First Tank Question

Many here call it the guess gauge.

It's not very accurate.

 

Depending on the weather and other conditions, the first pip in my car disappears between 80 and 125 miles (normally 100). The rest go down relatively quickly.

Don't forget you have a bladder in the fuel tank. When new or cold, the bladder is stiff and won't let you put in a lot. For example, you're on the last pip and put in 9 gallons. It doesn't mean you have 2.9 gallons still in the tank (and figure another 100 miles of travel on the last pip), but that you could only put in 9 gallons.

 

<div class='quotetop'>QUOTE(Highly ImPriused @ Apr 6 2007, 11:47 AM) [snapback]418894[/snapback]</div>

Hi Highly Impriused,
I had an occurance where the second tank only gave us 344 miles and averaged around 43.? on the screen.
Have tried a different gas station and have gotten much better mpg around 52 mpg. So we no longer visit a certain station, just to save 3 cents per.
I think a lot of it has to do with the gas station fuel quality, and or pump nozzel as far as getting a "full" tank.
A funny thing our salesman called us to sign a paper they forgot to have us sign at delivery so I told him I wanted a full tank of petrol, he agreed went there got filled up signed papers and so far we are getting 55 mpg and 450 miles with a couple of pips in fuel gauge. So who knows?

May have water in gas station tanks? but also it has cooled off here again and mileage dropped, Will look into getting an engine block heater installed. Hope we all can get more MPG's
have a good day

 

The dealer might shortchange you? How dare you!

The prius fuel "tank" is actually a flexible bladder with some idiosyncracies, one of which is less flexibility in cooler weather. This limits the amount of fuel it takes. It probably was as full as the dealer could get it. The first bar lasting for 60 miles isn't unusual in cooler weather, and in any temperature the next bars disappear faster. Like conventional guess ... er, gas gauges, it's a non-linear relationship between the gauge and the fuel level, though this relationship is harder to figure out.

Refueling at 3 bars is certainly safe, but perhaps a little overcautious. I and many others let it get down to one flashing bar, though once it starts flashing I refuel at the next opportunity. I do not want to run out.

Even then, about the most I can get into the bladder on a warm day is about 10 gallons.

I suggest you search here using terms like "bladder," "gas gauge," etc. There are perhaps dozens of posts that describe the fuel system.

 

<div class='quotetop'>QUOTE(Highly ImPriused @ Apr 6 2007, 10:20 AM) [snapback]418924[/snapback]</div>

Ahhh, you're assuming the dealer was able to put in 11 gallons. They probably filled it until it stopped.

 

I am having the exact same results on my first tank from the dealer. When I brought it home, I saw 45+ on the screen, now it barely stays above 40. A lot I found is the weather, the day I brought it home it was in the 60's, it is unusually cold here the past few days, hasnt gone much above 30 during the day and I think that is affecting it, another factor is I have a lot of hills around me and the drives I have been doing are on those roads, so it eats up fuel. Today I drove all the way to where I work and I saw a difference between the driving around the towns and the roads near my house was quite different, so I think next week when I go back to work I will know better what the numbers will be. I will be taking a different route this month than I normally do as it is more direct, but more hills, and that may make a difference, I may just go the long way and see how it comes out will less hills.

 

<div class='quotetop'>QUOTE(Highly ImPriused @ Apr 6 2007, 10:31 AM) [snapback]418930[/snapback]</div>

Yes. I usually get from 135 (winter) to 185 (summer) miles on the first bar. If you got only 60, depending on your driving, you could have been two to two and a half gallons short of a full tank.

 

<div class='quotetop'>QUOTE(IsrAmeriPrius @ Apr 6 2007, 10:00 PM) [snapback]419140[/snapback]</div>

I've never been to either locale, but I highly doubt Fairport, NY has a climate anywhere near as ideal as southern CA. From what I've read, that has a major impact on the bladder's actual capacity. Full is full, whatever the bladder dictates full to be at the time.

From what I've read, it sounds like most folks are seeing/estimating 8-10 gallons of accessible fuel, depending on climate, season, and a host of other factors.

I'm only on my third tank, but already the data is kind of interesting. Perhaps it will calm your concerns a bit.

Tank #1: First bar dropped somewhere around 60 miles. Refueled after 358 miles. Two bars left on gauge. MFD indicated 48.4 MPG for the tank, so I burned 7.397 gallons of fuel. Fuel pump shut off after 6.779 gallons.

Tank #2: First bar dropped after about 40 miles. Refueled after 248 miles. Three bars left on gauge, but didn't want to push my luck with a drive of unknown distance slated for the next day. MFD indicated 51.5 MPG for the tank, or 4.816 gallons burned. Fuel pump shut off after 6.076 gallons.

Tank #3: In progress. A little over 75 miles so far and the gauge has yet to drop a bar. MFD is around 50-51 MPG so far.

So, by all indications tank #3 began with about 5/8 of a gallon more fuel than did tank #1, whereas tank #2 began with about 5/8 of a gallon less than tank #1.

I'm sure on occasion I'll stretch it further, but for now I'm being cautious while I get a feel for how the bladder in my Prius behaves. (Almost said "my bladder," but thought better of it.)

You'll probably just have to give it some time. There are many variables at work here, so it's silly to leap to conclusions on so little information.

I definitely recommend tracking your fuel economy in a spreadsheet. I write my odometer mileage on my fuel receipt, then use the info to determine various stats such as trip mileage, trip economy, and YTD totals/averages.

- Justifyd

 

Hi guys, I just posted a very similar query on another forum here.
Here's my situation: Presumably full tank of gas from the dealer-> 2 bars remaining on fuel gauge today->filled up for the first time 8.6 gallons at 311 miles. Average mpg per the info screen never above 40 mpg.

Not sure how or even whether I should extrapolate anything at all from the above data.

Was also wondering if the touring model I have gives less mpg than the non-touring model...

 

I have to agree with OP...I am finding the same thing happening on my first tank as well. My MPG average according to the MFD is 52.5 and yet with three bars left I have only traveled 300 miles since delivery of the vehicle...nowhere near the MFD average even if I can milk another 100 miles before refill. Here is hoping it was just an underfill at the dealer.

 

<div class='quotetop'>QUOTE(Highly ImPriused @ Apr 10 2007, 08:27 AM) [snapback]420849[/snapback]</div>

That is a perfectly normal pattern. After the first bar drops, the next four disappear at intervals of 30 to 35 miles. Then it is about 40 to 50 miles for each of the next four to drop. The last bar starts to blink about 30 to 50 miles after the second bar is gone.

On my present tank the bars dropped at approximately 160, 190, 208, 250, 280, 335, 380 and 408. I am now at three bars with about 420 miles on the tank. I expect to fill it up at around the 500 miles mark.

The MFD shows 54.5 MPG for this tank.

 

I also am from new york about 25 miles from the city. I took delivery of the car in the beginning of feb and the first three tanks only lasted me about 360 miles at the most. What I found was that the blatter does not hold 11.9 gallons.. more like 8-10 gallons of usable fuel.

I noticed that on a 15 degree day, I could at most put in 8 gallons with a blinking bar. Stuck me at first as a problem but then after careful research I found that the blatter will contract 1 to 2 gallons depending on the ambient temp. Because of this less fuel is being carried, hence the first bar going down quicker. I tend to average between 70-85 miles before it drops on really cold days

During that 60 degree spell we had in southern ny I was actually getting around 100-120 miles before the first one would drop, and that tank took 9.9 gallons to fill at the blinking bar. Something to think about.

Also I found that at 2500 miles (I drive alot) there was some sort of break in because the MDF rarely sees lower then 47 mpg (last two tanks 50.5mpg) Something you might want to look forward too.

Then there is the driving habits.. those change with time .. trust me..

Good luck with the new car.. hope everything goes well.. you will love it

 

<div class='quotetop'>QUOTE(Highly ImPriused @ Apr 10 2007, 07:00 PM) [snapback]421272[/snapback]</div>

After looking at my notes, which I keep in the car, I need to make a correction of the numbers I reported above. It should read 160, 190, 208, 260, 315, 366 and 408. I am still at three bars with 430 some miles on this tank. I'll keep you updated.