Fuel gauge way off

have they tried resetting the inclinometer? if not, maybe suggest it. it can cause some strange fuel gauge action.

 

I think it just goes to show that it pays to fill up when low. Why try to calculate when you have a nice display that should tell you when it's time. At any rate, it certainly seems like it was accurate in this case, since they did determine the tank was empty.

In addition, I'm not sure I understand your numbers..

1. Car says you need to fill up - you feel you have 200 miles to go still (big assumption since bladder and fillups from pumps can cause 3 gallon variances at times)
2. You add 7 gallons
3. At 416 miles, you run out of gas.

I'm not sure I see that there's a problem at all. Here's Why

1. Maybe with your last fill up, you didn't put in quite as much fuel, so the tank wasn't really full, so you didn't really have 200 more miles to go.
2. 7 gallons - would seem to indicate 3 gallons in tank, but that's not always the case
3. Assume 50mpg. That would be 350 miles on the 7 gallons you put in. We at least know the tank had that much in it. You went past this by 66 miles. At least another gallon.

So - Things seem to add up in my opinion. If you are so determined to fill up based on the odometer vs the gas gauge, keep a log of fill ups so you know how much went in each time and how many mpg you were really getting.

The one missing number from the above equation is how many gallons did you put in at the previous fill up? Either way, this doesn't seem that far off.

 

OHHHH...

i didn't notice you were in MICHIGAN. it's starting to get cold again in the midwest isn't it? (i'm a WI native, should have thought of that)

yes, this will really affect your car's fuel bladder and you may have a hard time putting much gas in at once. here in nc is's still in the 80s (sigh) and i have a hard time getting more than 9 gallons in. i can see 7 being a pretty reasonable number considering the temp difference.

 

My fuel gauge is terrible- I can go almost 150 miles before 1 bar goes down, but after that, they start falling like bricks- I really don't like that- but I deal- I have just learned to get gas at half tank.

 

You have probably never owned a car that didn't behave this way. However you probably never noticed or cared. The only reason you notice it now is that you are constantly watching your MPG, miles driven, and you fuel gauge. This is something you probably never did on you previous car.

When I filled my old explorer, the fuel guage needle would peg on the stop pin well pas the "F", and would stay there for many miles before it started to drop. When I looked at the fuel gauge, I only cared about whether it was above 1/4 or below. If it was below 1/4, then I got gas, if it was above, then I didn't. I didn't track milage and I didn't have realtime MPG updates, so I wasn't sitting there saying "I know I've gotten XX mpg this tank and I've gone yyy miles, therefore I should be at 1/2 a tank, not 1/3".

You also have to consider that gas tanks are not perfectly square. Look at this one from an 87 Corolla:



The only way to get a perfectly linear gas guage out of that is to use considerably more complex electronics than is warrented for something as mundane as a gas guage.

 

It would seem to me that with computer power as cheap as it is these days, it would be possible for a car to do this reliably at minimal expense.

 

It just bugs me, because it does give me the impression that I can go far on a tank, and that I am getting great mileage, but then once it loses the first bar and just goes and goes, it's sad! That has been a complaint the whole time for me- that the tank doesn't go as far as I think a hybrid should- I can go about 450 miles, which for me is a weeks driving...

 

your guage showed empty and the tank was empty, in my opinion there is nothing more the dealership can do. Cold weather has a HUGE effect on these systems. I think you should trust your guage and ignore the math.

 

And filling up once a week is an issue? I used to fill every other day or so in my previous vehicle.

I think WAY too many people focus on the mileage than the fuel gauge. Fill up when the car indicates it's time! I just filled up today and I have over 4 bars! WOW, I muts be crazy :blink:

 

well, when the nearest gas station is 30 miles away- it's just a pain. I can only do so much driving before I head to the gas station.

 

Ah, isn't that the case with all of us. We can only do so much driving before we have to visit the gas station? I can do about 450 miles. That leaves me with 2 or 3 pips on the gage, and I'm happy with that.

Seems like a totally reasonable amount of driving to do between fillups.

 

30 miles away? WOW - I probably have over 15 stations I could choose from within 10 miles. Nearest is just 1 mile away.

I guess you need to move out of the boonies?

 

I had my tank ping 450mi into my tank (I'm in SoCal) when it's usually @ 500mi+ especially after I dropped in 11gals+ in previously.

So I decided to experiment a bit, and drove to 524mi without running out. And I know my run-out limit is usually 560mi. Then at fueling the first click-off was at 10.5, and the final fill was 11.8gals; my usual.

So there's some funny "memory" going on with the tank. It could be the cooling weather shrinking the tank.

I used to be able to get it to click off at 11gals+ in my Civic HX with its 11.9gal tank for the 199K miles I drove it, so I'm trying to accomplish the same here.

Things you might want to look at is maybe the fuel pump. Some are much too sensitive and click off too early. Experienced a few that clicked-off around 3-4 gallons.

Btw, my usual at half-tank is around 250 to 300mi in.

 

only 15, I'd hazard a guess that I could chose from at least 75 possibly more like 100+ in 30 miles.

 

part of the problem with the Prius gas tank and complaints is the tank only hold 1/2 -2/3rds the gallonage that your previous vehicle held and as such things happen faster. The top part of the tank in your other car was probably the total in the Prius and as such your thinking is wow I've used half a tank, in the Prius it's wow I've use a tank. In modern cars that fuel gauges are not very linear, as the tank is seldom a square or rectangular tank, like Marlin has pointed out.

 

Probably more, but I was giving a conservative guess.