I heard someone say that the coupe has a "gas reserve", of sorts, in the tank. In other words, the tank holds 20 gallons, but gauge will hit "E" when there are 4 gallons remaining-as such, the fuel gauge shows the relative supply remaining, of the 16 gallons, not 20.
[ each "quarter tank" marking on the gauge = approx. 4 gallons]

Is this true?

It would be good to know, in order to better "ballpark" gas mileage.


(I tried a search, but came up "empty"

thanks in advance

 

well gas mileage shouldn't matter in this situation. The only way to figure out mileage is to divide the number of miles driven since last fill up and how many gallons it takes to fill back up to the top.

I tested my navi last week because some people claim the nav is unreliable. It gave that i was getting 18.1 MPG and when I divided the number of miles by the gallons I got that exact number.

On the reserve question, I don't think it has a reserve, but the E light will come on when you still have a few gallons left to warn you that you are low.......all cars are like this.

 

Sure it matters.

If the gauge is in fact based on 16 gallons, ( "F" indicating 20 gallons, "E" indicating 4) then each "quarter tank" marker represents 4 gallons, so you can, as I said, "ballpark" your gas MPG, without waiting to refill the tank to calculate MPG exactly.
[Obviously, if the gauge indexes the full 20 gallons, each quarter will = 5 gallons]

This also might help keep track when the tank won't fill completely, which seems to be a problem at times.

 

Well, a few times I had the gas light come on and within 5 miles I went to a gas station (both times I was on my way to one anyways) and it filled up a little over 17 gallons. So I assumed it came on at 17.

The last time it happened right on the offramp, and when I got gas it filled up like 16.05 which made me think it comes on at 16 now and I was mistaken, so it seems to be one or the other.

I just go with knowing I have a solid 55 miles ( about 18mpg * 3) once it comes on.

 

You've got only 20 U.S. gallons from empty, and the Low Fuel light comes on with approx. 3 gallons remaining.
Mine comes on with about 4 remaining but the light isn't very accurate.
C.

 

no, im saying your MPG has nothing to do with it....anyways I don't think you can base each marker as how many gallons you have left. In every car I have owned it seems the last half of the guage always goes faster. I can get almost 200 miles on the first half of the guage, but a measly 100 or so on the bottom half.

 

I think the point ChazM was making is that you don't have to wait until your tank is empty to figure out the mpg's. I, for one, never let my tank go below 1/4 tank. But what I do is fill it up and divide the mileage. For example, this morning I filled up my tank with 15.342 gallons and I went 301.6 miles since my last fill up. 301.6/15.342 is about 19.6585 mpg. You can do this at any point as long as you keep zeroing out at least one of the odo's with every fillup.

 

It just so happens that I drove my car with the gas light on for about 20 miles, went to fill it up and it took 16.1 gallons. I was really surprised that is all it took and this is the first time this has happened I always fill it back up before it goes below a 1/4 tank.

 

I don't worry about it, I just carry a siphon

 

That last bit of gas below the empty mark is so you dont aerate (suck air into) your high dollar electric fuel pump; the fuel actually lubricates the pump, air will cause very minor damage EVERY TIME you run it that low. Did you ever ride in someone's car or truck and can actually hear the pump running; that is the first signs of damage done; fuel pressure also begins to suffer.

Keep the pump in good shape; change the filter on time and never run the tank until it's empty... I always hit the first station I see if I happen to get low enough for the low fuel light to come on; I usually try to get gas in the tank somewhere right below the 1\4th mark.