Folks,

Noticed something with my gas consumption. I drove from NC to GA yesterday (~240 miles - cruising at about 80) and burned about to the halfway point on my gas gauge (filled up before heading out). This morning I drove to the airport (~80 miles round trip, probably 65 are highway - conservative driving), and the gauge was saying that i burned an additional quarter tank.

I read in a post somewhere that the first half of the tank is more efficient than the second (due placement of the fuel pump maybe), but by this much? Anybody else notice disproportional between first and second half of the tank? And is there anything I can do to fix this?

Eenis

 

big difference, i believe it though, all my previous cars did the same, i think it has something to do with when u fill it all the way up, it goes past what the gauge can measure. So u need to burn more gas to get the gauge to actually go down, not sure if this makes sense or is right.

 

I've found to not look at the lines on the gauge. I go by when the needle is straight across, I'm at a half tank.

 

Why do you people notice the weird things Now your gonna have to make me explain

Alright, first of all nothing is wrong, all cars do this...its normal.
There is a float inside the tank to let you know (fuel guage) how much fuel is in the tank.
When you fill up, the float will touch the top of the tank be4 the tank is actually full, probably another 2-3" left be4 your fillup is done and you cant take in anymore gas.
Now with that much more to go,the float is already touching and your still gonna fill another 2-3gal that the float will not register on the guage inside the car. While your driving around thinkin im getting some damn good mileage! Ive got almost 100miles on the 1st 1/4 tank you actually just burned the few gal of gas that was never registered on the guage.
After the fuel drops a certain amount the float will start to sink faster, thats why it looks like you get great mileage the 1st half (or so you think) but the after that it just falls.
There is no other reason this is happening and I hope this somewhat clears things up for you.

 

exact same thing on a snowmobile with the gauge that you place into the tank.

 

Much appreciated Hitman. sucks that they can't come up w/ something a little more accurate though. at least the needle doesn't float between empty and a half tank like it did in my mom's suburban.

 

Not a problem. If you think thats confusing I hope you never come across a problem with a float that has a leak. They will fill up with gas and it will always look like its empty It is accurate to a certain point. Atleast you never run out of fuel, its pretty accurate the last half.

 

So, does that mean that when the tank is full, the mpg reading on the dash is overstated a little? I'm not sure if the max uses the fuel level float to figure out the mpg or the actual fuel sent thru the injectors...

I would assume its not the float...

 

If you think about it, the opposite is actually true. You would get better gas mileage during the last half of the tank because the car weighs less the more gas you burn.

Tony

 

Im not 100% sure, but im betting its the ECUs reading of how much fuel has gone through the injectors. Its too innacurate to go by the float.

Tony:...Comon man, why? why make things more complicated?