Fuel gauge and total miles question

[miloca1983]

04 murano driver here

question


When i went to gas up my car i checked the total miles on the computer it said it had 40 miles left in the tank but the fuel gauge was under the E and the fuel empty light was on. Is it right that i had 40 miles to go before the fuel tank would go empty or is something miscalculated with the computer?

[HVT]

Those aren't meant to be exact. But they are usually in the ball park. 40 miles left would be about 2+ gallons. The light doesn't wait until you're completely empty to come on.

[BillArf]

On my 2011 Murano when the low fuel light goes on I have a little over two gallons ... actually about 2.5 gallons left in the tank. I have found that once it gets very low that the computer will no longer give me an estimate in regard to how many more miles til empty. No, I have never run out of gas.. but I know i have been very close. I do a lot of traveling across multiple states at a time..

[miloca1983]

Yes but does it really last the 40 miles?

Sent from my PC36100 using AutoGuide.Com Free

[hokey777]

When my '09 says I have **** miles left, It only takes 19 gallons to fill the tank. And I know it's not good for her, but I have gone 40 miles after the **** once.

[chuck jones]

Most of the responses told you that you have about 2 gallons left when the light comes on....but your question involved going UNDER the E...the computer quits calculating when the mpg or the # of miles left to go is less than 9 miles....you just get a series of - - - - on your readout. You're really pushing it at that point since there's no way to figure out what's left...except maybe sitting on the side of the road using your AAA card and a phone call.

I have gotten down to where the - -- - (last readout was 10 miles till empty) was showing on the readout but only one time. I can't recall how many gallons it took to fill it, but I think it was around 16....that's cutting it close. You will notice that there are times when the readout will tell you that you have...say... 40 miles left, but if you start driving at 55 mph, you'll see the number actually increase to 45 or more as the computer re-computes the mpg based upon your driving habit at that particular time....in other words, you're not using as much gas per mile so you can extend the travel distance by backing off of the accelerator. I've done that a couple times and it worked out well.

If you get to a station and decide you don't want to fill it,but for whatever reason you only put a couple gallons in it. There is a point at which the computer will not recognize the addition of a small amount of gasoline and will not reset the mileage till empty so you will get the same readout you had before you added a couple gallons. There's nothing wrong with the computer...it's just telling you you're a cheap sucker and like to live on the edge.....or that payday is tomorrow.

[HVT]

It's not good for the fuel pump to let it go that low too often anyhow. I'd try not to make it a habit. When you get low enough, stop at a gas station! They're one on every corner! lol

[miloca1983]

Im gonna do a test in the system, letting it empty all the way empty and post pics in here to see what the results are. ( and of course ill carry a couple of gallons of fuel just in case)

[BillArf]

Originally Posted by miloca1983

Im gonna do a test in the system, letting it empty all the way empty and post pics in here to see what the results are. ( and of course ill carry a couple of gallons of fuel just in case)

End result of your test will give you results as mentioned in the posts here. Light goes on and you have a couple of gallons left and you can go another 40 or so miles.

Indeed, best bet is to not let it run down low, low as the fuel in the tank cools the fuel pump, etc.. My post earlier mentioning I had experienced the low fuel light a few times does not mean I let it happen often and don't see a problem with it. Just find myself without a gas station late, late at night when I do my interstate driving.

[HVT]

Originally Posted by miloca1983

Im gonna do a test in the system, letting it empty all the way empty and post pics in here to see what the results are. ( and of course ill carry a couple of gallons of fuel just in case)

Why? What exactly are you looking for? You now know that when the light comes on, you have about 2 to 2.5 gallons and about 40 miles left. Why did you ask if you didn't want an answer?...lol...seems senseless. Keep letting it down to empty for no reason...you're looking for fuel pump issues.

[nitely]

Yeah, its not healthy for the fuel pump to be working so hard and hot---very low fuel--and higher chance for contaminants to clog up the lines.

I personally think that once you get the low fuel warning lite you only have 1-2 gallons left before the car stops running. Not much if you have big gaps between stations on the highway. The computer reading is an estimate which can easily change by using the AC. It will drop drastically when the AC is running high and sitting on traffic. Try it.

When your gas guage reads E then its time to gas up. No matter what the dumb computer reading says. Its always better to keep a full tank of gas than an empty one. Your fuel system will run trouble free much longer this way. BTW, I believe in using some fuel system cleaner poured in the gas tank 2X a year atleast. (like chevron techron fuel system cleaner concentrate) Helps clear carbon deposits on the injections.

[hokey777]

Originally Posted by chuck jones

I have gotten down to where the - -- - (last readout was 10 miles till empty) was showing on the readout but only one time. I can't recall how many gallons it took to fill it, but I think it was around 16....that's cutting it close.

Close? It has a 21 gal tank.

Originally Posted by HVT

It's not good for the fuel pump to let it go that low too often anyhow. I'd try not to make it a habit. When you get low enough, stop at a gas station! They're one on every corner! lol

True, but when you are out in the middle of nowhere, there are no corners.

[Pilgrim]

Originally Posted by HVT

Those aren't meant to be exact.

That sums it up. Don't worry about it. When the gauge is low, fill up.

Originally Posted by miloca1983

Im gonna do a test in the system, letting it empty all the way empty and post pics in here to see what the results are. ( and of course ill carry a couple of gallons of fuel just in case)

Feel free, but it's a total waste of your time. THESE SYSTEMS ARE NOT EXACT. They are not going to be exact...so there is no point in expecting them to be exact.

When your gas gets low, just FILL UP.

And the others are correct - fuel pumps are typically located inside the fuel tank, and it is assumed by the designers that you will keep some gas in the tank around the fuel pump to cool it down. Running the fuel tank empty heats up the fuel pump and can contribute to early failure.

Seeing as how the exercise has no value, I don't see why you would want to do it.

[miloca1983]

hmm.. ok i was just curious because my brother has an 2010 armada and that computer actually displays how many miles he has left in the tank before his truck shuts off.. but you are all correct that's just damaging the fuel pump. And since pilgrim put so eloquently "These systems are not exact" i see no point of doing it

[Pilgrim]

You are a wise man!

And just think, now you have more time to drink beer!