Edit: For a compiled list of what all the members have contributed, click here.

Original Post:
MPG is something we all strive to get the most out of these days. I've been getting 12-14mpg regularly. That is low, even for my set up, which is a 4x4 7.3 with a 3 inch lift.
What are some places to look for an MPG sucking culprit? Not just for me but for reference for others in the future.

Please refrain from mentioning "No lift" "Smaller Tires" "You drive a big truck deal".
This thread is intended to help diagnose a potential problem with a truck, not a work around like "get a prius"
I have already cleaned the EBP tube and sensor, and that helped a little. Any other suggestions?

 

Like your other thread leaks, Leaking up pipes are big. And as you know ur right foot is huge keeping boost low and rpm's below 2000.

 

I'll check my up pipes. RPMs are almost always under 2000.

 

Tire pressure and boost leaks both rob you of significant fuel Econ.

 

Tires are good and I KNOW I have boost leaks. I push 4lbs at freeway speeds.

 

Trey, as I am new to the PSD world too, I'm curious to see what answers you may get out of this thread.

What tune are you running that you are pulling the low MPGs? Are you sticking to one in particular or is your stated MPG an average?

I'm still on my first tank of diesel at the moment. Haven't had much cause to drive my truck as of yet with vacation and a pregnant wife who can't climb up in to the monster. But, I'm running a stock Superchips tune at the moment until I get a warm fuzzy on what the MPG is. Then I plan to switch over to the economy tune I downloaded yesterday and see how that pans out.

I'd recommend running through the entire driveline to make sure all the mechnicals are 100%. One bad u-joint or wheel bearing can cause a ripple effect that will degrade performance, IMO. Will it degrade it enough to drop you to 13MPG? Doubtful. But I imagine you want every percentage point back that you can possibly get.

 

4lbs at 65 mph is bought right unless you are towing heavy or running up a steep grade! Don't mistake high boost for required boost!

 

I agree. I have fixed all of my boost leaks and put on bellowed uppies. I have a wicked wheel and run 2-4 lbs of boost at 65 mph. I am at about 1800. (these are not towing, but just driving).

The WW is going to produce less boost, but it spins up faster. I was surging and this was the easiest remedy for me.

I am trying to get about 12 MPG while towing. I think that my 4x4 is cost me a couple of MPG.

 

A few things to look at and test.
1. Tire tread pattern. Aggressive tires will normally yield worse mileage.
2. Air intake. I had 5 customers tell me that they all lost 4 mpg after installing the intake. Try putting the stock air box back in.
3. HPOP pressures. Low pressures will prevent optimum atomization.
4. Fuel quality. Make sure you run a good additive.
5. Oil. Good clean oil will help. Remember to always change the HPOP reservoir oil each time.

Jody

 

X2 Jody, too many people jump blindly into installing the first "cold air" intake they see with out actually looking at how that intake pulls it's air and end up with a net loss in pre turbo density by pulling super heated engine compartment air instead of nice cool inner fender or pre core support air, total waste of money! Even the "good" intakes need to be sealed off properly to achieve any gains, IMHO!

 

I almost forgot the biggest mpg killer of all time...LIFT KITS... Every time I have lost at least 4 mpg with a 6" lift kit, @Bobby if you keep the hubs unlocked a 4x4 should keep pretty close within 1or2 mpg!

 

I'm going to assume that you are doing all the things that the driver can do to maximize fuel mileage. The best drivers can get a 30% increase in fuel mileage over the worse drivers in the same vehicle (this has been proven by fleets numerous times). Given that Trey, you might want to read this white paper by Cummins (it is aimed at Class 8 trucks, but the physics applies to other vehicles.

 

You say don't talk about lifts or big tires, but that's the killer, like said, tread design on tires, rolling resistance, tuner's turned way up etc. Changing to Synthetic's in everything that take oil will help, lock out hubs, and not the stock ford's which turn even on auto. Dipetane fuel additive, RBP fuel additive, that's all i use, one gallon of RBP make's 5,000 gallons, and like said driving habit's, and type of terrian you drive in. So many variables, My truck 1tonsrwcc level kit 3.73, 285 michelin's 19 to 20 all the time under 2000rpms, at 75mph 17.5. JMOP.

 

So, using these theories, if I ditch the 6637, 4" lift and 285 mud tread tires I should get back close to 10mpg??????

Take all mileage claims with a grain of salt. Not saying that anyone here is lying, but there really are too many variables to apply to mileage being the same for everyone.

 

The reason I didnt want to talk about lift kits and tires is becasue even with those, I shouldnt be getting 12mpg. That means there is a problem somewhere.