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Miles to Empty dropping rapidly

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Su Mo, Mar 31, 2023.

  1. Su Mo

    Su Mo Junior Member

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    Hi Guys,


    I have question about a used vehicle I test drove today and I’m researching whether

    Or not to buy it. I test drove below two vehicles which are pretty similar:


    Vehicle1:

    Year/make/model: 2013 Toyota Avalon xle touring HYBRID

    Mileage: 85k


    Vehicle2:

    Year/make/model: 2013 Toyota Avalon Limited HYBRID

    Mileage: 82k


    I’m sorry this could be a general question and this is about an Avalon and not a Prius. Y’all are so geniuses here that inclined to post this question here I didn’t find a brilliant community as this elsewhere. Please help me it will be a huge help.


    Both the Toyota dealerships told me that these cars were traded in by older couples in there 70s. The vehicle condition both physically and drivability is too notch just as new car. Very neat! No doubt there at all. Of course, all the warranties including Hybrid warranty has expired.


    Question:

    One exact same thing I noted during the test drives is about the gas “miles to empty” numbers on the driver’s display. It dropped significantly while I test drove the cars.

    For example: the Miles to Empty was at 310 when I got into the car and I hardly drive 5miles and it dropped to 292 miles to empty. This happened with both the cars.


    On the contrary, Under the Info Apps for showing the fuel consumption average, the best it was showing was 39.5mpg.


    I’m very confused about this that how it can drop so rapidly. I out the cars in EV mode and did 2-3 rounds of the dealership and it drove well until I punched the gas pedal over 25mph.


    Please let me know. It will be a huge help. Thank you!
     
  2. Su Mo

    Su Mo Junior Member

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    Both the cars were traded in two weeks ago and have been sitting there for customers. If this matters.
     
  3. Grit

    Grit Senior Member

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    One time I filled up my PRIUS and it showed 629 miles to empty. Got on the highway and drove 75 mph against 15 mph wind and rain for 25 miles with windshield defroster up to 80%. DTE was 560 miles after the drive, I was frustrated because miles was not accurate and went down very rapidly also
     
  4. Su Mo

    Su Mo Junior Member

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    Is it stable now?
     
  5. fuzzy1

    fuzzy1 Senior Member

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    He is being sarcastic. describing a situation where high fuel consumption causes the distance figure to plummet rapidly.


    Miles To Empty is a very simplistic forecast, assuming that MPG for the miles ahead will be exactly the same as the recent miles behind. But while that assumption is someties close enough to be useful, other times it is wrong, by a lot, sometimes causing the distance estimate to drop rapidly.

    Don't read too much into the number or its changes compared the odometer. It means much less than you may think.

    MPG varies enormously with speed, mountain climbs vs descents, wind speed and direction, rain, outside temperature, engine warmup condition, traffic conditions, road surface texture, weight, etc.

    If the previous trips were long drives at moderate steady speeds in warm (not not) weather with a tailwind, i.e. high MPG conditions, the distance to empty forecast could be an anomalously high number based on rosy MPG expectations. Then, if you start up with a stone-cold engine that needs to be warmed up, then drive a short distance (5 miles counts as short) with aggressive acceleration, stop and go, with hill climbing, in foul weather, then MPG will be poor, and Distance to Empty may drop a lot more miles than you actually drove.

    In the opposite situation, going from low to high MPG conditions, the number can drop unusually slowly, much less than the odometer is increasing. On my other-brand car, the distance number can even increase as I glide long distances downhill, as it assumes that the downhill glide can go forever. But the Prius' internal formula forbids it from increasing except when fuel is added, forcing it to decrease at least 1 mile for each 2 miles driven. I don't know any details about the Avalon's internal formula.

    It isn't a problem with the car or the reading, but a reflection that the distance forecast was based on different past driving conditions than you are experiencing now, and it needs to adjust.

    It often doesn't mean very much, so don't overthink it. Don't count on getting the displayed miles, make sure you have a good safety margin for unexpected conditions.
     
  6. bisco

    bisco cookie crumbler

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    because the cars were owned by older couples, the mte was high. during your test drive, one, the engine was cold, and two, you were probably a little more aggresive than the older couples.
    the drop is simply a calculationof those two factors.
    i wouldn't worry about it.
    you'd be well served to reset the average mpg meter and go for a 20 mile test drive under various conditions and see what they return.
     
    Montgomery and Salamander_King like this.
  7. Grit

    Grit Senior Member

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    Funny you should say old people because spent 6 months hunting for the trim and interior combo, car salespeople kept telling some grand pa or grandma previously owned it. About 90% of the Prius I test drove with the saleslair with me in the vehicle.
     
  8. CR94

    CR94 Senior Member

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    In short, don't be so naïve as to take the car's miles-to-empty estimate seriously.
     
  9. Su Mo

    Su Mo Junior Member

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    Vehicle1: Year/make/model: 2013 Toyota Avalon Hybrid xle touring mileage 86k

    Finally I bought the vehicle1 I bought yesterday. I bought this because my Prius 2010 gasket failed and my gasket replacement went south. After the replacement, when I started the car it start but make noices dud dud dud dud and the. Shots off oil and coolant leaks down the engine. I will redo the job again or do you know if I can find a used 2010 engine for cheap like for $500?
     
    bisco likes this.
  10. bisco

    bisco cookie crumbler

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    check LKQ