Actually, that shows that it's pretty accurate, rather! As a matter of fact that's how I got the idea of the sensors. .... some sort of 'holes' , once the level dips below and uncover them, the fuel gauge light comes on. And if you're parking down/uphill, the level will rise and cover the sensor and the fuel gauge light will go off. Actually, it should be a trouble shooting procedure for your fuel gage light !!!!!! LOL .... I'm having fun now ...

Well, I was curious how some of U calculate their mpg ... not that I really needed to know how ... I appreciate all the answers though.

 

What are you talking about?

It uses a float on a stick. h: It's inaccurate as hell and even varies from one vehicle to the next. Some are even moody. All the float on a stick does is tell you when the float gets low. You could have 3 gallons of gas left in it when it comes on. Enough to go over 100 miles in a SOHC civic. Not an emergency.

If you want to know exactly how much fuel is in your tank, it must be calculated by weight like it is in aircraft. You don't drive a BMW 7-se ries, so your car is not equipped to do this. If you have that weight, then your approximate range is easy to calculate based on your average MPG.

If you want to know your average MPG, then

(miles per tank) ÷ (gallons until filled) = AVG MPG

You'll figure out how far you can push it. Don't worry about that BS light. Seriously. Figure out how many miles per tank you usually get and go from there.

 

Holy cow this ended up being one of the weirdest threads in a long time. Does it actually REALLY matter if the light comes on at 2 gallons or 3? You shouldn't be waiting that long in any case because the fuel pick up will start to suck up crap at the bottom of your tank clogging your injectors and your fuel filter.

http://auto.howstuffworks.com/fuel-gauge.htm

 

No light for me. I'm glad. I think it would annoy me.

 

So many people think they need to fill the tank and then go drive it off to see how far they can get on it. What needs to be explained is that you are starting full, then driving, THEN measuring the amount of the re-fill-up. Not lecuring you guys, It's just frustration from trying to explain this to my idiot friends. :slap:

I'm going to piss someone off here I'm sure.:yes: This is just me so no lectures. My Civic VX has the 11 gal tank (or whatever it is). I run it just about all the way down every time unless I know that there is a good gas price (cheaper near my home) or I know that I'm going to be going to work and need to go 100 miles without taking a break. I get to the "dregs" of the tank nearly every time. (P.S. I'm the same guy you guys got pissed at for not changing my fuel filter, and yes, it's still filtering). I hit the trip meter each time I fill up and use my fuel gauge and trip meter together to know when I need gas or to know how I'm doing. I also know that the one pump I like near home angles my car away from the pump and I can get maximum gas in there. My car has no gas light, but I'm sure it's just part of the fuel sending unit (the stick with the float). It has a variable resistor on it. Electricity is sent to the sending unit and depending on how high it floats in gas, a variable amount of electricity makes it back to the fuel gauge. The gauge on your dash takes that "leftover" electricity and uses it to warm a bimetal coil connected to the needle to make it move. That's why when you turn your car off it goes down slowly or when you go around a cloverleaf, :wiggle: the gas is riding in the side of the tank and makes the sending unit ride higher or lower and your gauge slowly rises or falls when you come out of the turn). When you get low on gas, The same sending unit just sends a voltage that the low gas light picks up on.

For me, I keep a little note book in the glove box. I keep notes in it of ALL maintenance I do to the car on the left page. On the right page I keep track of every time I get gas (The top of the right page is where I put when the oil change is due). On the fuel page, I have columns of date, mileage, gallons, and MPG. Write it all down! I'm on my 3rd book this car and I have one from every car I've owned.

The first guy to reply had it, :goodjob: but now that you have all this data on paper, you can add several pit stops together and get a better idea of your average MPG. Take the miles you drove over several or many tanks and divide by all the gallons you used on all those tanks. This will compensate for all the variables you have from different pumps.

Discuss...:blah:

Doesn't gas always come from the bottom of your wether the tank is near empty or not? Do you think the inlet to the fuel pump floats? NO:wavey:

 

I have my car tuned to provide best gas mileage and power but I can't run anything other than 89 octane unless i compromise economy or power... cam & ignition timing really does make a difference.

 

geez this is something they teach in driver's ed

 

THIS IS driver's ed.

 

Just to add to that, your gas light and gas gauge are going to be much less accurate than the gas fill pump's gauge. And if you use the same gas pump each time you fill up, the auto shut off mechanism is going to be consistent from time to time (since it measures air flow rate out of your tank to shut off the pump). So, I would trust that more than your gas gauge.

 

speaking of airflow out of the pump.. what happens if you continue to pump some more of the extra bit of gas in the tank to the point where it almost tips out? Obviously there isnt much of any air by doing that but, is the air in the tank needed?