My non NAV TCH has the yellow low fuel light come on half way between the last qtr tank and empty markings on the gauge. At that point the estimated cruising capacity is 35-50 miles. If I ignore the yellow fuel light (which Toyota does not recommend) and drive till my cruising range reads 0 then the needle on the Fuel gauge rests on E.



My questions are:

• What is the remaining tank capacity when the fuel light comes on?<
• What is the remaining fuel amount in the tank when the cruising range shows a reading of 0?<
• Can one take a risk and drive say 20-30 miles even when the cruising range reads 0?<
• Why does the fuel light come on so early and is discordant with the remaining cruising range?<

 

I'm not sure about the first question, but when the display reads 0 mpg to empty you have about 3 gallons left. That leaves you with another 100 - 140 miles depending on your FE.

 

There could be variations between particular cars, but around 3 gallons are left when range shows 0. But you should check it yourself, to make sure your car is the same as most. Tank has 17.2 US gallons capacity, all you need to do is pull up to gas station when it shows empty and fill up to see for yourself. If the car takes lets say 14.5 gallons you know you had about 2.5 gallons left in the tank, good for about 75-100 miles. It's not good to run the tank dry so if the instruments show you need gas don't drive for another 100 miles untill it's totally empty but at the same time don't panic the car will stop dead any minutte now. BTW I drove some places where the next gas station was 100 miles away.

 

And as a general rule, NEVER use the last 1.5 gallons in your tank. Over time, a lot of crud accumulates there. My mechanic showed me once when he pulled out a fuel tank on a 5 year old car, it was FOUL.

 

Jeff, thanks for the info, but I never let it get down there. The most I've ever put in the TCH is about 14.5 gallons which left over 2.5 gallons.

 

I dont know the specifics of gas tanks and such, but wouldn't the vehicle be getting gas from the bottom of the tank anyway? I guess the other option is to have some floater in the tank with a tube connected to it so that it gets the gas from the top and works its way to the bottom.

 

Food for thought, your fuel pickup is located at the very bottom of the fuel tank, so if there is crud in the tank, it will be picked up by the fuel pump even when the tank is full. I would bet that the reason the tank was out of that 5 year old car was due to bad gas. I have seen a number of fuel tanks out of cars, and most all of them are increadibly clean.

The main reason to never run the tank to empty is that the fuel is used as a coolant to keep the fuel pump from getting to hot and "burning out". If you run the pump without enough fuel or even run it dry you will severly shorten the life of the fuel pump. As a general rule of thumb, it is best to keep the tank at least 1/4 full, but I typically run mine as low as possible since I drive so much. I want to visit the gas station as little as possible.

I hope to do that now since I just got rid of a Land Rover Discovery that got 14 MPG on a good day using premium for my TCH.

 

Back a number of years ago I used to fly small aircraft and the lowest point on the tank was a drain to remove water due to condensation. It always amazed me how much water accumulated from day to day. Obviously an aircraft goes thru a much wider pressure and temp change then a car, but I had always assumed that the pickup on a car was slightly above the bottom just to avoid such a thing.

 

On my truck there is a depression in the bottom of the tank where an "inverted" cup is placed with little serrations at the edge that contacts the tank. This ensures the fule is being drawn from the bottom of the tank. It is a diesel truck, and fuel foaming is a concern so they might have designed it that way to ensure it picks up non foamy fuel. Also diesel is much more prone to biological growth than gas is, but it is still very rare to have a nasty tank.

The last gas tank I was in was on a '93 dodge, and the intake was right at the bottom of the tank.

I personally think the reason airplanes have the intake a little higher than the bottom is risk factor. If there is some water picked up, it would be very bad in a plane, but in a car you don't have the same exposure. Also a plane is much more prone to water in the tank as it is constantly flying into cooler air causing the water in the air to condense, and the bladders in a plane's wing is more prone to "hiding" water. That is why you are supposed to rock a plane around to drain all the water and slosh it out of the little pocket it could be hiding in.