When your MPG go up, does your cruising range go up like it should? Mine doesn't...I am so confused by this. My tank average has gone from 31 MPG to 37.5 MPG the same tank. Yet the Cruising Range never increases. So confused!

 

In 30,000 miles, I've never seen the cruising range go up, other than at fill-up time. I have seen it NOT go down for miles...when I am getting great mpg.

I've also seen it drop VERY fast near the bottom of the tank. I can leave my house with 14 miles to empty showing, and within a mile or 2, it shows 0...at the same time, the trip mileage in the ECO meter shows 35-40mpg!

I share your confusion.

 

It's a guesstimate based upon the amount of gas that it thinks is in the tank. I imagine when the tank is low and the gas swishes around in the tank, the meter can be fooled into thinking that there is more or less gas than actually is there.
But, at best, it's only a guesstimation. It's like trying to figure out which weatherman has the most accurate forecast for the weekend.
I never spend more than a half a second looking at the readout. I only look when I am cycling through to get to the one I want to see.

 

I don't think it's confusing. It won't go up (except at fill-up), but it doesn't go down either, when your mpg is good.

I filled up my TCH on Tuesday morning near my house, then drove to work. Since there was garbage traffic on the x-way, I took surface streets, and somehow managed to average 51.2 MPG over a 26.5 mile trip. When I filled the car up, the range was 515 miles. When I got to work, there was still 502 miles showing on the screen. So the computer thought I traveled 13 miles, but I really traveled 26.

I have also seen it drop very quickly when sucking fumes. It's gone from 10 to 0 in the span of 2 blocks in my neighborhood. I think it all has to do with the sensors in the gas tank. That seems to be typical of any car as well. Just because you have gone 300 miles in a half a tank doesn't necessarily mean you are going to go 600 for the tank.

Just my 2 cents...

 

The other crazy thing is a I filled up for the first time yesterday because the gas light came on, yet I only put in 13.9 gallons....I could have gone another 60-100 miles! Isn't that so early for the gas light to come on?

 

The low fuel light comes on when you have approximately 2.5 US Gallons of gas remaining. The overall capacity is 17.2 US Gallons. The remaining gas and what you added is 16.4 gallons... So you were close to the set point.

I think all manufactures do not want to risk the liability of the vehicle running out of fuel so the warnings can be a bit optimistic... And being on a slope can confuse them when the gas sloshes around in the tank...

 

Crazy?
No one benefits from running out of gas.
They are trying to prevent that from happening.
Many fill up as soon as the light illuminates. Some get very antsy driving with the light on. (My family yells at me when they see the light!)
If they prevent someone from running out of gas, I'd say that it's a good thing!

 

I guess it is especially shocking because my 1995 Honda Accord which I have driven for years and years before my new TCH wouldn't give me the gas light until I had been on E for 20-30 miles. My gas light came on for my TCH when I wasn't even on E yet. So when I filled up and realized I still had alot of gas left I thought maybe it was a malfunction.

 

I find that typically the low fuel light comes on at 1/8 tank. If I fill up then the TCH takes 14 gallons. Normally I go about 40 miles after the low fuel light before reaching E. I frequently will set the B trip and fill up when convenient after reaching E. If your curious, lookup my TCH tank log as I often note how many miles past E I drove along with the MFD mpg, gallons used, and cruising range after filling.

I find the cruising range does go up as the MPG goes up, but it appears to be weighted over a few tanks. I've seen it over 700 miles!

 

I think the logic is something like this. The low-fuel light comes on at around 1/8 on the gauge. The Cruising Range reading is designed to reach zero (and stay there) at about the time the fuel gauge reads 'E.' That's why it appears to plummet over the last 1/8 of the fuel gauge — the readout is being corrected to get to zero as the gauge gets to 'E.' The algorithm uses information accumulated over a number of tanks as the basis for your long-term average FE; this is what is used for the Cruising Range calculation. It learns how you generally drive, and uses this to predict the range! I have found that it does indeed make small adjustments upward, but they aren't easily apparent. It ceratinly does make large adjustments downward, especially towards the end of a tank.

The best way to see this in action is as follows: Set your Trip B, say, to zero at fillup. Then add the current Trip B reading to the current Cruising Range reading to get the current tank range estimate that the car computes you'll actually achieve for the whole tank. If you recompute this sum periodically, you'll see that the tank range estimate does increase when warranted. This is why you see that the Cruising Range reading sometimes seems to have stopped dropping (or is dropping only very slowly) as you drive if your current FE is high. It's really the sum of these two numbers that is most meaningful. It would not be a good idea to make the assumption that, because your current FE is very good, it will continue to be equally good for the rest of the tank. That's a prescription for potentially running out of fuel!

Stan