Hi

I've been lurking here reading mostly for the last couple of months looking for the answer to my low MPGs while towing. It started out I had low MPGs empty or towing but after following some of the suggestions here my empty MPGs are back to 19 - 20 mpg where they were when I first bought the truck.

First off its a 2000 F250, SuperDuty 2 wheel drive with the manual transmission. When i first started I was getting 14.5 mpg "Bone Stock" running 75 - 80 mph Sacramento CA, to Beaumont TX. I then put on my 8000 lb trailer for the return trip and got 12.3 mpg.

After cleaning out the EBPS and running several tanks with Diesel Kleen, running empty Beaumont TX, to New Orleans I got 20.2 mpg, 70 mph, Cruise Control. I added the Banks 4" exhaust and still got 19+ mpg around town.

But when I hooked up the trailer my milage went right back down to 12.3 mpg same as before the milage improvements.I keep checking these boards looking for clues and every thing I find says I'm right in line with what I should be getting, ie: 4 lbs boost at 70 mpg, EGTs 600 F @ 70 mph.

I've since added the Banks 6 Gun and Big Head Waste Gate actuator but am not expecting that to fix my problem

any suggestions of where to look

 

You are simply NOT going to do any better towing that kind of load.

 

Although I think your mpg's are fine, what type of trailer is it?

 

Thats what I get towing.

You are seeing better mpg's empty that I am though.

 

When the truck was new I used to tow my 21 ft Daycruiser with no significant loss of MPGs. Granted the Daycruise was 5000 lbs and extremely aerodynamic when compared to a 5th wheel trailer - but it still leaves unanswered questions for me.

Prior to cleaning out the EBPS tube and running several tanks with Diesel Kleen additive the MPGs were 14.5 empty and 12.3 hauling the 5th wheel.

The Empty weight MPGs came up to the original mileage but the hauling MPGs remained the same

Additionally from the 6 Gun display I haven't seen Boost in excess of 17 psi yet. Not that I've really laid into the throttle yet - just that I haven't seen it. Arn't these turbos capable of a little bit more boost

 

Your mileage seems to be right in line with what I get, empty & a little better than I get towing. Makes a huge difference when your pulling a 12' high wall behind u (5er) vs. a little boat that is level or below the truck level. Towing weight is'nt so much a factor with these trucks as height of what your towing, from my experience. Head wind will factor into the equation also, sometimes as much as 1 -2 mpg with really strong wind conditions. Hilly terrain is also a big factor as I'm sure u know.

 

I don't know what tunes you have on your 6 gun.
Is it what we call CANNED TUNER ? where the tunes can't be changed. ?
I don't know much about the 6 gun.

You need to have a tune just for towing.
like 60 or 80 hp with the shift pattern and other change's to lower the egt's and boost

You may only get 1 or 2 miles more, but custom tunes makes it WAY easier on you motor and drive train

 

What speed and RPM do you tow at?

I noticed a huge difference in mpg towing a U Hual auto transporter and 2,100lb car when I kept my RPMs under 2,000.

 

70 MPH with 4 tons chasing you? I'd tone it down a bit, like AMG-SM said - get 'er under 2 grand or just pay for the quicker arrival time.

Your boost is in line with a stock configuration (17 PSI), you'd have to drop a little coin to get it up there. Air... lots of air.

• Air in (like the AIS or 6637).
• Air out (4" turbo-back exhaust).
• Red-line disconnect and plug.

A good tow tune will serve you better than a power tune. Since you're getting 19-20 MPG empty (Hand calculated, right? Liedometer doesn't count.), it doesn't sound like boost/exhaust leaks. 4 PSI is about right when empty at 65-70, but it should fluctuate between 12 and 0 on hills and in the wind. During a hard acceleration, you should pop 17, but no way to get past 22 on stock tune or 25 with power tunes and red line connected to the wastegate.

What's your elevation and are you blowing coal?

 

Its already been said. I get about the same towing.

Steve

 

It always blows clean - no black smoke. I bought this truck new and have changed the oil religiously every 3 - 5000 miles

Again the truck is 2 wheel drive / Manual gear box, hence the mileage. I know the same year truck with automatic and 4 Wheel Drive runs 16-17 mpg at best. This truck when running properly always did run 19-20 mpg @ 70 mph

70 mph with the 4:10 rear end translates to 2050ish RPM

My MPGs are hand calculated at the gas pump with the odometer. Lying to myself wouldn't make the cost of a tank of gas feel any better. The last run home with the trailer was Beaumont Tx. to Sacramento Ca. so the elevations varied a bit

Call it paranoia if you must but at 1 point running through the Texas Hill Country (some where around Ft Stockton) all of a sudden I get 15 MPG towing the trailer through the hills - then it goes right back down to 12.3 mpg by the time I hit El Paso

Like some thing turning on and off a switch or unsticking and then sticking up again. Like I said I was asking for advice

Truck used to sit quite abit while I commuted back and forth to the Bay Area for work in a little 4 cylinder commuter buggy. Hence the reason it was so gummed up that the diesel additive had a profound effect. But with the economy being what is has been for the last 2 years I've been chasing work around the country with a 5th wheel trailer trying to stay busy

 

One of the members just discovered his wastegate would stick open, that would depower the truck. I had a bad MAP signal - that let me burn real clean, but the power and economy sucked. There are things to check in that last link in my signature... click on that.

 

Thanks Tugly

That is a good direction to start. I work with Instrumentation so I'm sure I have a calibration standard for pressure around here that I can use to check the MAP sensor.

I would have thought the addition of the 4" exhaust would have given me a little some thing extra while towing