38 Gal tank experiences....

You are correct I’m not sure where I came up with the 30 gal tank I thought I remembered reading it in the owner’s manual when I first got the truck, I’m assuming I have the 38 gallon tank as I have put 30 gallons in it at its lowest point that I’ve driven it to, good advice through all of this to calculate mileage manually especially while towing etc. also good to know there’s a little more of a buffer from when the low fuel light comes on to when the tank is actually empty.

 

Technology is great, but it has made us forget how or why do things. My first car was a 1979 oldsmobile delta 88. It did not have a distance to empty display or a mpg display. Hell, it did not even have a low fuel light. I had to pay attention to the needle on the fuel gauge. I had to learn how much fuel that I had left (or how many more miles that I could travel) by how far the needle was over the "E". And I did that by hand calculating the mileage and using the odometer (This car did not even have a trip odometer). I did this hand calculation process with every vehicle that I have owned since. When I purchased the Tundra, I still hand calculated the mileage to verify those displays. I found that those displays were cool, but not 100% accurate. For me, the MPG display shows about 1-2mpg better than what I am actually getting. Also, the DTE display goes to zero way before I am out of fuel. I am sure the larger tires have also thrown those displays off.

 

Twice now, just filled and it was 34ish.

 

I put 32.2 in mine.... That was when the light just said refuel. And my CC maxed out so it may have been a little more.

 

sounds about right. i've only ever gotten to fill my truck up to just under 31gal since I've owned it.

 

Hand calculations can be far off also. Especially when you are down to the last little bit of gas (or last few miles, whichever way you look at it.) What do you use for MPG? It's a guess since you have no idea what MPG you will be getting those last 10 miles - you run into a traffic jam and stop-go conditions your MPG drops to 5 MPG and your calcs are not even close, while the computer will be recalculating as you go.

Bottom line, it is not possible to be 100% accurate, no matter how it is calculated, since there are way too many variables. Due to the size of the tank (actual length) when you are on a steep incline the amount of usable fuel will be a lot less than when you are on a flat surface. That alone will throw any calculation, manual or computer, completely out the door.

 

Hand calculations are damn near close to exact. If I drive 400 miles and put 30 gallons into the tank to fill it, then that is 400/30=13.33 mpg. It doesn't get much easier than that. Hand calculations show your mpg for the previous tank. It does not show your current mpg. However, I have done the hand calculations based on the different driving conditions. For example (in my Tundra), I know that if all the miles are highway miles, then I am getting around 15mpg. If the miles are city miles, then I am getting about 13mpg. If the miles are towing a travel trailer, then I am getting about 8mpg. I won't know the exact mpg in that condition until I full up the tank again, but I have a very close approximation based on previous fill ups. This hand calculated projection is more accurate than the truck's DTE or MPG displays.

 

I filled up my tank yesterday and put 31 gallons in. My needle was just above the empty line without the gas light on. That would imply 7 gallons till totally empty at 12 mpg. That’ll give me about 85 miles left to drive. It seems accurate to me and I believe that’s what my dash indicated as well.

 

I pulled up my fuel level gauge on OBDLINK the last time I hit Low Fuel (0 Miles) and it was around 6-7 gal left.

 

After the fact is accurate, but the response was on the discussion about remaining fuel and remaining DTE at any time. The computer keeps updating the DTE as you go; even if not 100% accurate, it gives an idea. Hand calculation can only be done after the fact when you fill up. While accurate, it does not help you when you are trying to determine how much further you can go before filling up.

Not a big deal, just saying.

 

I think that we are close to agreement here. However, I think that my current tank estimations (based on previous hand calculation history) are more accurate than the DTE and MPG displays. The DTE display goes to zero way before your are actually out of fuel.

 

Just to add on to your guys' discussion, a good point to mention is how the DTE only goes down and does not adjust. Say the first half of your tank is towing and you're burning through your gas and DTE is dropping. You drop off the trailer and jump on the highway at 65mph and cruise. DTE will adjust and begin to decrease at a slower rate. But it never goes up. My wifes accord will recognize the change in driving and increase. I'll fill up the tank and it'll show mid 400's DTE and jump on the highway and cruise easily and it'll increase to high 500's.

Hand calculations will still show my average for the tank and be very accurate but I won't know individually the mpg on different driving habits on that tank.

 

I just bought a 2021 Limited a couple weeks ago and it takes 30 gallons. I received a warning that I had low fuel with THREE MILES TO EMPTY. I went another 9 miles and was fine.
Does anyone know how to change the low fuel alert to something higher?

I am going to disconnect the battery and see if that helps as described above.

 

The one that gives me a reason to be upset of course!

 

15mi to empty only took 30 gallons and $80. Got 500mi out of the tank

 

16.666666666666666.... MPG

Impressive. Most impressive.

 

I ran mine about 30 miles after DTE went to zero and put 34.6 gallons in with 520 miles just yesterday - 14.9 mpg for the tank.

 

So has anyone figured out at what point do you expose the fuel pump within the 8 gallon reserve and damage it? 34 gallons of use? Etc?

 

Yeah. 1/2 of it was an out of town trip highway mileage

 

My fill up from last night

 

^^^ I'm guessing you're in Kali due to the 'Burrito' sign and the +$2/gal sunshine tax on the gas ;-)

 

There is no point of exposure in which you will damage the fuel pump (except for maybe running it dry). The fuel in the pump is what cools it, not the fuel around the pump.

Ask the Toyota mechanic! | Page 41 | Toyota Tundra Forum (tundras.com)

Ask the Toyota mechanic! | Page 41 | Toyota Tundra Forum (tundras.com)

 

Thanks for the info!

 

My Tundra is almost entirely freeway driven and it is definitely capable of getting over 500 miles per fillup. I go to the gas station at the half tank mark with 280 miles on the odo, and the ecu says I have about 240ish miles left.

When I drove from Las Vegas to the Bay Area and back, I filled up only once each way.

 

One hour ago, Filled 1/2 tank up at Chevron dealer.
Have the Chevron card discount too.
$94.68 which equates to $5.09 per gallon with discount.

 

The DTE calc for this truck is total BS. It's not dynamic. Someone else mentioned how other vehicles will add miles if you start doing highway driving. This one will not. The DTE is probably calculated at fill up, based on that last 100 miles or so of driving behavior.

Instead of focusing on the DTE calc, we should be focusing on the fuel low warning light. According to the manual, that light comes on when you have about 4 gallons of fuel left, regardless of highway or city driving.

Mine came on today and when I filled up ASAP I could only add about 31-32 gallons. So I had about 6-7 gallons remaining, rather than the ~4 the manual claimed. The DTE said I had 9 miles to empty. If DTE were accurate, it should have said I had at least 50 miles remaining at 10mpg being super conservative.

 

I don't want to pay more than $100, that's why I fill up before 1/4 tank.

 

That’s what I normally do, since it 4/gal i just fill up at half now and it’s still a grip. No complaints though I love my truck

 

Hell, here in California 1/2 tank cost me $98.17 for super.
Thank you sleepy Joe.