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Yet anothe fuel gauge issue

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DrDoug, Feb 28, 2014.

  1. DrDoug

    DrDoug Junior Member

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    I've searched the forums and don't see my exact problem shown. I've had my 2008 with 130k miles on it for a week and a half. I had previously done a lot of research here and learned about the bladder issues, how to fill the tank, try to fill when warm, and allow the tank to "breathe" before filling. My tank shows full after refill and clicking off. I am usually down 1 bar at 60, but by 220 miles or so I'm down to 2. Each time I fill up (twice so far after initial filling), I've only been able to put just over 4 gallons in. My only concern is I don't know if the tank is full and showing empty when it's really not, or if the empty reading is closer to it. I have no fault codes set. The temperature I've filled at has been around 40-45 degrees, so not warm, but not terribly cold.

    I've never dared take the level down further than that, but we are planning a trip from SLC to Dallas and there are times when I will need to drive more than 200 miles without refilling.

    Thoughts?
     
  2. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    On a full tank you should easily traverse 400 miles. If it were me, I would try to push out 400 miles on my current tank ((providing your averaging at least 40mpg)no matter what the gage says). It will be scary yes but, there is no reason you can't do it. 4 gallons is pitiful, you should be able to put at least 9 gallons in it regularly. The bladder doesn't shrink that much.
     
  3. DrDoug

    DrDoug Junior Member

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    That's what I really want to do, but it is scary reading about the trouble with running out of fuel. My average based upon filling the tank to where I have been, closely following the MFD reports of right at 50 MPG, so I know I could go a long distance if my tank were truly full. I just don't know if it is... I should mention that I've performed the recalibration of the fuel meter, successfully I believe, at least the indicated results were seen though no change in the reading. It wasn't made clear in that post if there's an ideal time to do it. To me, it made sense to do it on the mid-to lower portion of the tank, but again, I saw no change in the reading. Frustrating.
     
  4. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Let me tell you that the best way I've (this is just me) found to "calibrate" the guage. I run the tank down as low as I can comfortably get it (regardless of what the gauge said). Then fill it up til it turns off and add another dollar after that. That is the usnavystgc way of calibrating the Gen II Prius gas guage. I did this in the winter and I was able to put 10.3 gallons in her. :)
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    "Each time I fill up (twice so far after initial filling), I've only been able to put just over 4 gallons in."
    How many bars appear on the fuel gauge, at the time that you decide to refuel?
     
  6. DrDoug

    DrDoug Junior Member

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    2 bars are showing when I've decided to refill (just barely from 3 to 2).
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Well, for fun you might buy a small gasoline container, fill it, and bring it along as you explore how low you can go with the fuel gauge. You need to be prepared to disconnect the 12V battery for a few minutes, then reconnect it, after adding fuel from the container. Otherwise, after an out of fuel situation, the engine ECU may not recognize if you only add 3 gallons or less, and refuse to allow the engine to start in an effort to save the traction battery from discharge.
     
  8. DrDoug

    DrDoug Junior Member

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    That's a good idea Patrick. I'll carry around 3 gallons when I'm getting low and see if I can push to at least 400 miles.
     
  9. bisco

    bisco cookie crumbler

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    make sure it has a spout that will fit in the filler tube.
     
  10. JimN

    JimN Let the games begin!

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    You lost me. How far did you go & how many gallons did you pump? Use the displayed average fuel economy as a guide. Reset it every fueling & keep track of the historical data in a spreadsheet.
     
  11. DrDoug

    DrDoug Junior Member

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    I've been getting just over 200 miles when the gauge is down to 2 or 3 bars. Each time I have put in almost exactly 4 gallons. I'm using Gas Cubby to track all fuel usage. I did notice the last time when I filled up that it took more and where my fuel economy gauge was within a percent or two of calculated economy, this time it was way off. I expect that it was because the weather has warmed and the bladder expanded a bit.
     
  12. RobertK

    RobertK Member

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    Try calibrating the inclination sensor for the fuel gauge. Search PriusChat and you'll find the procedure. It might not fix your problem, but it is free and easy. The level in the tank is supposed to be between 1/4 and 3/4 full, which can be obtained by filling the car and driving 200 miles before performing the procedure.
     
  13. bisco

    bisco cookie crumbler

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    make sure your on a level surface.