How full is full?

I have had my new 2005 PRI for 2 weeks. The first 248 miles I average 61 mpg. The second week I went 201 miles on 2.65 gal. 75 MPG. I thought the tank was not full because the fuel gage would not read full. I find out this is normal if you put less than 3 gallon on fill up. I tried to top off the tank again after riding 2 miles and it took .24cents. I still can't beleive 75 mpg. The economy dash indicators read average 57.8mpg.
I am well satified and waiting for the next fill up. I am using BP (Amoco white high test 93 octane)

 

This is about my only complaint about the Prius - filling it with gas can be "problematic" at times. I've gotten used to about how much it should take at each fillup (the consumption display is pretty accurate - divide miles driven by calculated MPG and that's about how much I should take). Last week, I figured I'd need about 8 gallons to fill it, but the pump shut off at 5 gallons and I had to "pump and click" the other 3 gallons. I suppose it's a pump issue because there have been times that I was down to the flashing bar and pulled up to a pump. It clicked off after one gallon and kept clicking off. I finally ended the transaction and moved to another pump, where it pumped in okay. Bottom line, you really do need to "guestimate" how much it should take when you fill it, as the pump shutting off isn't always an accurate measurement.

Also, you really don't want to overfill the bladder. I did that once...and I'll never do it again. It doesn't "splash back" like it does on other cars...it takes the gas happily thru the "pump and click" phase, but when you pull the nozzle out, gas just SHOOTS out of the filler neck.

 

Recommended octane is good ol' 87. Higher octane may light the engine light on the dash, due to higher octane (oxygen sensor?).

Also if you decide to top off, do some searches here or google to see if it's worth the potential emissions damage as well as pocketbook.

I've read that the evaporative emissions filters need room to work in the tank. Squeezing in too much fuel defeats this important feature of a "partial-zero emissions vehicle".

I've read that the gas you think is going into your tank by topping off is actually going back to the underground tank via an overfull pipe on the pump. Just some things to think about.

Don't forget that temps have an effect on fill and range too. Cold = smaller tank, fewer miles per tank. Warm = bigger tank, more miles per tank.

 

Also, you really don't want to overfill the bladder. I did that once...and I'll never do it again. It doesn't "splash back" like it does on other cars...it takes the gas happily thru the "pump and click" phase, but when you pull the nozzle out, gas just SHOOTS out of the filler neck.


As someone who just did her first fill up on my Prius--I can attest to the truth of this with a huge sigh.

My display told me I'd driven 412 miles and I had an average of 50.3 mpg. I was down to 2 bars and I thought since this is a new car I didn't want to risk running out of gas on my commute where gas stations aren't always available. The pump clicked off at 7 some gallons but it had also clicked off before I had a full gallon in the tank and I'd just sort of bumped the nozzle when my hand got tired. So I kept pumping--and when it didn't shut off and I noticed there were 10.2 gallons on the pump, I kinda thought something was wrong. I pulled out the nozzle and whoosh--gasoline spurting out, etc.

With all the reading I've done here, you think I would have been smarter....so I hang my head in shame.

Lesson learned--do a little bit of quick math before filling and probably go down to one bar before fill up.

Barb in Lebanon PA (although I probably shouldn't admit where I am after the screw-up)

 

Weird. I've had my 2005 for almost two weeks now, about 330 miles on the car. When I hit half-tank, I decided to fill up, and had no problem fueling. The pump clicked off after 5 gallons exactly, which made sense vs the MPG on the computer.

But, I've only been managing about 39mpg so far, almost half-way into tank two. Now, my area of southern california is hillier than some, but I can't imagine that would make a 7+mpg difference. I believe that my MPG disparity is due to two things:

1) I simply cannot accelerate as slowly as would be effective for the Prius. I will be run over by a terrorist vehicle if I do. Once in a while with no one behind me I'll let the Prius crawl to speed, but I've seen too many giant grills getting way too close to my baby to be ginger with the gas.

2) MTBE: it's still in my gas!! I read somewhere utterly non-authoritative that "some hybrid owners have noticed up to a 10% difference in mileage between oxygenated and non-oxygenated fuel". Has anyone else heard this? Are there any additives that might counteract that effect?

 

I would love to not have the bladder. It is a hassel. I have learned that some gas stations with older or more heavily used filler nozzles are the most finicky with the Prius. For example, I was out of town and filled up at a Costco that was fairly new, therefore their gas pumps were fairly new. I had no trouble filling the tank fully and automatically with newer nozzles. However, back at my local Costco the nozzles rarely ever fill the tank fully. It is an older Costco filling station and as such I think the nozzles are worn out or not sensing things correctly in the neck of my tank.

I really wish I understood why the bladder gives "incorrect" fill up signals to the nozzles. Very annoying.

 

Oh, and Mike, your low mileage is do in part to how tight your Prius is right now. After a few thousand miles you will see your mileage climb. Hilly terrain doesn't help mileage, however the newness of your vehicle is the biggest enemy to fuel economy.

 

Jerome: I've been hoping that was the case, but every once in a while I'm seeing reports of new owners swinging 47+ on their first tank. It makes me jealous :mrgreen:

 

Just filled up my first tank yesterday. The gauge was flashing and I was 30km into it until i filled up. I put in just over 38 litres using the "pump and click" phase to top it off. I stopped at just the right time, though... I pulled out the nozzle and it blurped a tablespoon of gas out (fortunately, non got on the car)!

 

got 660KM. It showed 4.8L/100KM on the MFD on that first tank. The dealership filled my first tank so they didn't fill it much past initial click. It clicked around 32-33L so 4.8L/100KM seems accurate.

 

I thought I broke my fuel gauge on my last fillup...the trip computer was reflecting surprisingly low mileage (40.1), yet I had 120 miles on the tank and it was still on the full mark. I was thinking of heading in to the dealer, but on the way to work this morning, it dropped off the F mark. Still can't understand why I could go so far before it moved off the full mark, yet would show such low mileage (usually shows no lower than 48 mpg on the computer).

 

I am not sure if anyone has determined this before, but I am curious about the number of gallons represented by each bar on the fuel gauge.

On a recent trip from KC to Stillwater I started keeping track of the miles driven on each bar and the overall tank MPG (as reported by MFD) as each bar disappears. I just refilled from that trip, so here are the results of that one tank.

The first bar disappears after about 2.6 gallons. The 2-5 bars each disappear after about 0.5 gallons. Bars 6-8 each disappear after about 1 gallon. The 9th bar and the flashing of the final bar combined happen after about 2 gallons, with the majority of that covered by the 9th bar.

I filled up with just over 9.62 gallons (without topping off), and after going home and doing the calculaitions I determined I had used about 9.62 gallons.

This data is only based on one tank. I will keep tracking this to accumulate more data, but since I am not commuting to work as often this summer, and each tank gets over 450 miles, it may take a while to get the data from a good number of tanks.

I will keep everyone posted on this. I am also intersted in hearing if anyone else has already determined all this.
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'05 Superwhite Prius
Stillwater, OK