Gas Capacity

[Campingfamco]

When I bought the Denali I didn’t buy it thinking I’d be getting great gas mileage. What I didn’t think about was the 24 gallon fuel tank. originally I thought if I got 15 MPG on average and say used 23 gallons of gas I’d have a range of 345 miles. Well the other day I ran it down to where the tank showed no gas on the gauge, which is really hard to tell on the display, and then the low fuel light came on. Typically this means you have 30 miles left.

I drove for about 25 miles in the same driving conditions and when I filled up, it only took 21 gallons. That was after filling it up, waiting 1 minute, then slowly trying to top it off. It was 20.5 gallons before that.

I’m curious if anyone else has experienced this. I find it hard to believe three gallons of gas is in the fuel lines.

Thoughts?

 

[OR VietVet]

First, running the fuel down that far causes the fuel pump to run hotter. The pump likes to be submerged in fuel to keep cool. I don't recommend running any rig below 1/4 tank and I consider that as EMPTY. Secondly, you should not top off fuel till it is right at the top. That can do damage to the evap system. You have to remember that the gauge is reading fuel at the very bottom of the tank that when is that empty, is sloshing around from side to side and can mess with the readings. Also, the pump assembly does not rest on the bottom of the tank and therefore some of the fuel that is at the bottom never gets read for the gauge.

Clear as mud?

 

[Doubeleive]

fuel tank capacity will be listed in your owners manual, it varies from model to model.
also in the dic you can view the "estimated" miles remaining, even after the fuel light comes on until it gets to low for it to calculate
I believe when the low fuel light comes on you still have around 5 gallons remaining
As for Ron's statement I suppose you "could" damage the pump by running it around empty ALL THE TIME, not in general from just running it from full to near empty as normal operation.

 

[gooffeyguy]

I know not the same year/generation vehicle, but my low fuel warning doesn't come on until the gauge is just on the E, or a hair above it, and I usually have about 6-7 gallons left. 31 gallon tank.

All vehicles are different though, just got to figure what yours does.

 

[Kpwweb]

First, running the fuel down that far causes the fuel pump to run hotter. The pump likes to be submerged in fuel to keep cool. I don't recommend running any rig below 1/4 tank and I consider that as EMPTY..

Mostly true. The new pumps and tanks have a “reservior” around them for cooling. I.e they are designed to keep about 1 gallon of fuel around the pump at all times for cooling. It was interesting to see when I dropped the tank on my 2016. I’m sure the 2021 is the same way.

 

[OR VietVet]

fuel tank capacity will be listed in your owners manual, it varies from model to model.
also in the dic you can view the "estimated" miles remaining, even after the fuel light comes on until it gets to low for it to calculate
I believe when the low fuel light comes on you still have around 5 gallons remaining
As for Ron's statement I suppose you "could" damage the pump by running it around empty ALL THE TIME, not in general from just running it from full to near empty as normal operation.

Yea, I should have been more clear about that. IMO, on a regular basis running it close to empty does cause a problem with fuel pump cooling, at least on the older systems. Like @Kpwweb said, GM has now designed a reservoir around the pump for fuel to help keep it cool and I am sure that was designed that way because of what the old design caused for the older pumps. Being old, I just am used to recommending the tank never be ran below 1/4 tank. Makes me feel better at least.

 

[Doubeleive]

I will add that "how you drive" will also determine the remaining mileage once the fuel light comes on I tend to have my foot in it so most people will get farther than I would, when I had my 03 Silverado she was a testy ***** if the fuel light came on you had better find a gas station quick because you were not going to make more than 5 miles even if you baby it. It would let you know you too if you accelerated too quick she would sputter and die out and then fire back up a few times I had to gas/brake it to shake the tank and get into a station.

 

[OR VietVet]

Like NASCAR when they are steering back and forth on the caution laps to be able to get back to pit road to get fuel.

 

[gooffeyguy]

Like NASCAR when they are steering back and forth on the caution laps to be able to get back to pit road to get fuel.

I thought they did that to keep the heat in the tires and the gunk off

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[OR VietVet]

I thought they did that to keep the heat in the tires and the gunk off

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They do that too but I should be more detailed. They try to run below the apron and also wiggle back and forth. Up on the banking tends to pull fuel away from the pickup in the tank when at very low speeds. At full speed the fuel is still pushed to the pickup by centrifugal force. Sorry.