Hello Gentlemen,
I have an 03x, 6.0L with a build date of 05/03 and have 7500 miles on it now. I have been getting 13 to 14 in city and 16 to 17 on highway. I dont have a lead foot [for the most part].
I just havent been real happy with the mpg so I have been playing around some, since I had about 2000 miles on it. I dont know much about deisel motors, but im trying to learn.
First I took off the factory filter system, and put on an, k&n fipk system. Didnt see any differance in mpg , but maybe a slight difference in horse power, couldnt really tell.
Then I went and got a 1704 superchip. O I could tell the difference in horse power. When you step on the gas and it starts smoking rear tires and fish tailing some, I was impressed with that. But it shifted hard and mpg didnt get any better, [after i stopped playing]. I tried all 3 modes within the superchip and not much happened with mpg. So i have taken everything back to stock. I sent the superchip back in to be looked at, and im not sure if i should even put back on the k&n.
My whole thinking was and is that if i can increase horse power and stay out of it, I should get mpg. But that dosnt seem to be happening. According to all I have been reading here within the forums, im doing about average on mpg. I would just like to get better or figure out why I cant.
Please let me know what u think, im opened for ideas and suggestions.
O yeah I read the thread about the, egr, and I dissconected it and no eng, light just a couple of codes.
Also front end drifts to, but I will talk about that later.
Thanks for your time
X 03 Jeff

 

Welcome to FTE!
I have a K&N FIPK. The Dyno run in my Gallery proves that the FIPK gives an estimated 20 HP on top of my Predator Programmer for a total of 387 HP and 723 Ft Lb of torque.
The Blackstone report on my gallery proves that the FIPK on my truck removes twice as much silicone as stock from the air trac of a truck that spends days idling on dusty construction sites.
I picked up 1 to 1.5 MPG. Mine gets 17.5 average driving 80 MPH. About 30% of my driving is around town and racing some unsuspecting Dodge Boy.

Check my gallery and trade that SCMT for a predator!

I plan in the near future to put on a turbo back system. which should pick up 1-2Mpg. 8 ox of Power service added to each 10 galons improves mileage slightly also. I just turned 22,500 miles om mine. You can tell that I love my truck!
By the way, my front end wanders too!

 

2nd welcome Jeff !
03 Ex here too...
and while my concerns about mpg on this 8k lb, Non-aerodynamic beast stopped about the time I bought it, I do pay attention enough to realize that it gets better fuelage than the Jeep 5.9 limited i had before and my wife's current lincoln LS v8 !

And that's with having a turbo back and the Predator (which I use WAY too much to measure any mpg increase!)

AND with having a remote starter for the North Texus heat.... I remote start that thing EVERY time I'm going to get in it - it idles a LOT... but I'm still tickled pink with the mpg I get...

I believe the Predator's making the engine so much more peppy helps me to give it a lot less fuel to get to the speed I want to get to...
Maybe since the throttle is a fly by wire potentiometer they just increased the "virtual" travel so it fools me, but typcially I give it a LOT less throttle to get up to speed (when I'm not mashing it to the floor to get the Predator grin !)

 

I know I will get some remarks about this on my MPG. I bought my 2003 6.0 with 6 thousands miles on it. I had a 3 hour drive to get it home from the dealer. I was amazed yet puzzled the first time I checked, it was completely stock and I got 19 mpg. For the most part I do not drive in town so 17 MPG has been a low for me. My old 7.3 ran 15 MPG religiously. Since I lifted my truck and run 35 inch tires I do not check my MPG anymore for one it is a big truck.

I use the cruise control (lead foot eliminator) when I go long distance, so depending on how you drive it does not sound out of reason. Just my 2 nickles worth of opinion.

 

Oh! I missed the part about front end drift. Could be a tire if it is searching the road as I call it.
Example: pulled belt, radial or lateral balance.
A tire rotation may uncover that problem if it is not visual.
Front toe is a factor, a good alignment shop around the corner is vaulable.

If you can remember a hole you hit in the road or any shock to the front end, that is when it probably happened. A visual inspection with a few wrenches and a tape measure if none of the other apply. Tire pressure causes problems and is an easy check.

 

More than a few have complained about the wandering - I've not noticed as much as some i think because I replaced the stock shocks early on with Rancho 9000's and have a rear sway bar....

A regular user on here, LandYot, has a set of "radius rods" for the rear end and his contention is that the rear end "drives" the front end on these things because of dips on only one side of the road making the spring wrap push one rear tire into a different arc than the other...

I probably didn't do justice to his explanation....
but do a search and get a fresh cup o joe and read away !

 

Thanks All,
For your input, But I still dont get it. I have done these things to my x03 and still no better mpg,. I do use the cruise when ever i can, but still nothing. The mpg is very consistant no matter what I seem to do.
It makes me wander about the injectors, as to why I dont see a change. ???

 

Thanks All,
For your input, But I still dont get it. I have done these things to my x03 and still no better mpg,. I do use the cruise when ever i can, but still nothing. The mpg is very consistant no matter what I seem to do.
It makes me wander about the injectors, as to why I dont see a change. ???

 

Jeff - you said something just now....
Are you using the overhead for your mpg measurements ?
and are you resetting it periodically by pushing and holding both buttons at once ?

Just a thought and trying to understand

And given the amount of foam the diesel does when filling are you filling it to the brim each time consistently ?

You might do a search for the tank mod Choctaw Bob did to cut off the overflow pipe in the tank....

 

As stated on other threads, many of us have noticed the 6.0 gets the best mileage going straight down the road if you keep the rpm slightly under 2000 - mine is that way. If you have any fun at all with mine the mileage goes to crap real fast but mine never has gotten what others report.

 

jdadamsjr - Yeah iI do use the overhead as you mention, but only as a reference I dont trust it a hole lot, even though it seems to be very close to accurate.
When I fill up I wait for it to shut off , then wait a moment, then start the pump again intill it shuts off, then im done. I try to be the same each time, but who knows.
I have been thinking though, about the fuel injectors.
I think they come preset from factory, so if the settings are somewhat differrent from motor to motor, would this explain the difference in mpg from motor to motor ?
And if mine was set at such a point that it dumps a larger amount of fuel, I think that could explain something !
Does this make any sense to you ?
Im just trying to understand also.
Thanks, Jeff

 

Yes... c ur point about diff in fuel charge...
but more fuel being dumped would just make more power at a lesser throttle position, correct ?
just as if you had given it more gas, er ah, fuel, I mean ....
it wouldn't necessarily be more ineffecient though - right ?

and the reaason I asked is that many of us refer to the ovehead as the "lie-o-meter". I've heard VERY few that said it was accurate !

I'm not one to worry AT ALL about mpg in my 8K lb Ex.... ESPECIALLY the way I drive
but some have said that the difference in fill amount - UNLESS YOU SEE THE FUEL at the filler neck each time - could be as much as 5 gallons because of the variables of fuel foaming at different temps coming out of the ground, etc...

like I said, some, even Choctaw Bob, have done the fuel tank mod to cut the overflow? tube and this allows for easier and faster filling because the tube sticks down so far into the tank that it starts to cut off the flow and creates MUCH more foaming...

 

I understand your way of looking at it, and if you are correct that makes sense, but I am not positive on the fuel delivery system or the way the motor functions with more or less fuel.

I have been looking at it from another way, like a 2 cycle type engine. The richer you make it, the more fuel consumpstion you have , with a cooler motor and not as much power. The leaner you make it, less fuel, more power, but a hotter running motor. See im not sure which way is the correct way. When looking at a deisel ??
I have also read some of the threads about the [lie o meter] and feel fortunate that mine seems to be close to correct. As for the foaming I will have to take a look at Choctaw Bobs mod and consider that as well.

 

Yes, there are SO many variables to this mpg thing...
but one thing I'm pretty sure of - diesels fire by compression not by spark...
the combustion process is limited by the fuel and air you dump in...
with the same amount of air... more fuel = more power (up to a limit) then the unburnt fuel goes out the exhaust as black smoke...
(at least that's what mine does with the programmer dumping more fuel in there !)

One thing that helped my mpg was the turbo back exhaust... better scavenging equaled better power meaning better effeciency (if I stayed out of it)

Another thing I found that helped my fuelage was new shocks
Really... stop laughing !

with these new rancho 9000 adjustables I could soften them up enough where I could put more air in my tire and get the same "cushy" ride ... which meant less rolling resistance which helped the fuealge...

c - didn't think I could get here from there, did u ?
c-u
jd

 

I think you got here from there with the results of electro shock therapy. Oh Oh I am getting as PC as Bob.