Is my gas tank 3/4 full or 13/16 full?

hmsminnow · #1 (**permalink**) 01-24-2008, 04:20 PM

I've searched TS and my owner's manual and can't find anything about this.
The fuel gauge in my CrewMax SR5 looks something like this:

E| ' ' l ' ' ' '|' ' ' ' l ' ' |F

Note that the "1/4" and "3/4" marks are off center. Does anyone know what these marks mean?

I figure there are two options:
Either the gauge is linear, and the Toyota engineers decided to mark it in strange fractions. (i.e. the needle moves at a constant rate as the fuel float moves)

OR

The gauge is non-linear and the marks truly represent 1/4 and 3/4. (i.e. the needle moves more slowly when the tank is near full or near empty)

I know there are gauges that do this. Many speedometers needles move very little until the car reaches 10 mph, and my Corvette's speedo needle moves twice as fast after 100mph (the tick marks represent 5mph from 1-100 and the same marks represent 10 mph from 100-Really Fast.)

Anyone have any knowledge on this? I know it's a minor issue, but I'm sure other people are bugged by it.

Stanton49 · #2 (**permalink**) 01-24-2008, 04:29 PM

Fill up the tank to maximum full and push your info button till you reach the range function. Note the range at full (mine's usually 380 miles). Then as you approach each "1/4th" mark note the miles left in range. Once you get to 1/4th full you should be able to determine if its 1/4ths or 3/16ths marks. Not 100% accurate but if your driving pattern is consistent, you should burn about the same #s of miles in each increment of the gauge.

cleoneo · #3 (**permalink**) 01-24-2008, 04:30 PM

Does it really matter?? Pretty soon the question becomes is it half full or half empty......

ag4ever · #4 (**permalink**) 01-24-2008, 05:15 PM

Does it really matter, pretty soon it becomes: does it have 6 gallons or is it empty?

crankytexan · #5 (**permalink**) 01-24-2008, 07:02 PM

Today when I went to fill up my truck it was past a 1/4 tank, but I only filled up 18.9 gallons. Granted the light hadn't come on, but in the vehicle that I traded this one in for if you didn't fill up after you went past the 1/4 you would be close to empty.

So doing the math Tundra has a 27 gallon tank 27 / 1/4= 6.75. So I had 8.1 gallons left just past the quarter mark. Something doesn't seem right if 1/4 of a tank =6.75 and I had 8.1 gallons left after being in the middle of E and 1/4 tank.

TundraBay · #6 (**permalink**) 01-24-2008, 07:08 PM

Quote:

Originally Posted by crankytexan

Today when I went to fill up my truck it was past a 1/4 tank, but I only filled up 18.9 gallons. Granted the light hadn't come on, but in the vehicle that I traded this one in for if you didn't fill up after you went past the 1/4 you would be close to empty.

So doing the math Tundra has a 27 gallon tank 27 / 1/4= 6.75. So I had 8.1 gallons left just past the quarter mark. Something doesn't seem right if 1/4 of a tank =6.75 and I had 8.1 gallons left after being in the middle of E and 1/4 tank.

Don't do the math. Tundra has a 26 gallon tank. If you're getting 15 MPG (as many are) the "low fuel" light comes on about 280 miles and "Range 0 Miles left" at 300 miles. At that point you still have 6 gallons left. You can drive about 90 miles and then the truck really stops.

Or if you want to do the math, make sure you have a jerry can with you.

Good luck

mike100 · #7 (**permalink**) 01-24-2008, 07:46 PM

I think it depends on if the float swings in an arc attached to a rod (where movement slows at the ends of its stroke or if it is a float that slides vertically on a rod.

the gauge could be enhanced to read non linearly to offset odd tank shapes far from the centerline.

lastly, the reserve of 4 to 5 gallons doesn't seem to be part of the useable scale. I think the scale is for the 1st 20 gallons and that it has a float that swings on an arc.