Misleading fuel guage near empty

I'm upset because my digital readout won't go into negative numbers on remaining miles left to empty. Staying at 0 miles seems like an oversight in programming to me.

 

Haha, well said.

 

I just reset "Trip B" when the MTE gets to "0".

 

You forgot to say "Now get off my lawn."

 

I just look at current tank MPG and multiply by 10, then round down to the nearest 100. Been fine so far, most i got in once was 42 litres.

 

These "how low can you go" fuel threads keep surfacing every 45 days. I never go below 1/2 - 1/4 tank; 'nuf said!

How come we never see a thread about how many miles can you drive beyond the required oil change interval?

 

I change oil once a year on my Tacoma regardless of mileage. The longest distance between oil change is 18,000 miles. Is that far enough for you for a car requires oil change every 5,000 miles?

Many reported that it takes 9.5 gal when low fuel starts flashing and 10 gal when DTE reaches 0. This is on the first click. Bob reported that after DTE reaches 0, there's still about 2 gal in the tank. Many people also reported that they have pumped 2 more gal after the first click to fill up to the neck. I have always pumped 1.5 after the first click. I can always hear the fuel in the tank after each filling. This adds up to about 13.5 gal of total fuel. On my last fill, I pumped almost 12.5 gal of gas. http://priuschat.com/forums/gen-iii...-vehicle-has-bigger-thank-than-you-think.html
From brim to bone dry at 55mpg, you can drive just under 750 miles a tank. First person to do this earns my respect.

 

There have been threads here about people running a Prius around 20k miles without an oil change.

 

because you don't have to get an oil change that frequently.

when i first got my prius i was hoping to only have to fill up once a month, but it turns out that i have to fill up almost as much as my previous car that only got 20mpg because the prius tank is so much smaller. if i could squeeze out another 100miles before filling up it would get me that much closer to that once a month fill up. it's a convenience thing for me.

 

cpr: Nice, but would you do that in your Prius?

 

I don't understand why american cars need new oil every 5k miles, or some people say 3k. Over here oil is once every 12 months or once every 20k. I think it's annoying that the prius asks every 10k, it just seems unnecessary.

 

No brine flies or shrimp served there. Only the good stuff. Might I recommend the mango fish tacos?

Man, I did sound rather old and crotchety there didn't I? lol

I've gone well over 15k at one point. I just didn't think about it until the oil started to turn an ugly color. When I checked it I found it needed about a quart to fill it back up so I figured a full oil change was the wiser course of action.

 

+1: Flan, I sometimes wonder if consumers have been duped by oil companies and service centers. If oil (esp synthetic) is clean going in and the filter is a good quality, why does it need to be changed so often? If there's that much debris in there, why is the engine still running? I agree, let's see mfg get these intervals extended to at least once a year and some other mileage than 3k, 5k, or 10K. This has all the makings of a new realty TV show, "Consumer Fleecing"

 

I honestly think it's a kickback/scam. "we'll provide free oil for each car you sell, so long as you keep saying it needs to be changed every 3k"....

 

I think it has to do with the poor quality of engines and emissions systems from back in the day. A poorly running vehicle may contaminate the oil with fuel and sooty deposits which may break down the oil and/or reduce its lubricating qualities. I've observed this in my early days of racing where I tried tuning fuel injected engines myself and end up with rich mixtures or bad head porting. Within a couple thousands miles of driving/racing you could smell and feel the fuel in the oil and observe the color change. In a clean running modern (non-modified) car the oil lasts much longer before you notice the oil changing color or viscosity.

So in a nutshell, I think we are still running on the old school ideology of "change your oil at 3k" instead of what each car truly requires.

 

Good Question!!! We were told at the "Dealer" that when the Prius reaches Zero that you better be sitting at a gas station. He said that "All toyotas are like that!". I like cagauss' question about that. Can you go another 50 to 60 miles with no problem. I have always heard that you shouldn't pump in extra fuel or you can ruin the tank sending unit. If you are at $10.12 does that mean you shouldn't go to $11.00 or was he out of gas and after the pump cut off could he have put another gallon in the car? These are nuances that I wonder about on the Prius. I have a Honda Odyssey and I can usually put about 2 more gallons in the tank after the pump cuts off (21 gallon tank). The BMW when it cuts off you might get 10 cents more before it spills out after cut off. This is what makes this site so good.

Thanks guys
Craig

 

I'll get the free oil change at 10k miles for now. After that, It's back to once a year regardless of miles. I do worry about http://priuschat.com/forums/prius-p...ic-vehicle-use-high-fuel-dilution-in-oil.html I don't think I'll have the problem he's having though. He gets 145mpg and I'm only getting 90+ mpg so he's using EV more often than I am.

 

I'm a new 2011 Prius II owner and am observing the same thing regarding an early low fuel gauge warning. Takes ~9.5 gal at the zero gas indication, but the manual says the tank carries 11.9 gal. In prior cars that meant I had perhaps 50-60 miles left, but with the Prius, I might have over 100 miles of travel! It will take a while to figure out how to adapt.

 

Keep in mind that fuel tanks are rather flat, long and somewhat wide. The fuel pump is at the bottom but rarely does the intake sit super flat against the bottom of the tank. Now imagine an empty tank, then fill it with 2 gallons of fuel. That fuel will spread out over the bottom of the tank and may only be 2"-3" deep due to the flat wide bottom surface of the tank. In this case you have fuel in the tank but some of it may not be reachable by the intake of the fuel pump. So I then have to ask is the entire 11.9ga fuel capacity usable?

This is purely speculation on my part because I have not seen the tank in person but with other fuel tanks I have worked with my observations pan out.

 

A little example - see 2 pictures attached.
One reads that currently I have 197km to "fuel up".
The other one reads the km and consumption since my last tank (full to the first click). Usually after it clicks I can get maybe another litre in, not more (about 1/4 gal - the speed at which the pump "shovels" in the fuel makes the difference on how much you can still put in after the first click and how the pump is set up, IMHO).

So now, with a bit of calculations we get that:

litres used so far (considering that the MFD is, say, 5% generous - actually mine is 6%) ?
4.1(L/100km)*1,06=4.346(L/100km) --> 23km/L --> 628/23=27.3L

Litres left in tank?
45L-27.3L=17.7L

Km to empty (assuming I keep the same fuel consumption so far)?
17.7(L)*23(km/L)=407km

Difference to "distance to fuel up"?
407km-197km=210km!!!!!

So the "distance to fuel up" tells me 210 km in advance that I need to fuel up!!! WTH!!! 210km/130mi means about 9L/2.4gal of fuel still in the tank!
I will get nervous days in advance for fearing of being left dry, 200km before it happens!