Gas mileage report [4.9L / manual OD]

[ctubutis]

My truck came with the tiny air dam which was supplied with some models.

For comparison's sake, I'll now list my stats:

DOWNHILL (Denver -> Skiatook)

=====================

3 gasoline stops:

@Colby, KS: 235 miles traveled, 24.775 gallons, 9.48 MPG

@Wichita, KS: 273 miles traveled, 32.414 gallons, 8.42 MPG

@Skiatook, OK: 156 miles traveled, 18.32 gallons, 8.5 MPG

---------------------------------------

664 miles total

=========

Usual speed was close to 65 MPH except directly out of Wichita where I ran closer to 75 MPH.

UPHILL (Skiatook -> Denver)

===================

3 gasoline stops:

@Hays, KS: 333 miles traveled, 30.25 gallons, 10.3 MPG

@Colby, KS: 100 miles traveled, 10.983 gallons, 9.1 MPG

@Denver, CO: 236 miles traveled, 25.514 gallons, 9.24 MPG

-------------------------------------

669 miles total

=========

Usual speed was close to 55 MPH except, again, near the end of the trip and I was in a hurry.

~~

142.256 gallons total, $383, average price $2.69/gal. The lesson learned is, driving 65+ MPH costs ~2 MPG over 55 MPH.

~~

The thing gets ~5 MPG city.

~~

I experienced a fuel delivery issue beginning someplace in mid-Kansas, the engine was starved for gas over 60 MPH and I felt lucky to be able to hit 65 MPH occasionally. I am pretty sure the problem was caused by a clogged fuel filter but am not sure yet; the pump puts out close to 8 psi but I haven't yet tested for volume. The fuel filter was brand new (installed less than a week before I left home but after replacing the front tank sending unit a few weeks prior), one of those glass things that Fuzzy doesn't like. Supposedly they can be disassembled & cleaned or the innards replaced, I got it at a local Advance parts store.

I actually first experienced this problem someplace in Skiatook on Saturday, before Gary ever drove the thing much less worked on it; I blew it off, thinking maybe it was vapor lock.

~~

Also, right before I got home, I noticed the oil/gas/water gauges all pegged out to the right; seems like it's time for an ICVR.

~~

I replaced the fuel filter today (got one of those see-thru plastic things, much larger than the glass type) and took it to the gas station; it runs OK but the idle speed is ~500 RPM (according to the factory tach)... Gary, didn't you tell me to close both idle adjustment screws 1/16th of a turn, and then adjust the idle speed screw if needed? I have a vacuum gauge, I'm just looking for maximum vacuum, correct? But there's no dieseling or run-on. :)

I would still like to get rid of the pinging (which has led to me using medium-grade unleaded the past 10 years).

NB Gary, there is virtually zero cellphone signal strength (T-Mobile) in western Kansas & eastern Colorado, so I couldn't answer you at the time.

[Gary Lewis]

For comparison's sake, I'll now list my stats:

DOWNHILL (Denver -> Skiatook)

=====================

3 gasoline stops:

@Colby, KS: 235 miles traveled, 24.775 gallons, 9.48 MPG

@Wichita, KS: 273 miles traveled, 32.414 gallons, 8.42 MPG

@Skiatook, OK: 156 miles traveled, 18.32 gallons, 8.5 MPG

---------------------------------------

664 miles total

=========

Usual speed was close to 65 MPH except directly out of Wichita where I ran closer to 75 MPH.

UPHILL (Skiatook -> Denver)

===================

3 gasoline stops:

@Hays, KS: 333 miles traveled, 30.25 gallons, 10.3 MPG

@Colby, KS: 100 miles traveled, 10.983 gallons, 9.1 MPG

@Denver, CO: 236 miles traveled, 25.514 gallons, 9.24 MPG

-------------------------------------

669 miles total

=========

Usual speed was close to 55 MPH except, again, near the end of the trip and I was in a hurry.

~~

142.256 gallons total, $383, average price $2.69/gal. The lesson learned is, driving 65+ MPH costs ~2 MPG over 55 MPH.

~~

The thing gets ~5 MPG city.

~~

I experienced a fuel delivery issue beginning someplace in mid-Kansas, the engine was starved for gas over 60 MPH and I felt lucky to be able to hit 65 MPH occasionally. I am pretty sure the problem was caused by a clogged fuel filter but am not sure yet; the pump puts out close to 8 psi but I haven't yet tested for volume. The fuel filter was brand new (installed less than a week before I left home but after replacing the front tank sending unit a few weeks prior), one of those glass things that Fuzzy doesn't like. Supposedly they can be disassembled & cleaned or the innards replaced, I got it at a local Advance parts store.

I actually first experienced this problem someplace in Skiatook on Saturday, before Gary ever drove the thing much less worked on it; I blew it off, thinking maybe it was vapor lock.

~~

Also, right before I got home, I noticed the oil/gas/water gauges all pegged out to the right; seems like it's time for an ICVR.

~~

I replaced the fuel filter today (got one of those see-thru plastic things, much larger than the glass type) and took it to the gas station; it runs OK but the idle speed is ~500 RPM (according to the factory tach)... Gary, didn't you tell me to close both idle adjustment screws 1/16th of a turn, and then adjust the idle speed screw if needed? I have a vacuum gauge, I'm just looking for maximum vacuum, correct? But there's no dieseling or run-on. :)

I would still like to get rid of the pinging (which has led to me using medium-grade unleaded the past 10 years).

NB Gary, there is virtually zero cellphone signal strength (T-Mobile) in western Kansas & eastern Colorado, so I couldn't answer you at the time.

Wow! That thing is thirsty! Even Big Blue gets 11 - 12 MPG at 65 MPH. But he's running 3.54 gears and you have 4.11's. On the other hand, Big Blue probably weighs more with the front bumper, winch, auxiliary battery, and the toolbox absolutely full of tools. And then there are the massive tires which weigh 65 lbs each - just for the tire, not including the wheel.

Anyway, to tune the idle mix use the vacuum gauge and dial it in for max vacuum. But turn each screw in 1/4 turn increments and then go to the other one to keep them roughly in sync. You should find that going clockwise/in will bring the idle speed and vacuum up, so keep doing that until the vacuum starts to drop. Back it up 1/8th to 1/4 turn on each and you should be at max vacuum. Then set your RPM with the idle stop screw. But, keep it low enough that there's no dieseling.

Did replacing the fuel filter fix the problem? Perhaps that was the problem I was feeling where full throttle actually was bogging where 3/4 throttle wasn't?

On the pinging, I'd dial the initial timing back to 8 or even 6. I think you have too light of springs in the dizzy and you are getting your mechanical advance too soon. So take some of that out with less initial advance.

Oh yes: ICVR.

[Ford F834]

Thank you David, for your meticulous documentation. The different numbers and different driving speed adds further value.

And thanks Chris for your numbers and observations as well. I take it you do not have an overdrive transmission?

I don’t think there is much arguing that speed hurts mpg, but it is curious how gearing changes the curve. I’m just going to leave a couple observations on the table:

Jan’s truck got 21 mpg at 60-65 which dropped to 19 at 70-75 on the drive to LA. His final drive ratio is 2.73.

On a trip to New Mexico I did an experiment with my [diesel] truck (similar to Jan’s but with a 3.20 final drive ratio). At 65 I got 17mpg. At 75 I got 17mpg. Back country driving at 45 I also got 17 mpg. No matter how I drove or what I did it was hard to deviate from that number (unless I was towing). My theory is that it was under geared and over revving at the point of optimal speed versus wind resistance. With the overdrive off, it was similar, but a flat 15mpg. Note without overdrive i couldn’t attain highway speed to even make a comparison. Eventually I will be able to see what it does at a 2.43 final ratio. 🙂

[Rembrant]

No matter how I drove or what I did it was hard to deviate from that number (unless I was towing).

I drive a diesel VW that is about the same, and I always kind of assumed it was a diesel thing. The MPG doesn't seem to change much, no matter what type of driving or speeds I'm doing. I do tow a trailer with it once in a while, and in that case, it cuts the MPG in half. However, from rural and city driving to highway at 65 or 75 MPH, the mileage seems to stay about the same.

 

[Gary Lewis]

No matter how I drove or what I did it was hard to deviate from that number (unless I was towing).

I drive a diesel VW that is about the same, and I always kind of assumed it was a diesel thing. The MPG doesn't seem to change much, no matter what type of driving or speeds I'm doing. I do tow a trailer with it once in a while, and in that case, it cuts the MPG in half. However, from rural and city driving to highway at 65 or 75 MPH, the mileage seems to stay about the same.

The MPG on my wife's 2014 GLK with a twin-turbo'd diesel varies quite a bit due to conditions - and use of the blowers. Once we drove due north with a breeze from the south on state roads at 55 MPH and got 42 MPG, which was the best ever, although we backed it up with the next tank at that level.

At 70 - 75 MPH it gets between 33 & 35 MPG. But if we run 80+ on the turnpike the MPG drops to closer to 30.

And, the cruise control makes the MPG go down. The 42 MPG was manually feeding it, but if you use the cruise it recovers the speed too quickly and drops the MPG.

[Ford F834]

No matter how I drove or what I did it was hard to deviate from that number (unless I was towing).

I drive a diesel VW that is about the same, and I always kind of assumed it was a diesel thing. The MPG doesn't seem to change much, no matter what type of driving or speeds I'm doing. I do tow a trailer with it once in a while, and in that case, it cuts the MPG in half. However, from rural and city driving to highway at 65 or 75 MPH, the mileage seems to stay about the same.

My Jetta TDI gets about 50mpg almost no matter what I do. If I drive it hard and set the cruise at 80mph going up 6% grades I can get it down to 48mpg. The only time that I got less than that was when I had a massive fuel leak on my injection pump. Then I got 44 and a diesel fuel headache. Aerodynamically, well, I have to jack it up to fit an oil drain pan under it, and my front bumper cover has been ripped off dozens of times because it’s below curb and parking barricade height. I figured that was the main reason speed didn’t change mpg very much.

So maybe it is a diesel thing, but Jan’s truck did loose 10% going from 60-65 to 70-75. I wonder how it would have done at 50-55? Hard to compare now as he has added a turbo, messed with timing, and Europe fuels are different than ours.

[Gary Lewis]

My Jetta TDI gets about 50mpg almost no matter what I do. If I drive it hard and set the cruise at 80mph going up 6% grades I can get it down to 48mpg. The only time that I got less than that was when I had a massive fuel leak on my injection pump. Then I got 44 and a diesel fuel headache. Aerodynamically, well, I have to jack it up to fit an oil drain pan under it, and my front bumper cover has been ripped off dozens of times because it’s below curb and parking barricade height. I figured that was the main reason speed didn’t change mpg very much.

So maybe it is a diesel thing, but Jan’s truck did loose 10% going from 60-65 to 70-75. I wonder how it would have done at 50-55? Hard to compare now as he has added a turbo, messed with timing, and Europe fuels are different than ours.

Just got back from the Billups wedding. While there one of Cash's friends asked me how I know Cash. I asked him if he knows Carlos, and the discussion about Ford trucks was on.

Turns out he has a '95 F250 w/a factory-turbo'd 7.3/E4OD combo. Said it got 13 MPG running 70 MPH towing a Chevy 3/4 ton on the car hauler, and did it easily. And it gets in the high teens just running down the highway light. But, the truck is from Iowa and the salt they use on the road is eating it up.

I suggested to him that he sell the truck to one of us so we can transplant that drive train into a Bullnose. And later that got me to thinking about Big Blue. I'm going to great lengths to EFI him and add the ZF5, and by doing so I'm hoping to get 14 MPG on the highway - light. And his '95 gets essentially that pulling a 3/4 ton truck on a car hauler? What's wrong with this picture?

Is he wrong? Is it possible a factory turbo'd 7.3/E4OD can get that kind of MPG?

[Ford F834]

Just got back from the Billups wedding. While there one of Cash's friends asked me how I know Cash. I asked him if he knows Carlos, and the discussion about Ford trucks was on.

Turns out he has a '95 F250 w/a factory-turbo'd 7.3/E4OD combo. Said it got 13 MPG running 70 MPH towing a Chevy 3/4 ton on the car hauler, and did it easily. And it gets in the high teens just running down the highway light. But, the truck is from Iowa and the salt they use on the road is eating it up.

I suggested to him that he sell the truck to one of us so we can transplant that drive train into a Bullnose. And later that got me to thinking about Big Blue. I'm going to great lengths to EFI him and add the ZF5, and by doing so I'm hoping to get 14 MPG on the highway - light. And his '95 gets essentially that pulling a 3/4 ton truck on a car hauler? What's wrong with this picture?

Is he wrong? Is it possible a factory turbo'd 7.3/E4OD can get that kind of MPG?

Gary, a ‘95 would be a direct injection Powerstroke 7.3, computer controlled and a major headache to transplant. It is certainly do-able, but not for the faint of heart. I’m not wanting to kick the IDI vs. PSD wasp nest, but a 6.9 or 7.3 IDI would be a lot simpler swap and would return similar results as far as mpg. Justin Anderson pulls a large travel trailer from Maple Valley WA to Yuma AZ. He is not a maniac, but does keep up with the flow of traffic. He reports 18-20 mpg empty and 12-14 towing. His truck is a 1988 F250 extended cab lifted 4x4, D60 SAS, ZF5, 4.10’s and 35” tires. He does have the DNE2 auxiliary overdrive but he says it is too much gear with the tall tires. The mpg stays the same, it is just more sluggish and generates higher egt’s. Another guy got within a smidge of 25mpg out of his 2wd 6.9 F250, but low 20’s was more average, and mid to upper teens while hauling. He has a fairly thorough thread on it on FTE. So 13 with a car hauler is plausible. The PSD has the advantage of computer co trolled injection, but the IDI has several points higher compression ratio and can produce some surprising results.

[Gary Lewis]

Gary, a ‘95 would be a direct injection Powerstroke 7.3, computer controlled and a major headache to transplant. It is certainly do-able, but not for the faint of heart. I’m not wanting to kick the IDI vs. PSD wasp nest, but a 6.9 or 7.3 IDI would be a lot simpler swap and would return similar results as far as mpg. Justin Anderson pulls a large travel trailer from Maple Valley WA to Yuma AZ. He is not a maniac, but does keep up with the flow of traffic. He reports 18-20 mpg empty and 12-14 towing. His truck is a 1988 F250 extended cab lifted 4x4, D60 SAS, ZF5, 4.10’s and 35” tires. He does have the DNE2 auxiliary overdrive but he says it is too much gear with the tall tires. The mpg stays the same, it is just more sluggish and generates higher egt’s. Another guy got within a smidge of 25mpg out of his 2wd 6.9 F250, but low 20’s was more average, and mid to upper teens while hauling. He has a fairly thorough thread on it on FTE. So 13 with a car hauler is plausible. The PSD has the advantage of computer co trolled injection, but the IDI has several points higher compression ratio and can produce some surprising results.

Oh, so the '95 7.3 is a Powerstroke. I assumed it was still the IDI. My bad. And I don't need a major headache. Thanks.

So, if I ever do a Bullnose diesel I think I'll start with one from the factory and do like you are doing - improve from there. And that might make a nice addition to a Bullnose collection. Hmmm:

• Flareside: Maybe an F100 with the 300 six

• Dad's F150

• Big Blue: F250HD

• Diesel F250/350

That might make a nice collection.

[Ford F834]

Oh, so the '95 7.3 is a Powerstroke. I assumed it was still the IDI. My bad. And I don't need a major headache. Thanks.

So, if I ever do a Bullnose diesel I think I'll start with one from the factory and do like you are doing - improve from there. And that might make a nice addition to a Bullnose collection. Hmmm:

• Flareside: Maybe an F100 with the 300 six

• Dad's F150

• Big Blue: F250HD

• Diesel F250/350

That might make a nice collection.

Yes, 94 was the last year of the IDI. In fact 1994 is a horrible, confusing year for diesels. Ford offered 3 different 7.3L options at once. The 7.3 IDI (naturally aspirated), 7.3 IDIT (factory turbo) and the 7.3 DI Powerstroke. Sheesh.

You have a nice list except I would comment that Big Blue and a diesel F250/F350 would be a little redundant as far as purpose. Maybe a diesel swapped Bronco?