my mileage sucks, powerstroke 7.3

Discussion in 'Trucks and Trailers' started by stumper1620, Mar 6, 2005.

  1. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    ok, i don't need to hear about duramax or cummins, this is what i got.
    I bought this truck new in nov. 02, the last of the 7.3s, 6.0s were on the lot.
    started out new with 18 and up mpg. ever since it has steadily fallen off to the point of 2 weeks ago, I went on a trip to get a new used WB, i left home with a full tank, figured i could make it there & back no problem, wrong!
    pulling my 16' trailer I got 9.7 mpg, half the trip the trailer was empty and on the return it only had 1 36"wb on it. This is the worst milage i have ever gotten other than plowing in big storms. It has been suggested to me that maybe my torque converter is not locking. if this is the case I sure dont feel a difference when driving. any Ideas, and please don't tell me to get rid of it. at this time it is not in the plan so that is not possible.
    oh ya, and during daily use with no load or trailer its still only about 14 +or-a little.
    Is this normal or is something wrong, dealer said its normal.
  2. xcopterdoc

    xcopterdoc LawnSite Senior Member
    Messages: 752

    Any other clues.. such as loss of power, hard starting ect..??
  3. LawnsUnlimited

    LawnsUnlimited LawnSite Member
    from Tn
    Messages: 15

    I have had loss of power and hard to start with crappy mileage.
  4. bsnead

    bsnead LawnSite Member
    Messages: 3

    check your fuel filter
  5. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    starts great, idles & runs out great. may have a minor power loss, i kinda think its getting weaker, seems like it requires a lot more pedal for the resultinng power as compared to prior use, as i said this is a steady decline,
    I have documented every fill up and resulting mileage as well as noting circumstances (pulling trailer, extreme cold ect.)
    I just about died when told this is normal.
    oh details, 3:73 gears, a/t super cab, stock tires and i replace the air filter at every other oil change 4k per oil change, 90% highway miles, just turning 70k
  6. xcopterdoc

    xcopterdoc LawnSite Senior Member
    Messages: 752

    In order to really pinpoint the problem you are going to have to take it to a dealer or another shop that has the proper diagnostic equipment.
    I would change the fuel filter to begin with and see if that makes a difference, if no change then off to the shop for a proper look see at all the injectors and other engine controls to include turbo charger.
  7. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    service manager at the dealer said its normal. I don't buy that and i'll take it to another dealer but, can you give a guess what should be normal mileage?
  8. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    one other question for you ford guys.
    powerstoke 100k warranty, will it cover this as long as its not a reg. mainiance item causing the problem? just curious about that.
  9. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Messages: 3,526

    A dirty air filter can really cause problems on a diesel, and the winter blend of fuel doesnt help either. Some places mix kerosene or have it refined with less wax and it doesnt have the btu's that straight diesel does. At about 25 degree's untreated diesel fuel begins to seperate from the wax and that stops up your fuel filter. Also check your air pressure in the truck and trailer tires also, in the winter lower air pressure creates more drag which means higher fuel consumption. On a site somewhere the other day, I dont remember where, A certain brand of truck is bad about the rear brakes sticking or not releasing 100% and creating enuff drag that the fuel economy is going down. Also could a trailer brake be acting up and creating extra drag?
  10. stumper1620

    stumper1620 LawnSite Bronze Member
    Messages: 1,889

    i know air is vital to dsl, used to drive big trucks,got better mileage from my frieghtliner. anyway like i say i change air filer more often than needed but i like my motor to breath good, the fuel filter is going to change tomorrow.
    thanks, still would appriciate an est of normal. this service manager is in the same auto group i used to work for. really burns me if he is lying.

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