Help: How much gas does your tank let you fill?

[paulr]

I don’t know for sure. I just know when my range gets to lo miles I can put around 16.5-17 gallons in the tank. If it’s 21.5 them simple math tells me it’s 4.5 gallons. I’ve been tempted to run it dry to see if there is really that much gas left in the tank but it’s simply too dangerous to do.

I can almost guarantee you don’t have 4.5 left at that point. You’re probably just not able to top off the tank fully. Why is it so dangerous to test out if you really want to know?

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[chadly25]

I don't have access to private roads to run the tank dry. Would hate to run out of gas in traffic.

 

[Rubi-Zero]

I normally just fill up until it first clicks off, and that is normally around 17-18 gallons, but today after running my tank Very low to where it read 10 gallons, I filled up like I normally would, then pulled the pump slightly out and very slowly pumped more fuel into the tank. It stoped at 20 gallons.

 

[paulr]

I don't have access to private roads to run the tank dry. Would hate to run out of gas in traffic.

when I ran this little experiment I just stayed in my neighborhood and did like a 1 mile-ish loop, never on main streets, etc. It was a pain and took forever but got the answer to the question I was trying to solve and was able to safely pull over and not on any major streets or anything and then just filled in the 1 gallon reserve tank I had taken with me.

 

[47Jeepster]

The gas gauge on our jeeps is not the most accurate device in the Jeep. And, since the tank is long and narrow that probably contributes to fuzzy readings. To alleviate some of this inaccuracy, I recorded the gallons to fill the tank and the gas gauge reading for 15 fill-ups and then plotted the data. Three fill-ups took place after driving a number of miles past the gauge reading empty and aren't shown on the chart ... 19.35 gallons was the most fuel I added to the tank. I have a 4-door Rubicon and the fill-ups occurred in Arizona and California.

I tried to drive on a straight and level road for a mile or so to obtain the most accurate gauge reading before filling up the tank. I would do a normal auto fill-up, record the gallons, and then pull the nozzle out until only the straight part was in the fill tube, center the nozzle in the fill tube, and then, do a second auto fill. The difference between the standard auto fill and the handheld auto fill averaged 0.2 gallons and ranged from 0.1 to 0.4 gallons ... quite a bit of inaccuracy it you only use the standard auto-fill.

The plotted data shows that between full and empty the gauge responds in a very linear manner ... the tread-line showed an R2 factor of 0.997 which is quite good. Lots of judgement involved in deciding when the gauge reads full and when it reads empty.

The accuracy of the "low fuel light" is suspect. I only obtained two data points, but they show a difference of 0.65 gallons ... not an indicator you should feel comfortable depending upon. The plot shows the 4.8 gallon average. The 4.5 gallon data point occurred while driving straight down a level road. The 5.1 gallon data point occurred while cornering hard. Since others have reported 4.5 gallons for the "low fuel light" coming on, I'll use that value in the summary.

Summary:

The bottom line, for my Jeep, is that when the tank is filled, I need to burn approximately 1.0 gallon of fuel before the needle will come off full. When the "low fuel light" comes on, I have approximately 4.5 gallons of fuel left in the tank. And, when the needle hits empty, I have 3.0 gallons of fuel left in the tank. I'll trust the FCA reported value of 1.0 gallon of unusable fuel left in the tank when the engine stops running.

As always, YMMV ...

 

[Swanny297]

I have a trail dash that displays fuel % - not sure how accurate it is but when my tank is full and I can’t get any more in it reads 93-95% never had it go above 95%.

 

[47Jeepster]

I have a trail dash that displays fuel % - not sure how accurate it is but when my tank is full and I can’t get any more in it reads 93-95% never had it go above 95%.

The trail dash hooks into the Jeep electronics, and thus, into the fuel measuring system ... yes? If so then it's probably noting that the in-tank float is at it's maximum height. Your remaining 5-7% equates to (0.05 * 21.5 gal = 1.1gal) 1.1 to 1.5 gallons in the tank that can't/doesn't raise the float any higher. That means you have to burn off 1.1 to 1.5 gallons of fuel before the trail dash numbers start reduce ... sounds like what I measured ... yes?

What is the lowest percent that your trail dash will register? Suspect that it hangs up at about 12 to 14% and doesn't go any/much lower. Yes?

 

[spurly]

There is obviously an issue if you're only able to fill up 16 gallons. But you will probably never be able to run the tank completely dry, even after driving 20-30 miles after Low Miles comes on, thus always leaving 1-2 gallons in the tank only allowing you to fill up 19-20 gallons max.

Take a pitcher of water and dump it in your bathtub. Now shake your bath tub (if it were possible) any sort of pump you had in the tank even if it were sitting on the bottom would not be able to pump out the last remaining gallon.

 

[Swanny297]

The trail dash hooks into the Jeep electronics, and thus, into the fuel measuring system ... yes? If so then it's probably noting that the in-tank float is at it's maximum height. Your remaining 5-7% equates to (0.05 * 21.5 gal = 1.1gal) 1.1 to 1.5 gallons in the tank that can't/doesn't raise the float any higher. That means you have to burn off 1.1 to 1.5 gallons of fuel before the trail dash numbers start reduce ... sounds like what I measured ... yes?

What is the lowest percent that your trail dash will register? Suspect that it hangs up at about 12 to 14% and doesn't go any/much lower. Yes?

I have been down to 7% (I think) and my fuel light was on.

 

[YYCSahara]

From my experience with Toyota trucks it's the same way with Tacomas and Tundras.

Tundra has a 38 gal tank and when fuel light comes on (about 30mile to Empty as per comp) people have only been able to pump 30-31 gal. 8 gal "reserve" is huge.

Another thing about fuel pumps is that they don't get cooled by fuel around them, but fuel flowing through them, so that's why you don't see fuel pumps burning out all the time anymore.

 

[jbkJL]

I have a similar issue with the 2018 Jeep JLRU 2.0L only letting us fill up with 16-17 gallons and meter says its just below full. We had to have the evap canister and a valve replaced already and now the Jeep is back in the shop with the engine light on and similar problem agian. Dealer told us we were filling it up too much the first time. We usually let the pump run until it automatically shuts off, Then we do not try to add any more fuel. Yesterday the Jeep was actually leaking fuel out of the rear passenger side right next to the muffler. This is now a safety issue that i am concerned with and will be filing a case with NHTSA. Engine has tried to stall a couple of times or runs rough. We have had a very strong gas smell as well with no leaks after a previous fill up. Nothing like walking out into the garage and then being greeted with a strong smell of gas being created by your Jeep with less than 9000 miles on it.

 

[Jaredhoefsmit]

I have a similar issue with the 2018 Jeep JLRU 2.0L only letting us fill up with 16-17 gallons and meter says its just below full. We had to have the evap canister and a valve replaced already and now the Jeep is back in the shop with the engine light on and similar problem agian. Dealer told us we were filling it up too much the first time. We usually let the pump run until it automatically shuts off, Then we do not try to add any more fuel. Yesterday the Jeep was actually leaking fuel out of the rear passenger side right next to the muffler. This is now a safety issue that i am concerned with and will be filing a case with NHTSA. Engine has tried to stall a couple of times or runs rough. We have had a very strong gas smell as well with no leaks after a previous fill up. Nothing like walking out into the garage and then being greeted with a strong smell of gas being created by your Jeep with less than 9000 miles on it.

Happened to me on my first JL. Gas leaked all over and only would fill 7/8 of a tank. Dealer bought it back (day 2 of ownership when it puked gas)

 

[JeepCares]

I have a similar issue with the 2018 Jeep JLRU 2.0L only letting us fill up with 16-17 gallons and meter says its just below full. We had to have the evap canister and a valve replaced already and now the Jeep is back in the shop with the engine light on and similar problem agian. Dealer told us we were filling it up too much the first time. We usually let the pump run until it automatically shuts off, Then we do not try to add any more fuel. Yesterday the Jeep was actually leaking fuel out of the rear passenger side right next to the muffler. This is now a safety issue that i am concerned with and will be filing a case with NHTSA. Engine has tried to stall a couple of times or runs rough. We have had a very strong gas smell as well with no leaks after a previous fill up. Nothing like walking out into the garage and then being greeted with a strong smell of gas being created by your Jeep with less than 9000 miles on it.

Hi jbkJL,
We're truly sorry to hear about this. We'd like to take the opportunity to have this concern escalated to a Case Specialist in order to have this looked into further. Please send us a private message at your earliest convenience.
Lydia
Jeep Social Care Specialist

 

[jl73660]

Just fill it up and go !

 

[Strommen95]

The JK was the exact same way.. Mine was a 22.5 gallon tank, I’d always fill up between 17-18 gallons as soon as the light came on. The worst I ever pushed it to was 20.5 gallons. Nothing is wrong, it’s by design. I’ve had my JLU for a shorter time, but the few times I’ve ran it to the gas light filling up was about 17 gallons(tank is 21.5 now.) Honestly this is making an issue out of nothing.

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