My prius is a gas guzzler?

I have yet to own any car where the gas gauge was sufficiently linear to accurately estimate fuel usage, without the knowledge gained from actually refilling it.

Your Prius will be even worse. The tank bladder introduces considerable variability, and will require more refills before you get a feel for the pattern.

-- Dean, not yet a Prius owner.

 

You could have driven 275 miles in a week and a half. The time doesn't tell us anything. How many miles have you driven and was the tank definitely full when you got it?

 

I've been driving an '08 for over a year now. The gauge is not the best judge of mileage. I've had a couple of times I thought things were way off, but when I filled up and calculated, I always run very close to what the on-board calculator shows. I'm at 52.5 now that it's warmed up. I was down in the mid 40's during the cold weather. Just drove to Florida and back and got 53 for the trip. Relax and enjoy the ride.

 

How do you know it was full? If you didn't see the dealership top it off, you can't be sure. It's not unheard of for newly purchased cars to be driven off the lot with less than a full tank. The gauge will indicate full even if it's not quite there; the first pip on the fuel gauge could take anywhere from 50 to 200 miles to disappear.

Meanwhile, just be patient and trust the display. Some of us have tracked the difference between displayed and actual fuel economy over many tanks, and the difference is within 2-3%.

 

Fill up the tank and you'll have a measure of the amount of fuel burned. Then compare the pump calculated value to the display. But save the data somewhere.

There is considerable variability in fill-up values for partial tanks. But I was able to use this data to tweak and tune different aspects of my 2003 Prius. Having a mileage record is the first step to figuring out how well the car is performing as well as learning how to optimize performance. This first set were recorded in a spreadsheet and plotted to give:

The dealer I bought the car from had put in the extra oil. Two months after buying the car, the temperature dropped.

One caution, unexpected running out of gas can happen when the gas gauge (often called 'guess gauge') gets near the bottom. I've gone as little as 25 miles and as far as 130 miles with the bottom pip flashing. The average has been closer to 65-75 miles. In my case, running out of gas has been planned so I carried a 1 gal. spare can.

Running out of gas lets the car continue on battery at a slow speed but I've only used the limited battery capacity to find a safe place to park and add my spare gas. There have been reports of folks going a mile but this is really pushing it. Repeated attempts to start the engine after running out of gas can set a code that has to be cleared by towing the car to a dealer ... not a good thing.

GOOD LUCK!
Bob Wilson

 

Unless you KNOW you put X gallons in the tank, you don't know how full it is.

 

I would unload that gas guzzler as fast as you can. I'll give you 10K for it, which isn't bad considering that your Prius is defective.

Tom

 

I am in almost exactly the same situation right now (just bought an 09, first tank is going much faster than expected, etc.) but I am comforting myself with the advice given here. All of it seems sensible. I think the last post about how far you might be able to drive on the last bar is really important. If I could go 80 miles on the last bar, all my concerns are gone; if only 20, different story, but I'll have no idea until I see how much goes in the tank and even then, who knows if the dealer topped off as I would? That first bar went fast!

I'll report back, but this is a helpful thread.

 

Don't chance it on the last pip. If you are down to one pip, you should have already refueled. The built-in inaccuracies of the gas gauge mean you should never push it at the bottom of the tank.

Rest assured that the mileage shown on the MFD is very accurate. Depending on tires, most posters find it is somewhere between dead on and 2% optimistic.

Tom

 

I bought a used 2006 and the tank said it was full but I put 5.06 gallons in it and have driven 420 miles and it is on the 1/2 make. the fool gauge is not that good of a indicator of what it says and what it has. I would love to get 420 miles on the second 1/2 but I know it will never happen.

 

Five gallons fill at half full is pretty normal.

Tom

 

No, it said it was full and I still put 5 gallons in it.

 

You know, my first tank dropped pretty quick. Dropped to 3 bars with about 270 miles. Filling it up took about 7.5 gallons. The second tank got close to 400 miles before it hit three bars.

Don't freak out on your first tank. You won't know what your fuel economy really is until you run a few tanks. I use mymilemarker.com to track my usage.

 

Gotcha. I misread your post.

Tom

 

Tom, I see you have a 2006 also, could you look at this post and see if yours works like mine.
Thanks

http://priuschat.com/forums/audio-electronics/60250-useful-voice-commands-bluetooth-info-2009-a.html

 

You people are all crazy. I have a 2007 and routinely have half a tank at 200 miles, sometimes sooner. I rarely can hit 400 miles in a tank.

This is all normal. Plus, first tank is likely messed up due to new vehicle - more playing - unusual stopping, driving and generally not knowing exactly how full it was.

whole thread is silly from the OP on down.

 

Did anyone remember to tell the OP that he doesn't "really" have an 11.9ga tank?