Home Forums Gear Hunting Trucks and Four-Wheel Drives F250 Diesel Engine MPG question

No it will not. The fuel additive specifically for diesels is Lucas.

http://www.lucasoil.com/products/display_products.sd?iid=26&catid=2&loc=show

Buy it by the gallon and RTFI.

The guys on "Trucks" (a TV show) are putting an old Ford crew cab body on (I think) an 05' Dodge chassis. That will be the best "power poke" around. LOL.

I'm on my second 7.3 Excursion- the first consistenly got 20 mpg on the highway as long as I kept it at or below 2K revs. It would tow @13-14, 28' twin-engine boat. Bought it new, stock tires, sold after job loss in '04.
The '02 I have currently have has slightly larger tires (285's) that cost about 2 mpg. I haven't been able to get any better than 18 out of this one, 12 towing. Big tires cost $$$$, period. I'm going back to stock or skinnier or both when these big BFG's wear out.

I used to have access to free sump JetA, and burned it in both my Ford and Jetta TDI. Jet has had all of its lubricity removed, so I always put some lubricant back in; ashless 2-stroke always worked quite well, and is what I use now with the ULSD. Injectors are big $$$, so an additive (unless you have access to veggie diesel) is a good idea. ULSD has not appeared to cost me mpg. The killer on mpg is the winter blended fuel, with 2-2.5 less the norm.
If you're running a Ford, you could read for weeks on www.dieselstop.com on this topic.

it'll provide some lubrication for the injectors.

i'd think 2 stroke oil would be better.

I have run ATF &/or Marvel Mystery Oil in my 99 7.3 since it was new. It currently has 236K + and shows no signs of slowing down.

What does running ATF or Marvels do for you? I am curious...better fuel economy? Cleans injectors? What? Thanks.

I would assume cleaning would be the benny with some lube improvements but I'm curious too.

2-stroke oil mixed in netted pretty good results with no adverse effects. i personally run opti-lube xpd in every tank in my 05 cummins. it actually did raise my mpg 2ish. its like $42.00 a gallon and treats about 250 gallons, so over time it pays for itself by a bit, but also makes my engine run much better and quieter.

i wouldnt have believed it, but i actually witnessed it. i got back from korea and didnt think much about it and ran my truck for awhile and got to thinking why i wasnt getting the fuel mileage i normally get which is 22-23 hwy, then it clicked, i hadnt put any opti-lube in it since i ran out right before i left. so a week later i had it and 2 tanks later im back to my 22ish hwy and 18 city. granted thats being nice to it... that totally sounded like a sales pitch. lol, im not affiliated with them at all.

The tests were run by an independent company i guess. i read about it on cumminsforum.com if anyone wants to check it out. *fuel additive test*

oh, basically the fuel conditioners and what not add more "lube" to the fuel and some have detergents and such to clean out the fuel system and injectors. with the ULSD they take out a lot of the lubricating properties, which is why the older trucks dont like them at all. I.E. fuel pumps which use the diesel fuel to lube everything. this ulsd stuff just doesnt give it enough, which is why the 2-stroke did so well in the lubricity test, **but doesnt have any detergents for cleaning purposes**. oh, make sure you use the ashless. i dang near guarantee it will quiet your engines down, especially the 7.3 guys. generally 1oz to the gallon. give it a try boys & girls!

P.S. yes, it was all hand calculated and the trucks isnt totally stock...

Based on the tests done by Arlen Spicer, that is in Browningguy9's post above, I sure would NOT use Marvel in the diesel fuel. Spicer is a well known and widely regarded poster on "The Diesel Place" forums.

Take a look at the results chart on page 11, Don.

http://www.johnfjensen.com/Diesel_fuel_additive_test.pdf

yep, that's a good reference.

I had been using diesel kleen on occasion but I haven't been using anything lately.

Thinking I'll try the TC-W3 as it's been probably the most popular for many years & has proven itself even if it's unconventional.

my boss has a 7.3 with almost 300,000K on it on the open highway cruise set at 70 he has got all the way up to 32mpg. we got a superchips max tuner for it and cranked it all the way up. before that 20mpg was pretty normal, when he is pulling our skid steer he get 16-18mpg. we use schaeffer oil and also their fuel treatment.

I'm guessing the problem is with particulate and soot and it's a problem with newer rigs. It's not a problem with lubricity.

I guess I haven't had any problems personally, just an awareness of the lubricity issue with the new ULSD so I try to do the injectors a favor every now & then by "lubing up the fuel"



Bio D is actually number 1 on that chart I believe so our summer blend fuels up in my neck of the woods have got me covered.

But the bio fuels have bacteria issues so I'm sure to buy from filling stations that sell a LOT of fuel so I know I'm not getting anything that's ben around long enough to have to worry about the bacteria issues.

I guess I should probably be more worried about "dry" fuel in the winter months when it's too cold to blend the Bio.

I know a place almost as steep as that. I ran my '97 Dodge 130 miles at 50-55mph in 5th gear (most of the way)and by really filling it up at the start and not so full at the end, I got 25 once and 26mpg another time. Otherwise I got 20-21mpg on the flat.
I'M talking about going from I-90 out of Coeur D'Alene, south on hwy 3 clear into Lewiston.
We did the same test without the bountiful vs lesser fillups in our Civic and got 50 mpg.

well in his case it was across north dakota.

I have friends that have owned 7.3 Ford diesels ever since 1999 and they never got over 23-mpg period, not even when going down hill to Florida. I drove a 2001 7.3 F-250 diesel for almost 8 months and never got over 21 mpg empty savvy.

Now to say that a 7.3 is getting 32 miles per gallon is one BIG FISH STORY!!!

I don't believe thats possible at 70mph, speed being the enemy of any diesel engine, coupled with frontal area on a full size truck. Good to great mileage is achievable at lower speeds, however. I drove my '03 Cummins from my house north of Atlanta yesterday to Omaha, Ga, close to Lake Eufaula on the GA/Al state line. Slow going with the ice and fools on the road, I guess my average speed was about 50 mph. 402 mile round trip and 16.02 gallons of diesel = 25.1 mpg. (Unloaded)

pyro6999; I'm not calling you a bs'er here on the 32mpg thing...but whoever told this to you is, or doesn't know how to fill tanks and check mpg. There's a big difference between what someone else tells you and swears on a stack of bibles, and what you actually do and see yourself. What someone tells you isn't something you know, it's something you heard.
The fact is, (as I see it) from my experience of owning four different diesel pickups --- two Fords, a Chev and a Dodge --- the only way someone is going to get 32 mpg out of the truck as you described it is to do it with one heck of a tailwind, going down a steep grade for the whole test, or throwing in some other factor that we haven't been told about. Ain't gonna happen.
I like to ask guys about their trucks and sometimes some of the things I've been told by them about the power and the mileage of their trucks amounts to nothing more than a joke, but alot of them don't know enough about it to know when to stop exaggerating. This is especially true when someone is suffering from brand loyalty. Some of them don't know the difference between what they want and what they've got.
When it comes to figuring mpg, there's alot of guys who flunked math in school.

Check for "powerstrokehelp" on youtube. Guy specializes in nothing but powerstrokes. I've been watching a few of his vids - interesting really.

As to adding things to the fuel (particularly ATF for lubricity), when I worked at Peterbilt we specifically did NOT recommend doing this. Usually due to concerns over injector life and possible combustion point differences with diesel. ATF isn't designed to mix with diesel and can combust at different times(points) in the compression stroke. This came from CAT/Cummins who are in the business of selling parts to guys.

I currently work on the maintenance team for the largest trucking company in the world. We don't mix anything at all with our fuel for "added lubricity" - that's 14,000 trucks with 6 million miles a DAY put on them. If it made them last longer, better MPG, cheaper to maintain - we'd do it. Simple fact is we don't because there isn't a pay off.

Andrew,

Thank you for posting your experience. I am curious if there are any "tricks" that you do to your engines/drive lines that you could share.