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Poor gas mileage/tranny not going to high gear?

Discussion in 'Gen 2 Prius Technical Discussion' started by dawint, May 16, 2011.

  1. wjh308

    wjh308 Junior Member

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    The "variation" of the eCVT depends on MG1 to determine the ratio of torque the ICE produces compared to MG2. I've discovered the Achilles tendon of the Prius... Sustained steep hill climbing. If Mg1 cannot spin to control the ratio between MG2 and the ICE, the engine will appear to be in the "lowest gear" in a conventional car. IE, the ICE is running fast and the car is moving slowly. So when your climbing a steep hill, the battery will be drained quickly and once it is drained, the ICE has to do double duty of charging the battery AND moving the car,(at a very high rpm) and there is no way around very poor gas mileage when this happens. I experience this when I visit Tilden Park in Berkeley, driving up the steep hills. Prius does not like hills.
    As for your gas mileage, check your tire pressures.


     
    SFO likes this.
  2. cwerdna

    cwerdna Senior Member

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    Since you didn't answer the questionnaire and don't think you provided results of your 12 volt after it's sat overnight, here are some other possibilities:
    - commute changed to one that's unfavorable to mileage (esp. short ones in city driving)
    - your above tires since they're larger, might be (likely are) of higher rolling resistance and might be introducing odometer error
    - alignment
    - tire pressures
     
  3. F8L

    F8L Protecting Habitat & AG Lands

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    The 17s always drop mpg in a genii by approximately 4-6 mpg.
     
  4. dawint

    dawint Former AudiWorld Member

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    The battery is 12.3 at rest with brake on ......

    I'm going to switch over to winter mode soon (OEM size wheels and tires) I'll bet everything goes back to "normal" ... I had no idea that the change over would do that ... didn't on my A4 .... I miss my A4 :(
     
  5. seilerts

    seilerts Battery Curmudgeon

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    Surely you don't miss the high cost of maintenance and repairs? My impression of Audi is that they are status symbol cars with an expected lifetime of the 5 year trade-in cycle.
     
  6. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    SFO and F8L like this.
  7. dawint

    dawint Former AudiWorld Member

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    Maintenance was more expensive ...timing belt etc ..... that I don't miss

    I got a Wednesday car which did not require much repair ....

    It was a 98.5 so it didn't have a lot of the "upgrades" DBW etc ....

    I sold it at 164K miles ... and it still looked great ....

    To me it wasn't a status car ..... just a better option than my Exploder at the time

    It was more mod friendly .... (to me anyway)
     
  8. V8Cobrakid

    V8Cobrakid Green Handyman

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    i'd blame your tires and call it all normal....

    how long have you been running 17's... and what brand is the rim? if it's any heavier than a scion tc rim.. i'd still call it all normal...

    my first thought was ignition coil.. but you said it runs smooth and has power (which contradicts your initial report)
     
  9. V8Cobrakid

    V8Cobrakid Green Handyman

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    btw.. i would take your battery down to a place and have it load tested.. everyone loves to read the voltage but the majority of times it's not really giving out that good of numbers... or the car is feeding it... or.. well.. there is no real load when you test.. many things.. it's cheap to have o'reilly or auto-zone or whichever place is near you test the battery.
     
  10. dawint

    dawint Former AudiWorld Member

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    I agree .... However I changed back to my 16's and while there is a noticeable difference in rolling .. my ICE is still coming on at inopportune times!
     
  11. dawint

    dawint Former AudiWorld Member

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    Elbrus wheels with Hankook summer perormance .... running since last April ......
     
  12. cwerdna

    cwerdna Senior Member

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    You may have incurred mileage changes as a result of wheel and tire changes on the A4 but dismissed them as being "small". See http://priuschat.com/forums/other-c...eage-no-its-your-gallonage-really-counts.html.

    Besides the rotational intertia, heavier tires and wheels, most likely higher rolling resistance, odometer error, there's also the larger contact patch.

    You might find Tire Tech Information - Tire Rolling Resistance Part 3: Changes to Expect When Switching from Worn-Out to New Tires, When Round and Black Becomes Lean and Green and When Round and Black Becomes Lean and Green interesting.
    Without more details, such as by answering the questionnaire, we can only guess and point to some of the known causes in your case.

    If you want to monitor what's going on, you should buy something like ScanGaugeII : Linear Logic - Home of the ScanGauge or use other similar tools that plug into the OBD2 port.