dismal fuel milage even cruising on highway

[69oiler]

thanks Russ.

i have 2 local options for fuel. Chardon Oil sells LSD, the 500 ppm stuff. this is what i use most of the time.

GetGo sells the USLD. i only use this when i can utilize Fuel Perks, for those who dont know for each $50 you spend at Giant Eagle you get $.20 off per gallon up to 30 gallons. so i let my tank get low when i have fuel perks saved up.

regardless, i have been getting basically the same milage on both fuels. i have been toying with getting Biodiesel delivered to my house, i have a tank on a stand that i need to recondition that i would use. maybe i'll find that Bio station next time i'm in the city.

 

[justblowin'smoke]

if i can keep my foot out of it with the low sulfer fuel i get 18-19 empty doing 60-65. the 500 mile trip i took back in sept. i got 16 doing 75-80 and 200 miles was pullin a very well built 14,000lb trailer empty it weighed some where around 3000lbs im guessin and that was without functional cruise control

 

[69oiler]

i just performed a 2 step engine revitalization with a product by Mighty auto parts given to me by Nick (double s diesel). i was going to straight pipe the truck first but after looking at it it's not a simple task like it was on my '86 because the pipes dont line up the same way. so i decided to try this potion with my stock exhaust with muffler and convertor. i sprayed the stuff into the intake and put the other stuff in the fuel tank. we'll see what happens.

 

[justblowin'smoke]

My buddy has a '99 F350 SRW 4x4 and he gets about 10. I've got my '86 F-350 Dually 4 sp. and get about 13. Maybe it was the year?

my early 99 as in bulit 5/98 gets 18 and im not that light with the right foot so i don't think its the year

 

[Dieselmaster]

My Early 99 CC SWB LB Automatichad a 6.5" lift, 37" tires, 3.73ls.... and I consistently got 12-13 in town and 15-16 on the highway.

The only time I saw a big difference in fuel mileage was when I would run the chip on the #4 setting which was programmed for 120hp.... You couldn't touch the go pedal without a black cloud belching from the tail pipe.

 

[Double-S-Diesel]

Rob
awaiting results.
Ill take a looksy and see if I have a factory cat delete,
I know I have a tail pipe already welded with a straight pipe.
Nick

 

[Agnem]

Rob, dumb idea, but maybe something worth a try. Find a hill on a quiet road, and stop at a marker. Put the truck in neutral and let it roll until it comes to a stop. Now do that with your IDI. Which one rolls farther? Just curious if rolling resistance, tires or some weird thing could be factored in this way. I know I've been getting 2MPG less since they switched to ULSD.

 

[69oiler]

Mel that's a very good idea. I'll try it and post the results next time i have my IDI out.

Nick i haven't done the math yet but i'm almost sown to "E" with the tank i have the additive in. trip meter says 388 or thereabouts. i do think ULSD is part of the problem.

 

[69oiler]

12.9 mpg

i fueled up and added a dose of Power Service grey bottle. it's tough to get excited about this PSD unless i can figure out how to get decent milage out of it. i hate to keep throwing all my money at this truck.

Nick i dont have the money right now for a 4" exhaust but let me know what you want for your straight pipe setup. i think my exhaust system may be the problem. if that aint it i may rethink this whole thing.

 

[tonkadoctor]

Rob, I had a local exhaust shop just chop the muffler off of mine and weld in a piece of 3-1/2" straight pipe $70.

Not sure if you'll even have a Cat on the '99 superduty, my 2000 didn't.

 

[69oiler]

mine does have a cat.

 

[tbirdfiend281]

the ULSD is evil, i have heard significant miledge losses from a few diesel customers, some not so much as others, but for a little bit people where definitly complaining about it, but your miledge is really low, are you 100% sure nothing is the matter with the truck?

 

[69oiler]

i'm not 100% sure of anything. my best guess is that my exhaust system is plugged up. money is tight right now or i'd get the 4" system i want. i may have a straight pipe installed on the stock system but if i go to the trouble i'd rather save up and get the 4" and be done with it. after our vacation in July i plan to bust ass and make some cash.

other than that the truck runs fine. i guess i could have it checked for codes but it's running fine and no CEL so why waste the money.

a new 4" exhaust can only help it's resale value

 

[Russ]

Rob the guys over at SDD are talking mpg. It looks like you're not alonehttp://www.superdutydiesel.com/forums/99-7-3l-powerstroke-engine-drivetrain/11453-mileage-other-7-3s.html

 

[Double-S-Diesel]

hell dont feel bad. seems like it took me way too much fuel to go to austin lake and back home.