Accuracy of Fuel Range Estimator

[csmiller218]

I have an '06 Murano I just purchased. The tank size is 21.7 gallons, but when the range estimator on the in dash screen goes to zero, it only fills up with about 17 gallons. Does anyone know how much further you can drive before getting close to empty--say within one gallon? Is it about 60 miles or so? I haven't tried, but didn't want to get into any trouble by going to low.

[BBISHOPPCM]

You typically have a reserve of about three gallons, I would ignore the range estimator and focus on the low fuel light; when this light goes on, count on roughly 40 miles of driving distance. I do not recommend "testing the waters," as low fuel can drastically reduce or kill the in-tank fuel pump, since the fuel cools and lubricates the pump.

[viperdoc]

Kind of and intersting tidbit....I actually try to fill up when my car hits halfway empty (or halfway full depending on your disposition). I read a review about gas mileage and it said that the lower your tank gets, the more gasoline you lose to evaporation in the tank itself. Apparently, as the gas level goes down in the tank, the vapor pressure above the gas level lowers, which prompts more gas to evaporate, raising the vapor pressure back toward equilibrium. Kind of a nerdy answer, but I have tried filling up at halfway vs waiting until almost empty, and my gas mileage gets MUCH worse if I wait, even given the same driving habits. Plus is makes sense from a physics point of view. This principle is apparently why the gas tanks at gas stations (the big ones underground) have "movable ceilings" so that as the level of gas goes down, so does the ceiling of the tank, so the vapor pressure stays constant and you don't lose much to evaporation.

[Poyzinous]

The Range estimator is tied into your drive computer's variable parameters for Fuel economy and average speed. It will change once it realizes that mathematically, its not making sense. For example, the same system is in our Pathfinder, and after a full tank of city driving, and average economy of 16.5mpg, the range estimator will say 280 miles at a full tank, but after traveling 120 miles on highway with 22 mpg, It will say 190 miles range when you reach half tank, as opposed to 140 miles if you do direct math.