Poor fuel mileage

Discussion in 'Ask An Owner Operator' started by Newbieboy, Nov 1, 2020.

  1. Newbieboy

    Newbieboy Light Load Member

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    Hello ... i need help to understand what is going in with my freightliner cascadia dd15.
    Ive 2 diesel tanks take about 180 gallons. I used to get around 1200miles in 160 gallons. Since this week my millage dropped to 850-900 miles in 160 gallons.
    Already checked fuel tanks they not leaking.. something else is going on.
    What you guys think which part has failed in my truck?
     
    Last edited: Nov 1, 2020
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  3. Spyro2112

    Spyro2112 Medium Load Member

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    Change filters, start getting fuel elsewhere, might have picked up algae
     
  4. cjb logistics

    cjb logistics Heavy Load Member

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    Kind of a loaded question!
    How long have you had truck to map mileage? Did you change your driving habits, ie terrain, location, winter, wind... weight,,, running 85,500 now with a spread axle hopper running hills with 30 boost on turbo! Get my drift here. If I throw on the milk wagon vs hopper I get 2 more miles per gal. Sometime less on Friday evening if i'm running behind to get back home, tend to lay on the fuel pulling hills.
    Did you change to a different wagon? "Tanker to something square"!
    Tire size the same?

    Ok answer these then people will give some insight on what may be an issue with the engine.
     
    magoo68 Thanks this.
  5. Newbieboy

    Newbieboy Light Load Member

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    I am a dry van.....I always monitor my millage 160 gallons 1200 miles..got good year tires on steer same size. . I drive east coast to west coast under 30k... Right now ive 26k weight. I bought 510 gallons this week drove 2700miles.

    no idling no apu.. all ive a bunk heater
     
    Last edited: Nov 1, 2020
  6. cjb logistics

    cjb logistics Heavy Load Member

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    So 5.2 mpg vs your previous 7.5 mpg. Cold weather set in idling more?Still on the same route back and forth, give or take on your traveled path?
    What's your gauges telling you on engine, running more boost then normal (or less if you have a leak in CAC), temps running higher, 'did you take your cylinder temps again with your temp gun to see if they have changed'?
    Time now for the truck Detroit guys to get on with there knowledge.

    I'll just stick to my knowledge of the 8v92 with a 2-1/2 to 1 twin disc clutch turning up about 2100 naturally aspirated. Dang find boat motor, leaked oil everywhere, but I digress; and had a flash back of my youth.
     
    Coffey and Dale thompson Thank this.
  7. Newbieboy

    Newbieboy Light Load Member

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    No idling got webesto bunk heater. Same route.. same refueling stations. All temps are normal... no codes on dash. No leaks

    Failing fuel valve can increase fuel consumption?
     
  8. Dave_in_AZ

    Dave_in_AZ Road Train Member

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    Air filter.

    And are you in extreme wind?

    That is definitely a dramatic drop off.

    Sometimes a sensor in the aftertreatment goes out of whack that will cause problems like this as well.

    Wind will absolutely knock the snot out of your mpg though.
     
  9. Newbieboy

    Newbieboy Light Load Member

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    Driving 2013 cascadia with no def... i guess soot wont hurt me... there is no wind.

    going for a oil change will replace all filters..
    my last fuel refill was 129 gallons on 700 miles.
     
  10. AModelCat

    AModelCat Road Train Member

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  11. Newbieboy

    Newbieboy Light Load Member

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    Loosing +2mpg on a Gallon.isnt it too much to loose on winter fuel? Last year i lost around 1mpg.
     
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