Driving Past The Add More Fuel Beep

[Frayadjacent]

Tempting fate is not worth enough to risk any expensive components in my car to see how far I can get before it tells me I need to put gas in it.

With the wide variation in fill volume due to the fuel bladder, it's even more risky.

I usually stop to fill when I get down to about 2 bars on the fuel gauge, usually around 400-450 miles.

[DaveinOlyWA]

i dont think it is, but i am hardly an expert of fuel pump dynamics (in fact i know nothing at all about them) but the blinking bar starts at about 12% of tank volume. that is over 1½ gallons. seems that would be plenty to keep something sitting at the bottom of the tank submerged

[wfolta]

Originally Posted by DaveinOlyWA

i dont think it is, but i am hardly an expert of fuel pump dynamics (in fact i know nothing at all about them) but the blinking bar starts at about 12% of tank volume. that is over 1½ gallons. seems that would be plenty to keep something sitting at the bottom of the tank submerged

My guess would be that tank sloshing from car movement would tend to stir things up a bit, and the less fuel in the tank, the more that movement stirs up stuff at the bottom. I'll have to get a glass of water and see if that's really they way it works or not.

(I assume that the tank does not drain from the bottom, so there'll always be fuel below the level of the intake.)

[DaveinOlyWA]

Originally Posted by wfolta

My guess would be that tank sloshing from car movement would tend to stir things up a bit, and the less fuel in the tank, the more that movement stirs up stuff at the bottom. I'll have to get a glass of water and see if that's really they way it works or not.

(I assume that the tank does not drain from the bottom, so there'll always be fuel below the level of the intake.)

actually i believe the fuel pump is an inline type and is situated slightly below the tank in a small funnel-like depression near the front of the tank which is also the way the tank is "tilted". so the likelihood of it being dry when the tank is low is not very high. the bottom of the tank is not flat

**edit**
i hit my blinking bar on Monday and will most likely be getting gas sometime today. (its my day off and i like the gas lines at Costco MUCH more on a thursday morning than a saturday afternoon!!)

i have probably waited until the blinking bar 80%+ times in all the fillups on the 3 Pri's i have owned. now granted, none of the 3 are old enough to have been filled enough times to make any determination on long term effects of practicing this habit. (thank you Pri for allowing fillups as much as 3 weeks apart!!)

now, not exactly sure how much i have in the tank, my DTE was around 42 miles when the blinker went off. last time i did a big fill, i went 60+ miles past the ZERO mark on DTE. probably wont be doing that today since i dont have enough errands today to drive that far. all driving today is basically in town for expected things to do today...will post results as always

[morpheusx]

When the PIP starts to blink there seems to be approximately 1 gallon of gas left in the tank. A variable that many do not consider is that it may depend on your current consumption rate on whether or not you can go 20 miles or 50 miles. You should also consider whether or not you have any cold starts or short trips. The only way I would trust it is if you were to press reset on the consumption screen right as you get the warning. Theoretically based on others testimonials you should run out of gas just as your MPG and miles travel are the same number.

[Son of Gloin]

An interesting thread all the way through.

( So, the last "pip" goes out and then the thing starts "beeping" at a certain point? Or does the last "pip" start "blinking" and "beeping" at the same time? )

As for me, I rarely let the "guess gauge" get below TWO pips ... especially on long, highway trips, when I can never be certain of how far it might be to the next gas station. The very last thing I want to do is run any risk whatsoever of running out of gas in a Prius.

And, as a side note to this thread: while I've kept a record of the display's MPG at every fill-up, I always use miles driven / gallons pumped to figure Mithril's "official" mileage. When the display itself starts paying for the gas, I'll take it's word for it ....

[boppo]

Originally Posted by morpheusx

When the PIP starts to blink there seems to be approximately 1 gallon of gas left in the tank. A variable that many do not consider is that it may depend on your current consumption rate on whether or not you can go 20 miles or 50 miles. You should also consider whether or not you have any cold starts or short trips. The only way I would trust it is if you were to press reset on the consumption screen right as you get the warning. Theoretically based on others testimonials you should run out of gas just as your MPG and miles travel are the same number.

I drove my 2006 for a while and the last pip was not yet blinking and I put 11.625 gals so there can't be a gal left when it starts blinking. At least not in mine.

[CharlesJ]

Originally Posted by morpheusx

When the PIP starts to blink there seems to be approximately 1 gallon of gas left in the tank. A variable that many do not consider is that it may depend on your current consumption rate on whether or not you can go 20 miles or 50 miles. You should also consider whether or not you have any cold starts or short trips. The only way I would trust it is if you were to press reset on the consumption screen right as you get the warning. Theoretically based on others testimonials you should run out of gas just as your MPG and miles travel are the same number.

According to the manual it is 3 gal remaining, approx. when it starts blinking.

[CharlesJ]

Originally Posted by boppo

I drove my 2006 for a while and the last pip was not yet blinking and I put 11.625 gals so there can't be a gal left when it starts blinking. At least not in mine.

On my first tank after purchasing it used, I went 58 miles after it started blinking, pumped 10.2 gal and had 46.2mpg. I also think that on that last start up before filling, besides blinking it states get fuel. Another fill up 41 miles past blinking, added 10.55 gal. On the last fill went 38 beyond with 10.6 gal fill and no extra message to fill up. I think it is good to know what one's car is doing as it seems to vary so much?

[CharlesJ]

Originally Posted by KAR IDEA

Sooooooo, I grew tired of playing the "Add Fuel" game after driving the car for nearly two years, and adding fuel as soon as the car told me to.

One day 8 tanks ago, I decided to drive 20 miles further and the car took 10.1 gallons. Then 7 tanks ago I drove 30 miles further and the car took 10.6 gallons. Then 6 tanks ago I pushed it to 40 and the car took 10.9 gallons. Then 5 tanks ago I drove 50 miles further and the car took 10.8 gallons. I kept it at 40 to 50 miles beyond the add fuel warning for the next 3 tanks, and the car took between 10 and 11 gallons each time.

I just filled it today and pushed this last tank/bladder to 60 miles further. The car took 11.2 gallons.

If this is information is useful to you, excellent! If it's not, that's fine too. My little experiment in a nutshell, has proven to me anyway, that I am safe driving at maximum, 50 to 60 miles past my add fuel warning...something to keep in mind when on a lonely road with no gas stations in sight. : )

I have had similar experiences on my experimentations so far after 4 fill ups. 1st one was after 58 miles past and a 'fill now' as well with 10.2 gal and 10.6 gal on the last fill with 38 miles past.