Fuel Warning Light - How many Gallons remain when comes on?

Gr8bawana said:

Has anyone ever read in their owners manual to never let the fuel get down below a certain level because the fuel pump will be damaged? No.
It just doesn't happen.
I don't know how this myth got started to begin with. Maybe if an electric fuel pump ran for a long time pumping nothing it might be damaged.

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At one time it was possible to damage a fuel pump if you let the fuel get too low. It was the early days of fuel injection, when the pumps first moved to the tanks - they weren't always sitting in fuel, which allowed them to get hot and wear out. It wouldn't happen right away but over time it absolutely would.

This was in the late 80's, early 90's, mind you - so it's been a LONG time.

GTyankee said:

I have not been any where, where there was a lack of Fuel Stations, i usually check my fuel gauge every morning.

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Come to Western Canada,there's lots of places where it's 60+ miles to the next service station,lol

Yeah, this has gone around many times here over the years with many of us being annoyed the gauge is so inaccurate.... as in when it says "E" its actually still almost 1/4 tank. Right when my light comes on it will take about 25.5 gallons.

I've never run mine out or even close.... most I've ever put in is 28 gallons but am supposed to have the 32-gallon tank. I really wish the gauge were more accurate. +/- 50 miles I get.... 6 gallons+ is a bit excessive.

Wild one said:

Come to Western Canada,there's lots of places where it's 60+ miles to the next service station,lol

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For sure. There are even quite a few places that are 150 miles between stations or towns and from 20:00 to 8:00 it can be 300 miles to the next one that is open.

Dean2 said:

For sure. There are even quite a few places that are 150 miles between stations or towns and from 20:00 to 8:00 it can be 300 miles to the next one that is open.

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You got that right,after dark it can be along way to a station that's open.

About the same as others have posted. My '16 2500 is listed as having a 31 gallon tank. I've ran it probably 20-30 miles after the low fuel light has come on and have never put more than 26 or so gallons in. I do look at the estimated "miles to empty" and go by that. It seems to be pretty conservative as it may say 30 miles to empty to start out, and after driving 15 miles it will still say 25 miles to empty (remember it's just a conservative estimate). I don't do this regularly, but on occasion. Have to admit a few times needing gas but driving the 30 miles home because the gas station next to me is a good bit cheaper.
A few other comments:
I know they say the tank is 31 gallons and only getting 26 gallons on a fill-up means 5 gallons left, but not confident it actually has 31 "useable" gallons. Have thought about putting a 5 gallon can in the back and driving until empty.
The "miles to empty" or "miles remaining" indicator has always worked pretty good on several vehicles. My wife almost always waits until the low fuel light comes on and goes by the miles remaining. We have gotten in her car to go someplace and the low fuel light is on, but she will say "oh, it shows we can go 22 miles before empty so we don't need gas yet........". Yes, it drives me crazy but she has never ran out of gas going by that, nor have she ever had fuel pump issues. She has had several vehicles that were bought new and had well over 100,000 miles on them with no issues.
Speaking of low fuel causing fuel pump to overheat and fail......if you ask me I will say this just doesn't happen. I've been a hobby mechanic for 30+ hours and worked in the automotive testing world for 12 years. There was never any concern in the automotive engineering world about premature wear on the fuel pumps from running low on fuel. They are designed to run this way because they know there are a lot of people like my wife that will run down to empty regularly. Having fluid pumps not submersed in fluid is quite common in many applications.

One thing i will say,is more fuel pumps are replaced in the summer,then winter,so heat does affect them,and running the tank constantly low,does usually put more heat into the pump.

2003F350 said:

Yours is REPEATABLE. They all are - they'll always come on at about the same time every time on the same vehicle. But they're far from ACCURATE, because on a truck identical to yours, that light will most likely come on at a different time.

Sorry, not trying to pick on anyone, it's just there's a difference between accurate and repeatable. Something can be 100% repeatable (always give the same reading) but not accurate (the reading could just be wrong). It can also be accurate but not repeatable (it'll be within +/- 5% of the correct reading, let's say, but every time it will read something different). Fuel pumps and low fuel warning lights are NOTORIOUS for being inaccurate but repeatable.

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No doubt. You are correct. I guess for my individual truck I look at it as being repeatably accurate as the truck repeatably takes 26 gallons of fuel if fueled very soon after the light comes on. Therefore, 6 gallons remain when the light comes on. Of course that is trusting that the fuel tank was in fact manufactured to hold 32 gallons of usable fuel. However, I have no plans to run it dry to find out! I will begin searching for decent fuel as soon as the light comes on. However, it is nice to know that I have a comfortable 100 mile cushion if needed. Of course if I am in an extremely remote area or for some reason fuel sources are far and few between I will not wait for a low fuel light and will take on fuel when appropriate for the situation.

For what its worth, ive ran my work truck (‘17 ram 1500) completely out of gas twice (fuel gauge wasnt working at the time). Dumped a can of gas in, started the truck and went on my merry way. Maybe the pumps ready to go now ?

On my 2017 1500, it comes on without fail exactly when the range left hits 50 miles. It's happened too many times now to be a coincidence. This has been when towing. Haven't run it that low with normal driving, though.

If you picture a Ram fuel tank, the bottom of the Fuel Fill Tube
Is Below the top of the Tank.
Where the bottom of the fill tube is located to the top of the Tank is for Air

32 gallon 4th Gen Ram



This image reminded me of another fuel related issue ...

IF you Over Fill your tank & fuel raises to the level that white fitting at the far Right.
Fuel can enter that section of tubing that runs toward the rear of the tank, IF fuel does enter that tube, it will go back to the Charcoal Cannister, that fuel degrades the Charcoal Pellets & at some time after that, your EVIC will tell you to visit the dealership

Jas34 said:

On my 2017 1500, it comes on without fail exactly when the range left hits 50 miles. It's happened too many times now to be a coincidence. This has been when towing. Haven't run it that low with normal driving, though.

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That’s how it is supposed to work. It calculates how many miles are left based on the current average mpg and comes on when that calculation is 50 miles. Get better mpg than what is displayed and you can go farther and vice versa.

I have only ever ran MY 19 to a fuel light once. I was on a trip going to Charlotte area from TX, and was in the Green Mtns, on IH 40, west, and a top tier station was no where to be found. I make it as a matter of practice, basically on a trip away from home to NEVA go below a 1/4 of a tank. I do the same thing with my MC. But then the gauge on my Honda Trike is almost dead on, and the thought of pushing an over 2,000 lb motorcycle down the road to a gas station sucks, lol.

Heck, here's a good one. My brand new Echo chain saw is a monster but also a PITA. When the fuel level gets low, it WILL not pick up, U have to put some more mixture in there. It is far more finicky than my STIHL. My Craftsman riding mower will run to the last drop, burp twice than be like a Ford, found on road dead, lmao.

ADDED: Back to RAM: It has been known for years the Fuel Gauges on trucks, RAM, because we R in a RAM Forum, but not held just to RAM. have incorrect fuel readings, leaning towards conservative than dead on. Nothing new, more like more nanny stuff to keep PPL from running out of gas, lol.

OLEJOE said:

That’s how it is supposed to work. It calculates how many miles are left based on the current average mpg and comes on when that calculation is 50 miles. Get better mpg than what is displayed and you can go farther and vice versa.

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YUP, wat the nanny computer does, ref EVIC MPG/MTE.

Unless you run the tank completely dry,your fuel pump is always submerged in fuel

This is because your pump is part of the fuel pump module,or bucket(in simple terms),that gets filled by a venturi system that will keep the bucket filled at any fuel level in the tank

Zoe Saldana said:

I need to know how many gallons are in the tank when the Fuel Warning Light comes on. I usually, don't go that low.

My 2500 has a 31 gallon tank and I vaguely remember in the past when the light went on I was able to put in 25+ gallons which would mean about 6 gallons or a bit more (because I took some time to get to the gas station).


What are your thoughts?

Thanks

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4 gallons

I wouldn’t know, because of the price of diesel I never let it get below half empty

Zoe Saldana said:

I need to know how many gallons are in the tank when the Fuel Warning Light comes on. I usually, don't go that low.

My 2500 has a 31 gallon tank and I vaguely remember in the past when the light went on I was able to put in 25+ gallons which would mean about 6 gallons or a bit more (because I took some time to get to the gas station).


What are your thoughts?

Thanks

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For my 2500, 5 gallons is about right. There are still a number of gallons left when miles to empty is 0.

2-4 gallons is common. With most. Some may have more. Also running fi vehicles low all the time will shorten the life of the fuel pump.

I try to fill up when I'm at about 1/8 of a tank. I was told a long time ago that you shouldn't let it run lower than 1/4 - 1/8 because it can lessen the life of your fuel pump. From reading above posts, sounds like that's no longer valid info.