My MFD mpg ave is down about 10 mpg after last fill-up

Discussion in 'Gen 2 Prius Fuel Economy' started by 93dawg, Oct 17, 2014.

  1. 93dawg

    93dawg Junior Member

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    Long explanation so please read carefully and thanks for any help anybody offers.

    I filled my tank up a few days ago and now I have a enough miles on this tank that the mpg should be holding pretty steady and my average is down about 10 mpg from what it usually is. It is varying up and down a little around 38 mpg when in the past it has been varying around 48 mpg or more when driving around town which is what I am doing now. I had driven 353 miles on a trip and it took 7.00 gallon to fill it for 50.40 mpg. I bought gas in Oregon where it is not self serve and told the guy who was gassing my 2006 Gen II Prius how hard it is to get the tank filled and that he needed to pump on auto as slow as it would go which he did. I had taken the gas cap off a few minutes before he started pumping. I also told him it should take around 6.5 gal to 7.5 gal and that he might have to feed it in slowly by hand which he did after it shut off the auto feed. I guess I wasn't paying enough attention because he hand fed it slowly for several shut off clicks without me realizing it was clicking off until I finally realized it had shut off several times so I told him that was enough. When I turned the power on a big red triangle came up and then went off after a few seconds. I didn't notice any other light alarms light up. So after that I am watching everything real close. Right away I notice my mpg average on the MFD is down. Of course I by now know that it varies all over the place when the first miles are put on but after putting enough miles on it that it should have started steadying up I notice that my average is down to around 38 mpg from the usual around 48 mpg or more. I am assuming that too much gas was put in but the mpg for the trip was about what I was expecting.

    Did I damage something? Will my mpg average come back up to what it was before? Anything else I should know other than I am an IDIOT...haha...

    And oh yeah I hate this bladder gas tank...
     
    #1 93dawg, Oct 17, 2014
    Last edited: Oct 18, 2014
  2. bisco

    bisco cookie crumbler

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    i think you may have accomplished what we talked about. probably worth checking your carbon canister. what i don't understand is how toyota managed to sell millions of gen II's without the bladder becoming a bigger issue than it was.
     
  3. bisco

    bisco cookie crumbler

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    or it could just be a coincidence, and your 12 volt just bit the dust.
     
  4. 93dawg

    93dawg Junior Member

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    Bisco my 12 v battery is brand new so I don't think it is the problem. When I bought this car a couple of months ago replacing that battery was one of the first things I did.

    Maybe my bladder is expanded eh?. At 82 I need an expanded bladder...haha...

    I just wish somebody from a foreign country would ship me a bladderless tank because I would sure try to make the change. I don't live in California so I could stand t0 sniff a some gasoline fumes...haha...

    I'm thinking maybe I will gas up at about 3 pips except for maybe when planning on a long trip for a while and see if that helps keep the tank expanded.
     
    #4 93dawg, Oct 17, 2014
    Last edited: Oct 18, 2014
  5. 93dawg

    93dawg Junior Member

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    Any more ideas anybody???
     
  6. uart

    uart Senior Member

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    Yep, make sure that the gas cap is on tight and just drive it. I don't see any long lasting harm that is likely to have been caused by that gas station incident. Unless it was some kind of coincidence, where something else more serious just happened to go wrong at the same time, then I think it will resolve itself without intervention.

    Lots of people notice temporary loss of fuel economy for all sorts of reasons. Often times it just sorts itself out after some amount of driving. I'd start worrying if it's still the same after a going through a few more tanks of gas.

    BTW. How many miles have you driven since this fill up?
     
  7. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Avoid Oregon?

    Seriously, full service stations are a sore point for me. Our municipality is one hold-out that doesn't allow full serve. I've tanked up in neighbouring communities for about 25 years now...

    The second gen bladder tank sounds like a real pain.

    Bisco might have something, regarding the carbon canister etc.

    Kinda reminds me of Oahu. Maui, no problems. But Oahu: try paying for gas with an out-of-state (out of country, in our case) credit card. The outcome is always awkward, involves a walk into the station, explaining what pump you're on, entrusting the attendant with your card. I guess that happens to every occasional tourist that visits...
     
  8. 93dawg

    93dawg Junior Member

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    I just went out and checked the mileage and I have 45.4 miles on Odometer since the last gas up that I have been talking about and I clicked the gas cap a couple of times to make sure it was on tight. Thanks for the suggestions uart.

    I have worked hard to try to get the mileage average up. I think maybe part of the problem may be the in town trips were all too short and not much driving time after warm up. Maybe I will see if I can locate a good 20 mile or so drive where I can drive around 35 mph and see if I can work the average up some. I am not at home but in Southern Oregon where I am not all that familiar with the roads. We will see...

    And like you said maybe it will sort itself out after a couple of tanks of gas...

    Mendel normally I am in Washington State where we pump our own gas even though only just across the Columbia river from Oregon and about 45 miles from Portland, OR so I don't very often buy gas in Oregon... Sorry about you having problems paying for gas in Oahu. Wow what a pain to have to go out of your city to gas up just because you don't want somebody else to pump your gas. Well at least you have that choice. Before I had this bladdered gas tank Prius it didn't bother me that much have somebody else pumping my gas. Beautiful country where you live. We have been in that area many times in our lifetime.

    bisco is there a way to check the carbon canister???
     
    #8 93dawg, Oct 18, 2014
    Last edited: Oct 18, 2014
  9. 93dawg

    93dawg Junior Member

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    Ah ha I think all is well. I had 45 miles on the odometer and late yesterday I drove another 45 miles and got my MFD mileage average up from around 38mpg to 46.5 mpg. So I think the problem was all the real short trips I made around town here in Southern Oregon... Live and learn!

    Thanks to all who responded for your help and suggestions.

    Gas price is down to $2.99/gal here in Southern Oregon Whoopee!!!

    Jim
    ===
     
    #9 93dawg, Oct 19, 2014
    Last edited: Oct 19, 2014
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