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Fuel mileage.

Discussion in '6.9L IH & 7.3L IDI Diesels' started by Selahdoor, Nov 15, 2019.

  1. Selahdoor

    Selahdoor How can I help you, or make you laugh, today? Supporting Member

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    1992 F250 7.3NA E4od trans, With lockup torque converter.

    With a brand new, (Rebuilt), trans and TC.

    What do you think the fuel mileage should be?


    By the way... Before this truck sat for 5 years, the TC was not locking up, and it was STILL getting 15MPG.
     
  2. Christian9112

    Christian9112 Full Access Member

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    15mpg sounds about right for an f250 empty with normal throttle. i would imagine highway miles would be less with TC not locking up than LA traffic
     
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  3. Oldiron

    Oldiron Full Access Member

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    I just installed a Moose Jr pump and injectors and switched over to an electric l.p. on the truck in my signature. I have been getting a consistent 15.3 for daily mountain driving. In a couple weeks ill put about 400 highway miles and see.
     
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  4. Cubey

    Cubey Full Access Member

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    My 87 F250 6.9 NA C6 3.55 gets about 14-15 hwy with a short, light camper (just a cap, not a slide in) with a rebuild trans a few years ago, dunno how old the IP or injectors are. Engine likes to use oil but not "excessive" for an IDI, I guess.

    IMG_20170529_101809.jpg
     
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  5. Oldiron

    Oldiron Full Access Member

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    This mod will drop you down to about 6.6mpg. Lol 1016191057.jpg
     
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  6. Selahdoor

    Selahdoor How can I help you, or make you laugh, today? Supporting Member

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  7. Cubey

    Cubey Full Access Member

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    Whatever that is.... I don't even get that bad in the motorhome! Except maybe with winter blend fuel while climbing mountains. It gets about 9-9.5 hwy in summer. It's getting about 8-8.5 right now. Could be the new fan clutch hurt mpg too, it dropped immediately after putting it on, but it coincided with about when they start using winter fuel, late Sept/Early Oct.
     
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  8. gandalf

    gandalf Senior Member

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    What axle ratio on the truck? That will affect your mileage.
     
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  9. Oldiron

    Oldiron Full Access Member

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    It was the stock intake tube. I was hauling a 35's 5th wheel up the pass. I dont know if it happened on a down shift when the turbo spooled, but it sucked it inside its self. Huge drop in power and mpg.
     
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  10. Enginerd

    Enginerd Registered User

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    Sounds like you really were hauling to suck a tube inside itself! That's impressive
     
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  11. Enginerd

    Enginerd Registered User

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    I have 93 n/a e4od 4wd and a 3.55 gear, and I've been getting 16-17. I also have the front brakes dragging a little more than they should though. I'll be replacing the master cylinder next. I just straight piped it so we'll see if the mpg bumps up. But I do feel bad with that straight pipe at 4:30 in the morning going to work so I don't know how long it will last...
     
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  12. Jason1377

    Jason1377 Supporting Member Supporting Member

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    Not to sound dumb but how do you go about figuring milage out? My rig is a stock n/a e4od automatic 2wd 1993.5 f250 stock rims/tires and when both tanks are fuel I can go roughly 375 miles using both tanks not letting either one hit the last white line before it meet the dreaded empty red line.

    Sorry my punctuation sucks spelling sucks for a fat fingered dyslexic man
     
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  13. Selahdoor

    Selahdoor How can I help you, or make you laugh, today? Supporting Member

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    To get somewhere close to knowing what your fuel mileage is...

    First, you have to be sure your odometer is correct.

    Second, you have to fill the tank up the same way, every time. In other words, hold the filler in exactly the same place. Hold it all the way open. Or part way. Etc. Stop the first time it shuts off. Wait till you know the fuel is pretty much to the top of the tube. Etc. But do it the same, every time.

    Now... Go fill up. Write down the mileage.

    Drive.

    Every time you get fuel, fill it all the way up. (Remember. Do it the same way every time.) And write down the mileage.

    Figure out how many miles you drove since the last fillup. Divide that by the amount of gas it took to fill up.

    After several fillups, you'll be able to determine an average. That is your fuel mileage.
     
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  14. Christian9112

    Christian9112 Full Access Member

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    odometer after first fillup (Example, 1,000,000) keep note of this
    Odometer after second fillup (example 1,000,140)
    From the first fillup to the second fillup you have driven 140 miles.
    Second fillup gallons (example 10 gallons) it would say at the gas pump. keep note of this
    second fillup miles - first fillup miles = total miles driven. (140 miles)

    gallons used for the 140 miles you have driven = (10 gallons) your tank doesnt have to be empty. just keep note of how many miles driven and how much fuel was used.

    miles driven (140) divided by gallons used (10 gallons) = 14 miles per gallon.
     
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  15. nostrokes

    nostrokes Full Access Member

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    91 ext. Cab 4X4 4.10:1 axle turbo e4od I get around 13-15 depending on how my leg feels..
     
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