Fuel Milage Gets Better as Temps Go Up

Discussion in 'Engine, Fuel and Exhaust' started by Bud White, Jun 5, 2012.

  1. Bud White

    Bud White Well-Known Member Retired Moderators

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    Ok this year after it sit all winter with not mods due to a shoulder injury . my mileage on road king was bad. I had to do a firmware up grade to my thundermax tuner forced by the maker.

    my mileage was 33-35 way down from last year at 42-44 so i tried riding it and the auto tune came up but not great .

    So fast forward to memorial weekend I got 38-40 2 up on the way down after adjusting tuneing etc great i can dig that 2 up but cant do better alone..

    Then the whoppers 70 degrees 38-40 ... 80 41-42 low 90s 43-45


    i did get 54 2 up in the mountains at about 98 degrees but think its fluke .. no pinging and not running super hot feelin about normal for 90 .


    so i came home checked the tuner not codes

    after 2 days of sitting the head temp was 72 out side air 78.8 and the air temp 93.5 huh? so i checked no shorts or anything i could find. ordered new sensor air temp in garage 64 head temp 63 air temp old sensor 83 new sensor 84 ... what am i missing service manuals are thin .. i would think if outside temp is 64 the air temp should be close..
     
  2. Hoople

    Hoople Account Removed

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    When you say "air temp" do you mean air Intake temp?
    I agree, it sounds like it should be closer to actual temp. I know in the HD manuals, there is a resistance vs temp chart for sensors. You may just want to check the resistance of the sensor with a good meter while at a specific temp.
    After that I would check the reference voltage and see how close it is to 5.000 volts. I have seen 5.0 volt references measure 4.50 or 5.25 volts. After that I would hunt down the calibration constant. It's got to be somewhere within the program. It may be hidden from view but it's got to be there somewhere.
     
  3. Bud White

    Bud White Well-Known Member Retired Moderators

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    yes the air intake temp . i did check the sensor and had a new one in hand same temp showing .. i didnt check the voltage yet need finer probes to do it while hooked up .. the question is where would the calibration constant be ?
     
  4. Hoople

    Hoople Account Removed

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    The TMax people should be able to get that straighten out either with a firmware patch or the steps needed to calibrate the intake sensor to the visual display. Is this the first time you have noticed this error.
     
  5. Bud White

    Bud White Well-Known Member Retired Moderators

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    yeah cuz i was looking for a problem with fuel it doesnt trip a trouble code
     
  6. HermitKing

    HermitKing Member

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    Maybe not relevant..
    Trip to Mom's house. temps 60-75 Mileage 39mpg oil 50wt dino (to quiet lifters..lol)
    Same road temps 85-95 44mpg 50wt
    Same road temps 75-85 47mpg 20w50 Spectro synthetic
    Just the thickness of the oil seems to make a big difference in my mileage.