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Something's Wrong

Discussion in 'Gen 2 Prius Fuel Economy' started by Don Felts, Aug 20, 2024.

  1. Don Felts

    Don Felts Junior Member

    Joined:
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    Vehicle:
    2008 Prius
    Model:
    III
    I've never posted much once or twice. When I had a problem. Thanks guys for the support. I have a 2008 Prius base. Has over 315000 miles on it. I've driven it for years. I commute 180 miles 4 days a week. My average has been 42-47. Depending on tires. My tires are pretty worn. Goodyear Fuel Max Radials. Bought them in July 2022. They have over 70000 miles on them. Probably 80000. You know as tires wear mph goes up . I used to use Bridgestone Ecopia EP422. The Bridgestones. Didn't last very long. They could blow out anytime. I pumped all 4 tires to 42#
    Yesterday I filled up at Murphy's. I noticed the fuel smelled very rich and strong. More than usual. I drove 90 miles. I noticed my gas didn't change much. I stopped at Kroger to fill up. Kroger fuel cost less $2.67 a gallon. The tank held $2.00! 3 quarts! I drove a Honda Insight for many years on the same commute and the best MPGs I ever got was 75 MPSs. I was drafting a semi with a 15 mph tail wind. I can't believe it went 90 miles on 3 quarts. That's a little over 100 mph. It had to be the fuel. Nothing else explains it. I'm certain I put low test in it. I've never put anything else in it. I guess there is a chance the the trucker got the fuels mixed up. I've always believed the Prius won't do better on hi test. I've never even tried it. If I'd known I could get over 100 MPGs using premium I would have. What do you guys think? Has there ever been similar experiences?
    Thanks for looking.
    Donald Felts
     
    #1 Don Felts, Aug 20, 2024
    Last edited by a moderator: Aug 21, 2024
  2. MAX2

    MAX2 Member

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    2007 Prius
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    Try refilling with higher grade fuel and measure the new consumption during the trip.
    If consumption changes for the better, then switch to new fuel.
     
  3. bisco

    bisco cookie crumbler

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    that is the vaguest post i have ever read regarding how to determine mpg and its causes
     
  4. fuzzy1

    fuzzy1 Senior Member

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    My first suspicion is that this fuel pump may have cut out earlier than the previous fuel pump, producing a very inaccurate MPG calculation.

    What MPG was the car showing?
     
  5. Don Felts

    Don Felts Junior Member

    Joined:
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    Location:
    Mississippi
    Vehicle:
    2008 Prius
    Model:
    III
    I can't believe it. I have a lot of experience with the Prius. More than 180 miles a day. 4-5 days a week. 52 weeks a year. I filled up. Drove over 100 miles. I was surprised that the gas gauge showed very little consumption. But I fill up every day so it doesn't matter. The fuel consumption meter said I got 46mpg. When I filled up it held $2 at $2.76 per gallon. About 3 quarts. I drove a 2001 insight for 5 years on the same commute. The best I ever got was 75. Drafting a semi with a tail wind. And Bridgestone fuel saver tires. I'm not a newbie. I've been doing this for over 15 years.
    I'm a disabled veteran. I typically go to the VA hospital 5 days a week 52 weeks a year. That's why I can't figure out what's wrong. Beats the hell out of me. (n) My Prius got over 100 mpg. I made the same trip today and I got 45mpg. IT may not happen again. I certainly don't know how to repeat it.
     
    bisco likes this.
  6. Don Felts

    Don Felts Junior Member

    Joined:
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    Location:
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    Vehicle:
    2008 Prius
    Model:
    III
    I guess it's possible the fuel pump cut off early. It's happened before. But I checked it. I can't afford to run out of gas on the interstate. I have cancer. It's too easy to be sure to run out :(
     
  7. fuzzy1

    fuzzy1 Senior Member

    Joined:
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    Location:
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    Other Hybrid
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    When you refill after just short distances, in this case just 90 miles, inconsistencies in the fuel pump shut-off point get magnified when making MPG calculation. More accurate MPG calculations require averaging over long distances with multiple full tanks of fuel.

    The fuel consumption meter has its own issues for completely different reasons. But because it shows a normal consumption for this trip segment, I'd write this off as an abnormally early fuel pump cutoff.

    Check your fuel logbook. Did either the refill immediately before, or the one immediately after, show an abnormally low MPG?