Toyota RAV4 Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hi, just bought a new 2017 Rav4 XLE a few weeks ago. I've put about 400 miles on the car so this may be a little premature but was hoping some people who have experience with Rav4's could give their knowledge.

I've been averaging 25+ MPG and I know the tank is 15.9 gallons. For some reason the fuel range to empty at a full tank is only about 310-320 miles. Right now I am at a half tank and fuel range estimate of 149 miles. Doing some simple math on that doesn't make sense and seems way too low. That would imply it is guessing a 20-21 mpg.

Does it take a while for the computer to learn your average MPG and my fuel range will start growing the more I drive at better mpg? I drive pretty conservatively and have been running more in the 28mpg range lately. My old 2009 escape would do 400+ miles with a 16 gallon tank and worse MPG so this seems very odd to me.

Thanks in advance!
 

·
Registered
Joined
·
160 Posts
Those are decent numbers. I'm getting around 250 miles per full tank. well my wife drives the car during the week so really can't tell about her driving style.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
Wow 250? That seems awful. I think 320 is ridiculous. It has a 15.9g tank. Assuming even 25 mpg which I have been doing better than and is the combined avg advertised, the avg should be closer to 397. I took a little off for "reserve" and still the math seems to indicate the estimated range is too small.
 

·
Registered
Joined
·
160 Posts
I have no complain she doesn't drive much. I fuel it up every week and still have 1/2 a tank left. If remember correctly is giving me around 22mph.
 

·
Registered
Joined
·
1,912 Posts
I've been averaging 25+ MPG and I know the tank is 15.9 gallons. For some reason the fuel range to empty at a full tank is only about 310-320 miles. Right now I am at a half tank and fuel range estimate of 149 miles. Doing some simple math on that doesn't make sense and seems way too low. That would imply it is guessing a 20-21 mpg. Does it take a while for the computer to learn your average MPG and my fuel range will start growing the more I drive at better mpg?
I'm not an automotive engineer, but based on my observations, I don't think the system uses your average MPG on the current tank to calculate the range. How could it possibly know what your average fuel economy will be at the time you fill up.

My experience is that it calculates the average MPG during the last 20 miles. (approximately) along with the current amount of fuel in the tank.

So when you first fuel up, your range would be calculated on the last 20 miles driven. If you just pulled off the highway to get gas, the estimated range would be quite high immediately after the fill-up. As you drove through stop & go traffic you would see the range drop faster than the actual miles driven. If you once again get on the highway you would see the range start to increase despite the fact that you are actually consuming gas.

In my own vehicle (not a RAV4 BTW) I often take trips of several hundred kilometers and the estimated range shows that I have enough fuel to return home. However after driving around the town for a few hours the estimated range drops so low that I would not be able to get back home without refueling. But once I get back on the highway for several miles the range gradually increases as I drive further until the estimate is high enough to get me back home. At some point the estimate stops increasing and begins to fall as expected.

Another thing that you might consider is that usually the low fuel warning light ("the reserve") will come on when only 10% of the fuel is remaining. So in the case of a 15.9 tank, the light will come on at 14.3 gallons.I believe that the range estimate also assumes you will run out of fuel after 14.3 gallons. So if you were driving in conditions to give you 25 MPG for the entire tank, then your estimated range would be 357 miles.

EDIT: A Google search comes up with a lot of theories, but it seems most of them agree with my "last 20 mile average" theory.
 
1 - 6 of 6 Posts
Top