Fuel tank size and mileage confusion

With my new 2018 CM 1794 RWD being about 3 weeks old now, something is not adding up.
I just did my 3rd tank fill this morning. The dealer filled it up when I bought it and I did the 2nd fill.
Here's where it gets confusing.
My full tank range says its about 640 mile range, ok, x 2 should be about 1300 miles. I have about 950 miles on it now. (ok, who stoled my 350 miles) When filling it up today (3rd fill) it said i have only 34 miles before empty, ( this would mean I should have about 2 gallons of fuel in the tank) I filled it up expecting to pay for about 36 gallons in the monster.
Nope, she only sucked down 30.1 gal.
So, with a 38 gal tank, only taking 30.1 gal, this would mean that there was about 7.9 gal in the tank. 7.9 x approx 16 mpg (I've been gentle) what the computer says, but it should be reading about 126 miles left before empty but showed i had 34 mile range before empty.

After this 3rd fill, i set the trip A and B to 0, it says my range is 572 ( which now seems to be lower than the first 2 fills.

Does any of this seem off?

 

Math seems right

 

Seems right to me and that is exactly how mine is. If I run it down to where it says 0 range or the fuel light comes on, I usually put in 30-32 gallons.

Our 4 runner is the same way but not quite as many gallons left over. Once the low fuel light comes on we still have about 3 gallons. Same in our Honda Accord.

Could you imagine if the range really was based on the true gallons? In other words once the range hit zero that was 38 gallons. Considering about everyone in America runs it until their fuel light comes on you would see Tundras all over the side of the road out of fuel.

Did you calculate your mileage by hand?

 

Not yet, But this tank will be calculated, I promise ,

 

Download the fuelly app. It is free and is great. Also good for charting maintenance also.

 

Thanks, I'll check it out

 

38 gallon tanks gas lights come on at 30 gallons and 26 gallon come on at 20...well known...

 

Good to know. The light never came on this morning. But, the milage range said 34 and the needle was showing about 1/16, I surely didn't want to push the Behemeth. I'm too old for that S^&#.

 

Gotta have a ample safe guards built into gallons & miles to go. The average level of stupidity is high. And getting higher.

 

All of my Toyotas have done this to some extent.

Not sure what determines the 0 clock or the gas light but I've always referred to this as my "war time reserve". There is where you turn the chopper around and then there is how long you can actually loiter. ;-)

 

I think this was intention. 38gallon fuel tank, light comes in at 30 gallons. Leaving 8 gallons.
Assume your towing a trailer up a hill, worst case scenario 5ish miles to the gallon. 8x5=40 miles...the average for a light on. The moral of the story is your all assuming mileage based on perfect scenarios, not all scenarios that the engineers thought of.

 

To the OP...The story I've always read on the forums is the fuel pump is cooled by being immersed in a large fuel reserve inside the tank.

There is nothing to keep you from using that large reserve in an emergency, but maybe not advisable to do on a routine basis. You are also pretty much flying blind without indication of range unless you calculate from past experience. It's not like the small reserves of the past...I'm just the messenger.