Fuel mileage

diamondusmc · Jun 28, 2005

Hello all, just wondering if anyone had any info on what to expect for my fuel mileage. I have a 05 F650 with a 48" sleeper and 20ft box with a five speed auto allison.. I thought I was averaging 7-7.5 when I was driving the truck. I now have a driver in it that claims the truck seems to be eating fuel. From what the driver told me and for the mileage and fuel that was claimed to have gone through, I estimated the fuel mileage to around 4MPG. Now that being the case I don't think I can remain in business long with this kind of mileage. I assume something is wrong although the driver claims there is no excess smoke coming out indicating excess fueling. I currently have the driver coming back so as I can have the truck checked out. Thanks.

redytrk · Jun 28, 2005

>Hello all, just wondering if anyone had any info on what to
>expect for my fuel mileage. I have a 05 F650 with a 48"
>sleeper and 20ft box with a five speed auto allison.. I
>thought I was averaging 7-7.5 when I was driving the truck.
>I now have a driver in it that claims the truck seems to be
>eating fuel. From what the driver told me and for the
>mileage and fuel that was claimed to have gone through, I
>estimated the fuel mileage to around 4MPG. Now that being
>the case I don't think I can remain in business long with
>this kind of mileage. I assume something is wrong although
>the driver claims there is no excess smoke coming out
>indicating excess fueling. I currently have the driver
>coming back so as I can have the truck checked out. Thanks.

I would suspect your driver either has a lead foot or is stealing from you.

If this is not the case you need to have the dealer check it out.If the engine checks out. Look for the wrong gear ratio in th rear end.

Marty · Jun 28, 2005

Have your driver pay for fuel. This might increase the fuel mileage.

diamondusmc · Jun 29, 2005

Thanks for the replies guys. I am going to have the dealer check it out. Also, I already have the driver paying for the fuel. I definitely will find out what's with the mileage. Driver is still remaining profitable. Driver is just trying to keep loaded and eventually work her way back to me (Michigan). Then the truck will be going right to the Cat dealer for a checkout. I imagine the rearend ratio should be correct. I read in the manual somewhere that if you are going at 60MPH, your rpm's should be around 2000RPM; this seems to be what I'm getting. And as for the driver being lead footed, that could be possible I guess. But, man when I drove the truck, it seemed that it woould not allow you to lead foot it. It would just take off kinda sluggish anyway. I mean for a truck this size it seemed to take off alright. Well, as soon as the truck gets back it'll get a thourough checkout, cause I know it can get better mileage than 4-5MPG. Thanks, again for the replies.

Loose_Cannon47 · Jun 29, 2005

If you were getting 7-7.5 and your driver is only getting 4-5 mpg, then it's NOT the rear gears, unless someone swapped it out while your driver was sleeping...

Loose

tazman · Jun 30, 2005

What engine are you running in this unit ???

You know F-650's can be equipped with 6.0 Powerstrokes....given the rash of injector issues I see with these engines..could be your trouble......

If it is an "05"...have him stop in any Ford Commercial truck dealer and have them diag the unit...It should not be a chargeable item charge

cat and Cummins engines in these units have separate warrantys....check out what you have ....

Thanks

"The Beast in the East"

tazman · Jun 30, 2005

Sorry I missed your quote about the CAT dealer...I'll assume that what you have a CAT 3126E unit What HP rating ?????

Cat has some recalls out as well......get to a dealer
Your warranty is 3 years or 3600 hours....should be a no charge checkout....

Frank in Pa.

"The Beast in the East"

Broompilot · Jul 6, 2005

I had the same problem but not that low. Get to the Allison Dealer, and Cat Dealer. Change that 5spd over to the 6spd its computerized but the two manufactures must run a spec sheet.

The rpms will drop by 17% as it did for me. The noise level alone was worth the idea. The rpms are just to high at 55mph up to 65 or faster.

2nd spend $200 and get the front end rebalanced-aligned-and the Tires Trued, should not be much more than that. Your gona ask Why? The truck is not pulling and tires are not wearing at all. No tire is perfectly round until it has been Trued on the rim that it is mounted on.

I did all the above, plus began using a fuel Booster, dropped my expressway speeds to no more than 63. I went from 8.8 mpg (BEST) some tanks were even lower, to now my highest was 11.2 but closer to 10 on the nose.

I can not point to anyone thing but I give the 6spd the most credit. I am saving a ton of $ and getting hundreds more miles between fill ups. Do not worry anymore in VA, or OH that I can fuel up there and head up to CT, NH etc.. and make it back without the worry of buyiing fuel at .30 more a gallon in those states even if I only add 30-40 gallons up there. I now avoid all fuel purchases in those Highway robbery States.

diamondusmc · Jul 20, 2005

Hey all, had the truck checked out. The Cat shop gave me the whole low down with the computer printout. The truck is averaging 8.8 miles per gallon. My driver was not telling me that what was considered all the fuel was still having a quarter tank left, so this through my calculations off. And yes I have the 3126E engine with the five speed in it. Now I don't think that swapping out the 5 for a 6 speed would be what I want to do right now due to the big money it would probably cost to do so. Although I probably will do the tire truing and balance when my driver returns the next time. Thanks for the replies.