Why such dismal fuel mileage??

[10 FOOT INVADER]

Re: Why such dismal fuel mileage??

My 90 town car gets about 12-14 mpg on the hwy pulling 4000-4500lbs. Avg speed about 70mph, a little less going up steep hills. Only time I come out of overdrive is a steep hill and need the lower gear. Do not know what it gets without the boat. It and the trailor are one. The trick to more mpg=steady driving habbits.

 

[reelfishin]

Re: Why such dismal fuel mileage??

My 90 town car gets about 12-14 mpg on the hwy pulling 4000-4500lbs. Avg speed about 70mph, a little less going up steep hills. Only time I come out of overdrive is a steep hill and need the lower gear. Do not know what it gets without the boat. It and the trailor are one. The trick to more mpg=steady driving habbits.

Your doing good, I had both a 1989 Town Car and Crown Vic, the TC got only 15 on average and it never pulled a trailer, my CV got no better than about 12 mpg on a good day with no trailer, and that could go as low as 5 or 6 with a trailer. The CV had a full tow package and a 3.55 posi rear and I had rebuilt the trans in later years to make it more tow friendly which actually improved the mileage. The 5.0 HO motor helped pulling power a lot too. (It was converted to the HO motor after the original motor failed when the car was near new).
I actually improved my mileage when I bought my 1991 1 ton Dodge van which gets 10 towing and about 15 empty.

 

[Feorine]

Re: Why such dismal fuel mileage??

I have a 2001 Excursion, 7.3L diesel, and 3.73 gears. My tires are LT265R75-16, the stock size. I turn about 2000 rpm at 70 mph, in overdrive.

According to the owners manual, and several truck forums I read regularly, these are meant to tow in overdrive, as long as the transmission isn't hunting between 3rd and 4th, or going in and out of torque converter lockup.

Driving 65-70 mph at 1800-2000 rpm, with 4.10 gears, doesn't sound right to me.

According to my mileage computer (resetting it, then driving a half hour or so with cruise control on) I get a huge mileage difference when running 1800 rpm versus 2100 (about 65 versus a little over 70)

I've never towed anything that heavy at that speed and distance, but I regularly get 19 mpg to 21 mpg running empty on the highway, depending on speed.

Ron

 

[muskie hunter]

Re: Why such dismal fuel mileage??

I have a 2001 Excursion, 7.3L diesel, and 3.73 gears. My tires are LT265R75-16, the stock size. I turn about 2000 rpm at 70 mph, in overdrive.

According to the owners manual, and several truck forums I read regularly, these are meant to tow in overdrive, as long as the transmission isn't hunting between 3rd and 4th, or going in and out of torque converter lockup.

Driving 65-70 mph at 1800-2000 rpm, with 4.10 gears, doesn't sound right to me.

According to my mileage computer (resetting it, then driving a half hour or so with cruise control on) I get a huge mileage difference when running 1800 rpm versus 2100 (about 65 versus a little over 70)

I've never towed anything that heavy at that speed and distance, but I regularly get 19 mpg to 21 mpg running empty on the highway, depending on speed.

Ron

You are correct. I pulled the boat in overdrive. The transmission did not hunt and the truck didnt struggle at all. The engine ran 1800-2000 rpm at 70 mph. I could slightly hear the whistle of the turbo the whole trip.
Here is the main point of the post. My 1997 yukon rated to pull 6500 lbs achived 8 mpg from columbus ohio to st josephs michigan. The Yukon has a smallblock 350 fuel injected motor ran in drive not overdrive(ran almost 3000 rpm). The Ford f-350 7.4 liter turbo diesel is rated to pull I believe 17000 lbs was run in overdrive from columbus ohio to st joseph michigan and go 8 miles to the gallon. both trucks were driven easily in order to obtain the best mpg. I cant understand or believe that the ford (which wasn't working hard at all) didnt far surpass the Yukon (which was getting its guts worked out) in fuel mileage.

 

[ne7800]

Re: Why such dismal fuel mileage??

What were the actual numbers? miles drivin, gallons used

 

[muskie hunter]

Re: Why such dismal fuel mileage??

What were the actual numbers? miles drivin, gallons used

I will get the receipts and records out of the car and post them tomorrow. Trust me, the fuel mileage is correct for both vehicles.

Thanks Steves

 

[captharv]

Re: Why such dismal fuel mileage??

My Buddy has a 28' boat on an aluminum trailer. He weighed it at a scale, and the towing weight is 10,400. He is pulling with a GMC 2500, 6.0 with tow package. He is getting between 6 and 7 MPG depending in the trip.
I wouldn't complain too loud about getting 8 with the Yukon.
Try towing at 50-55, and you mileage will improve.

Note: Ford sets up their tow modes for a reason. Use the vehicle with those parameters, and the fuel will improve drastically. Tow modes are there to let the engine/tranny operate more efficiently with heavy loads. Try towing with the tow mode on, at 55-60.

 

[muskie hunter]

Re: Why such dismal fuel mileage??

Ok here are the numbers. We drove 919.0 mile and burned 111.0 gallons of diesel fuel for an average over 4 tanks of 8.2 mpg. This was with a 7 liter Ford f-350 turbo diesel run in overdrive at 65-70mph on flat ground.

My 1997 GMC Yukon 2door 5.7 liter vortec achieved the exact same mileage on the same trip ealier in the year with the same load.

 

[Silvertip]

Re: Why such dismal fuel mileage??

If you counted the initial (pre-trip) fill-up in the total you created a huge error. You start adding with the first fill-up AFTER the initial fill. You haven't used the fuel you put in initially until the first fill-up after starting the trip.

 

[Silvertip]

Re: Why such dismal fuel mileage??

If you counted the initial (pre-trip) fill-up in the total you created a huge error. You start adding with the first fill-up AFTER the initial fill. You haven't used the fuel you put in initially until the first fill-up after starting the trip. For example, if you topped off the tank with 25 gallons at the beginning of the trip and added that amount into the 111 gallons you actually used only 86 gallons for the trip. That equates to a little under 11 MPG.

 

[Silvertip]

Re: Why such dismal fuel mileage??

I hate getting interrupted in the middle of a post. Sorry for the duplicate post. Meant to edit the first one.

 

[Gary H NC]

Re: Why such dismal fuel mileage??

It all boils down to, it is what it is.....

My Tahoe is the same truck as his Yukon.Same engine and all.
I get 8 to 9 towing but i tow with a heavy foot on the gas.I run 65-70 on the interstate.
Overdive off and about 3000 rpm on the tach at 65 mph.

I did do some upgrades on the truck to help it breath better.
High flow dual exhaust,K&N cold air intake and a towing performance program on the engine.
It greatly improved power towing in the mountains and maintaining highway speeds.
Towing the boat about 4000 pounds loaded i can keep my foot out of it and get 11 to the gallon no problem.

As far as the Ford truck in question some of the older model Fords just like the fuel.

Hey,gas prices are down...enjoy it and stop being worried..

 

[driz]

Re: Why such dismal fuel mileage??

I suspect thats all you are gonna get hauling all that weight and bulk. No free lunch here at all. About all you can do is slow down and see what that does. I found an amazying difference in mileage by dropping down to the speed limit or below. I hated it at first but its easy enough with practice you can learn to live with it. I don't think I would want to get a flat or have to try to stop quick at over 70 with all that weight either. When I haul something big I rarely go over 65 especially down hill. Don't feel too bad on the numbers. I just did a long trip a week ago with a 5000 lb horse trailer and came in at a steady 10 mpg with a 1990 Silverado 350 /4spd auto.

 

[muskie hunter]

Re: Why such dismal fuel mileage??

It all boils down to, it is what it is.....

My Tahoe is the same truck as his Yukon.Same engine and all.
I get 8 to 9 towing but i tow with a heavy foot on the gas.I run 65-70 on the interstate.
Overdive off and about 3000 rpm on the tach at 65 mph.

I did do some upgrades on the truck to help it breath better.
High flow dual exhaust,K&N cold air intake and a towing performance program on the engine.
It greatly improved power towing in the mountains and maintaining highway speeds.
Towing the boat about 4000 pounds loaded i can keep my foot out of it and get 11 to the gallon no problem.

As far as the Ford truck in question some of the older model Fords just like the fuel.

Hey,gas prices are down...enjoy it and stop being worried..

Oh Im proud as punch of the yukon. I feel 8 mpg is great for towing something so large.

 

[Scorpion 210 LTD]

Re: Why such dismal fuel mileage??

I have a 99 F250 7.3 diesel truck with a 6 speed. I get 18 MPG empty average. I tow a 10K trailer with it and last trip pulled from MA to NC and back. Average 12.8 MPG over the 2K miles. If that Ford is getting much worse MPG, there is something wrong with it.

 

[muskie hunter]

Re: Why such dismal fuel mileage??

I have a 99 F250 7.3 diesel truck with a 6 speed. I get 18 MPG empty average. I tow a 10K trailer with it and last trip pulled from MA to NC and back. Average 12.8 MPG over the 2K miles. If that Ford is getting much worse MPG, there is something wrong with it.

It sounds like the general concensis. We drove 910 mile on flat ground in overdrive and got 8.2 mpg. We maintained our speed between 65-70 and never pushed the truck.

 

[RedsFearMe]

Re: Why such dismal fuel mileage??

I have a 2000 Ford F250 7.3D, 3.73 gears. I tow three trailers, 12900# 35' Fifth Wheel, 7000# 23' Draw Travel trailer, and a 5900# Offshore CC boat. I get 11, 14, 15 mpg respectively. I keep about 19mpg hiway unloaded at around 70-75mph. If your dropping that 7.3L to 8mpg, your doing something wrong or your speeds are off. In my other truck, even the 4.10 gears in the 7.3 F350 Dually get 18mpg unloaded and approx. 10mpg towing nearly 14000#.
My father has a 99 Dodge 2500 Cummins that is getting almost 14mpg towing 13K#. Granted he doesnt know what 65mph feels like, he doesnt go over 60 towing.

We both sit at approx. 1900 RPMs at that speed.

 

[Gary H NC]

Re: Why such dismal fuel mileage??

That Ford diesel may have some problems,dirty fuel filters,injectors or fuel system problems.
I know the Dodge Cummins motors need a 50,000 mile overhead service on the valves ect..
Maybe the Ford is overdue some major service schedules.

 

[RedsFearMe]

Re: Why such dismal fuel mileage??

Another note about the possible inaccuracies of some of our tow records. I do alot of towing and keep immaculate records. I also use a 100 Gallon jump tank and usually end up pumping approximately 128 gal each time. I keep the records down to the time of day and the ambient temp at fill up. Noting that extreme heat drops mileage compared to cold temps.

 

[reelfishin]

Re: Why such dismal fuel mileage??

Another note about the possible inaccuracies of some of our tow records. I do alot of towing and keep immaculate records. I also use a 100 Gallon jump tank and usually end up pumping approximately 128 gal each time. I keep the records down to the time of day and the ambient temp at fill up. Noting that extreme heat drops mileage compared to cold temps.

What temps do you consider extreme heat?
It's been my experience here that cold temps, below freezing, use more fuel, on both diesel and gas. It takes longer for the motor to come up to efficient temps when its cold and a gas motor will run richer when cold due to harder start up conditions. Wheel spin, tire slip and slower driving along frozen road no able to get into your upper or overdrive gears, all while running the defrost and wipers full bore to keep the glass clear usually makes for lower mileage. Not to mention the amount of time the truck is often let run just to warm up the cab to make it fit to drive. You get no mileage sitting still at idle.
The only mileage loss I see during hot weather here might be the added fuel used to run the AC or time not wanting to get out of the air conditioned cab on a hot day.