck with diesel, added some power service and drove down 470miles of flat interstate with cruise set at 69-70mph. It drank 30.1 Gallons for a hand calc 15.61MPG.

any ideas where to start on improving from here? Please tell me you guys can get better than this.

 

[Cwilliams]

I have full exhaust, h&s tuner and fully deleted and get 14.5-15.5 mpg. And I am lifted 6 inches and 37" tires. You should be seein better mpg as is if I was guessing.


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[tuff4x4]

14.5-15.5 is pretty bad for being deleted, i get that and am completely stock..
i guess i just want to know what mpg do you THINK you SHOULD get?

 

[rgnagy74]

My 6.7 was getting about the same as yours and after I did the deletes and had Sartlight Diesel tune it with EFI LIVE I am very happy with it! Runs smoother, cooler and best of all I'm now getting 19.5 hand figured on the hwy. Check into EFI LIVE!

 

[pwr2tow]

I just bought a 2009 quad cab longbed 4x4 3.73 68re 6.7L with 165k miles (100% stock when i bought it). The next day, I added a 4" MBRP turbo back exhaust (w/ muffler), AFE stage II inatake, H&S EGR delete kit, smarty jr set to performance, and switched the oil to 5w40 full synthetic.

The truck is stock height and has stock size highway tires inflated to 80psi.

I just filled up the truck with diesel, added some power service and drove down 470miles of flat interstate with cruise set at 69-70mph. It drank 30.1 Gallons for a hand calc 15.61MPG.

any ideas where to start on improving from here? Please tell me you guys can get better than this.

Clean your MAP sensor on the back of the air horn, held on with a torx bolt. Use nonchlorinated brake cleaner. If it's really caked you can use a tooth pick but be very careful.

 

[Cwilliams]

Tuff4x4 if your comment was too me about getting 14.5-15.5mpg, it is only bad because I have a 6" lift and 37" tires. The OP said he got 15.61 and he was completely stock. The OP should be getting better than 15mpg if I can do it with my lift and big tires.


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[09_6Speed_ C&C]

on my recent long trip, may have gotten better but there was alittle bit of traffic here and there, i averaged 19.1..(hand calculated)
Truck is 09 3500 4-door Cab and Chassis 6-speed with 9.4ft skirted cm flatbed (all stock except southbend 150,000 miles) just ordered 5'' flo-pro straight pipe and minimax is coming in a couple of months so mileage should get better

 

[Michigandodgeguy]

you probably had to run a tank through to work some of that caked on soot out of your turbo and other things haha.. i would guess youre going to keep getting 19 or so now..

but yeah, i second looking into efi live, as well as cleaning your map sensor

 

[4NEATR]

X2 on cleaning the MAP sensor
with that truck and mods, you should see close to 20mpg on a long drive

 

[dapayne]

Soaree Brad fo me spelen an gramher erhors', thats funny!!! Driving style has alot to do with it also, the longer it takes to get up to speed = less fuel. Try driving it and keep the egt under 800, harder than ya think, I just don't have the patience's.

 

[tuff4x4]

sorry didn't see that in you sig

 

[GoinDownhole]

There's also winter blend fuels and B20 blends out now with the season... that can kill some of your mileage. I've seen over 3mpg lost from these fuels from friends accounts.

 

[MegaCab41]

I've dropped 2 mpg with winter fuel!!

 

[plvaulter06]

Since my original post last week...

I cleaned the map sensor. It was completely sooted over. I also replaced the fuel filter, and put a new set of 235/80r17 Michelin LTX M/S 2's on the truck.

1 tank of around town for 14.6mpg

1000 miles of straight interstate at 70-75mph... 15.76 and 15.42MPG

This is BAD. I have yet to get better than 15.xx MPG

Is there any chance that I would get better with the smarty turned down to 1 aka stock? I have seen many reports of people with 100% stock trucks, no deletes and no tuners that get better than 15mpg on the highway.

 

[pwr2tow]

Romping on it set to SW3 will eat fuel.

Have you went into the adjust options menu.
Change the Timing to 4, it's most advanced timing and will give better MPG.
Set torque to 2 or
even less aggressive take offs setting 1

Personally I would leave the Torque setting alone for now. At least until you figure out what's up with your truck.

Is that AFE air cleaner a oiled filter? Chances are the MAF and IAT sensors are contaminated with oil. Use dry filters only on these diesels.

I think on the AFE there's suppose to be a donut type thing you put on the MAF sensor. Did you put one on. without it the air flow is messed up and that would give false readings to the ECM which might be dumping in more fuel then needed. I could be wrong on the AFE though.

Hopefully someone who runs an AFE can chime in.

 

[plvaulter06]

The filter is a dry filter. If those sensors are contaminated, it isn't from the filter that is on it.

Slow acceleration onto the freeway, 1000 of cruise control with two stops for fuel. There was no racing, no speeding, all business.

That is why I am so blown away that it will only get 15mpg

The torque management is on 1

One of the interstate tanks was on timing 4. The next tank was on timing 2. They were within .3mpg of each other.

 

[plvaulter06]

On 2nd thought... The truck had a stock replacement k&n in it when I bought it...

Can those sensors be cleaned? Or should they be replaced?

 

[pwr2tow]

On 2nd thought... The truck had a stock replacement k&n in it when I bought it...

Can those sensors be cleaned? Or should they be replaced?

I think you found your culprit.
Not sure if those can be cleaned I think they can (too many beers already) with MAP/MAF sensor cleaner or non-chlorinated brake cleaner.

Make sure it's non-chlorinated brake cleaner if you use brake cleaner. If those sensors can be cleaned the non-chlorinated brake cleaner is just as good, just throwing that out there in case you have some laying around.

 

[plvaulter06]

Well I cleaned the map sensor again and the two on the intake with MAF cleaner.

It definitely did something. The vanes in the turbo are much more conservative now.

First tank after clean sensors was 16.9mpg. Definitely room to improve still but not the worst ever for running 70-80mph in below zero weather.

Thanks guys. If anyone has any more ideas feel free to let me know.

 

[Michigandodgeguy]

winter fuel will kill you.. i usually always keep diesel kleen in the tank to counter-act it.. i mean, its like $18 for a gallon and lasts me all winter basically..

might as well switch to EFI Live haha.. i know that may not be in the cards but its something to consider.. First tank on my economy tune i got 17 mpg, i was used to seeing around 15 with the smarty sr.. and this is still winter fuel so i could see better when summer comes.. havent drove on the highway at all with it yet either, and my tires and level dont help