[Blueji]

So my gas gauge has said “full” for over a week now. It makes zero sense to me. I just now noticed it and I’m freaking out because I don’t have money at the moment to get my car fixed. I have the Fortwo 2013 coupe.
Please help me figure this out. 🥺

 

[jwight]

How many miles have you done since filling the tank?

 

[Laughing Crow]

I have noticed that the gauge on my 2013 seems to not move for a while then suddenly it's down a quarter tank. Fortunately, the lower end of the scale seems more accurate. You could fill it again and see how much you have actually used at his point

 

[OliverB]

Most gas gauges are not linear, meaning they do not read accurately as the gas level goes down in the tank. One cause may be the irregular shape of many tanks. Another cause may be the design of the sensing unit in the tank.

 

[smark]

To the Op. nothing wrong with your gauge. The fuel gauges on the 451, aren’t accurate at all.

 

[John Phoenix]

It's a 10 gallon tank essentially right.. 8.7 main tank with 1.3 reserve. I'd put a couple of filled gas cans in the car and run it till you run out of gas. Write down the mileage. Fill up the tank with 10 gallons if possible and go from there. This way you might get a better idea how your gauge behaves as well as check the MPG.

 

[TheRealElbadoo]

It's a 10 gallon tank essentially right.. 8.7 main tank with 1.3 reserve. I'd put a couple of filled gas cans in the car and run it till you run out of gas.

I wouldn’t recommend riding around with gas cans in a car if I could avoid it. I don’t like doing it in a sedan with a trunk and certainly not in my ForTwo. Your car’s gas tank is designed and located with some measure of impact, vapor, and flame protection in mind. A loose gas can? Not so much.

If you’re concerned that the gas gauge isn’t registering properly, you should go refill the car’s tank and see how much you’ve actually used.

If it’s only a gallon or so then you might be worrying prematurely. My 2009 Passion doesn’t start registering until after 75 or so miles, but then becomes more accurate the rest of the way down.

After refilling, zero your trip meter and then watch the gas gauge over the next 250 miles. You should eventually see it move, and will learn your individual car’s behavior. If it still doesn’t change, THEN you may have a problem with the sensor that needs to be checked out.

 

[Miss Mercedes]

You also don't want to run your fortwo dry. Some people have run their cars dry and not only needed gas, but a fuel pump, too.

 

[Jo e Lefors]

You also don't want to run your fortwo dry. Some people have run their cars dry and not only needed gas, but a fuel pump, too.

Agree
Running a tank dry only to prove a known value, smart 451 gas tanks are 10 gallons isn't a smart idea. Fuel cools the pump.
If you want to be overly conservative consider a 10 gallon tank at 30 miles a gallon you've got 300 miles. Somewhere between 250 miles and 300 miles you should plan on getting fuel. Your smart has a trip odometer.