Gas tank display still showing full

i usually hit around 110 miles before my first bar goes down, so maybe give it a little more time. if you hit 150-200, then i'd be worried.

 

If the tank is really full you can use about 3 gallons before the gauge moves. If you are getting 55 MPG, you can go 165 miles before the first pip goes away!

 

That's funny because those states which do not allow you to pump your own gas often do it for just this sort of reason -- to prevent you from topping off, which has been demonstrated time and time again to be bad for the environment. That kid needs to be reported to his boss and given some re-training.

 

The typical "topping off damage" that Tony referred to rather quickly results in a warning light on the dash. No warning light means you can relax and not worry about the charcoal canister this time.

Some people top off frequently and never have a problem. On the other hand it is entirely possible that the first time you top off you could accidentally flood the canister. Since it is difficult to determine if you are going to flood the canister until you've already done so, it is safest to simply avoid topping off. If someone tops off your tank and you don't get a warning light on the dash within 2 or 3 trips in the car, you're probably in the clear.

 

If someone tries to top you off again, leaping out and shouting "GET THE F!!CK AWAY FROM MY CAR!!" should be effective :_>

 

My first pip usually goes around 125-175. I hate having people pump my gas.

 

On my wife's first time putting gas in the prius that I've had for a little over 2 months, she put in 91 when I always put in 87 and the pump did not shut off. She said it seemed like 2 gallons shot back out of the car. She was a little horrified that she might have damaged the car after I told her I don't use 91. I went 220 miles before my first pip went away, a little over 400 miles when it showed a half tank of gas, and finally almost 600 miles on that tank of 91 octane. I have never gone over 430 on a tank of 87. I drive 100 miles round trip daily to work.

I have put 87 back in and my mileage has decreased back to normal range for my driving conditions and when that is all gone, I'm going back to 91 to see if I can duplicate those previous results.

 

The MPGs did not change, the range did: she simply got more fuel into the tank than usual and no doubt also saturated the vapor canister with fuel. You will not reproduce the increased range unless you also reproduce the fuel spew. And you don't want to do that because (1) it's pollution, and (2) it can damage the fuel tank bladder, which is expensive to fix.

Aside from all that, 91 octane in a Prius is a waste of money because it doesn't contain any more energy per gallon, and the engine adjusts its timing to compensate.