Low Fuel Warning

We will fill the tank and subtract how much went in from 11.9 gallons. That is how we always did it in previous car. Will the bladder screw this method up?

 

Yes.

 

Then how does anyone really know what mileage they are getting? My guess would be the bladder would screw up the mpg on the consumption screen also.

 

Correct! People who calculate MPGs manually from gas station pump readings *don't* really know, except as a long-term average over many tanks. People who read the MPGs on the MFD really know to within one or two percent.

 

What is the MFD vs the MPG? We squeezed in 11.13 gal at the pump. We had 414 miles on the consumption screen. Hubby believes the dealer quit pumping when the hose first clicked (it first clicked for us at approximately 9 gal). If the light started blinking at 399.8, can I assume I will get at least 14 miles before runnining out of gas??? Or, from some of the posts, the weather plays a factor also???? Hummmm. Very disappointing.... Kind of takes away the "brag factor" when comparing mpg with other vehicles - at least with the 08 models.

 

Interesting discussion.

When I fill up I write on my receipt miles for last fill up and total miles on car and then I record the fill up in a spreadsheet that I've been using to track mileage of any car I've had. I record the mileage of the fill-up and total, along with price and date (and station name/location).

My averages vary as Delaware forces ethanol on all drivers in the Summer -- and it does not promote better gas mileage. So, on ethanol I tend to average around 42mpg. Without the ethanol, I'm averaging 62mpg.

I actually don't even use the on-board mileage system, though I watch it on long trips.

 

The safest thing to do is fill-up when there are still two pips still showing. That is what I do with the pump set on the slowest fill and I stop filling at the first time it clicks off.

The comparison between the mfd and my actual mileage can be all over the place. I don't know how some owners get only a one or two percent difference. I will try to attach a pdf copy of my spreadsheet and you can see what I mean about the difference.

 

I do not think the 07 Prius has the bladder in the gas tank the 08 does.... I think that is the issue, the bladder is causing some problems. :Cry: Why me...... I do love my little "Gumby" no matter what. I will also copy your spread sheet and see what results I get. Thanks!

 

My spreadsheet is pretty basic, Really just a place to enter the info. Don't worry about the column on the far right side. It counts down miles and when it goes negative for the year the insurance goes up. If State Farm asks, I, being the honest person that I am, will have to tell them the truth.

And yes the 07 has a bladder in the tank.

 

What is MFD stand for? How do you figure it vs MPG?

 

Multi-function display. The TV screen in the middle of the dash. I reset the consumption screen when I fill up and it stays that way till the next time I fill up. Then I also figure the mileage the old fashioned way by dividing miles driven by gallons. The two figures are sometimes fairly close, but many times they aren't.

 

By the way, Gumby, it is not a good idea to keep filling the tank after the first click-off of the nozzle. Over-filling into the filler neck can damage certain pollution devices such as the charcoal canister.

Once in a while you might encounter a pump that has a mind of its own and clicks off as soon as you start filling and keeps clicking off every time you try to re-start it. That has happened to me once in a year and a half. At a time like that you have to either try a different pump or become a little creative with filling.

What I did was barely insert the nozzle in the opening and make sure that it could vent. Then I calculated about what I thought the tank would take based on the miles that I had traveled and the mpg the screen showed. Then I filled very slowly till I had in what I had calculated and stopped.

Hope this helps.

 

Hi
This is Ronaldo. Once in a while you might encounter a pump that has a mind of its own and clicks off as soon as you start filling and keeps clicking off every time you try to re-start it. The safest thing to do is fill-up when there are still two pips still showing. This way it warns when the fuel is low.
=========================================================

Ronaldo

Pennsylvania Drug Treatment

 

Okie,

Sounds like good advice for newbies. Within the context of that advice, I'd like to add that, like many things about the Prius, one needs to get familiar with the quirks of the fuel system simply by developing some history. Get familiar with the car!

For eight months I passively filled the tank at one pip, and if I was lucky, I'd get seven gallons into it, stopping at the first click. By then I knew that the tank held more than that, so I experimented. Instead of filling slowly, I pumped the first five gallons at full speed, then pumped the remainder slowly. For the first time the tank took ten gallons. (As well as every tankful since then, using the same technique.)

However, there are a few things I am beginning to suspect that run counter to the conventional wisdom:

1) That the "first click" mark is much too variable to be a good indicator of a full (or only nearly full) tank.

2) That accepting the first click as gospel is "fine" and "safe" but can be abandoned once one becomes familiar with the car.

3) That the Prius fuel system is more robust than most owners believe.

4) That filling problems commonly attributed to a particular pump are more likely to be a fuel system issue.

5) That filling the tank slowly may not be the answer to all fueling problems. I think it is better, as you pointed out, to get creative.

Please bear in mind that these are not suggestions. They are, at this point, merely my personal suspicions.

 

MFD = Multi Function Display, the big screen in the middle of the dash. The "Consumption" screen shows moment-to-moment MPGs and per-tank MPGs. The car calculates MPGs by measuring the fuel flow into the engine (it counts actuations of the fuel injectors). The MPGs shown there are accurate to within 1 or 2 percent.

You should not assume anything about how far you can drive once the light starts blinking. The MPGs you get change constantly depending on driving conditions, and the fuel tank bladder makes it impossible to know how much fuel is still *available* inside the tank. The blinking light really means "buy gas right now".

 

That really is a bummer - so much for technology!

 

When Toyota figures out how to predict what the driver will be doing and what driving conditions will be for the next hour, we'll get back to you :_>

 

Sorry, I'm a newbie.... not expecting a crystal ball reading... reading the posts puts lots of doubts in my mind. Just curious on how to get an average with the differing input. It is interesting how pulling out or even the slightest of grades drops the mileage. My former car always averaged 20/30 with mixed driving since we live near and use an interstate on a regular basis but for short distances.

By the way, on my first fill up I so far have 152 miles and all bars are still up. We came close to topping off - have since been advised that is not wise. My first tank full (dealer fillup) I got 414, I'll see what we get with this one.

Gumbie

 

Answer - twice we have run out with our 2009 Prius and have gotten to the gas station on the battery. In each case, we got about 30 to 40 miles on the last bar and then when the alarm sounded and the last bar started blinking, we got less than 3 miles, maybe even only 2 miles. The first time we thought it was because the gas tank (bladder) had collapsed since we were only able to put 5 gallons in the tank (we put another 6 gallons in later that day). But the last time we ran out, we got about 11 gallons in the tank with no problem. so the gas tank was not crunched up.

So if you have a new Prius and you are not sure how it behaves. I would fill up as soon as you hit the first bar, don't wait for the alarm and the blinking bar (unless you carry an extra gallon of gas in your car).

 

Someone please explain to me what the joy is in running the car out of gas. You've just gone farther than most any other car sold here in the U.S. on the approximately 11 gallons of gas that a Prius will hold. If going 400+ miles on ten gallons is not enough for you then I really can't figure out what is. You really won't get a medal to pin to your chest when you wind up coasting into the gas station on the battery with the TRIANGLE of DEATH about to appear when the traction battery gives up the ghost. In fact you do that often enough and you'll void the traction battery warantee or it will cost you a tow to the dealership to have them recharge the traction battery and a couple of bucks for the charge. Fill the bloody thing up when it is down at one pip or if you can't bring yourself to do that when the last pip is flashing.