Gas tank fuel capacity.

[Johnnycakes]

I was tricked by the title of the thread so I’ll ask what I thought I’d find...

what is the true fuel capacity(gallons) of my 16 LR4?

My low fuel light will turn on, I’ll drive for another 10-20 miles, fill up, and I can only get 18 or so gallons in!

 

[DaytonaRS7]

I was tricked by the title of the thread so I’ll ask what I thought I’d find...

what is the true fuel capacity(gallons) of my 16 LR4?

My low fuel light will turn on, I’ll drive for another 10-20 miles, fill up, and I can only get 18 or so gallons in!

22.8 gallons actual capacity.
*removed*

EDIT: see post below for actual reserve capacity

 

[gsxr]

Fuel trim percentages may vary with altitude, possibly more so with normally aspirated engines (V8, not SCV6). Numbers at sea level may be different than at higher elevations. 1-3% seems stupid low to me and totally normal. I'd be more concerned if the numbers were double digits, or drastically different between banks.

The reserve light on USA models turns on when there is ~12 liters / ~3.0 gallons of fuel remaining in the tank (approx 19.8 gallons consumed, of 22.8 gallons total capacity - see details below). This triggers the "miles remaining" display in the cluster, which counts down to zero, and zero means zero, with a small margin of error. When it counts to zero, it doesn't mean there's 3+ gallons left. Don't ask how I know this.

There is a slight conflict between specs in the factory service manual (FSM) and owner's manual. The FSM says 86.3L total fuel tank capacity, which matches the OM data. But a few pages later the FSM says "86.0 L (19.0 gallon) usable capacity", which is inaccurate (86L = 22.7 gal, not 19.0!). The USA OM says 86.3L (22.8 gallon) capacity, in the Maintenance section, page 194.

Also, the FSM says 10 liter / 2.8 gal reserve, but in the USA OM Fuel & Refueling section, page 165, it says "When the remaining fuel reaches a minimum of 12 liters (3.0 gallons), the amber low fuel warning indicator illuminates. The remaining fuel should give a range of approximately 50 miles."

Again, their numbers are a bit off, 12 liters is ~3.2 gallons (not 3.0), but you get the idea. The discrepancy might be due to software differences between USA models, and non-USA models. Maybe 10 liter reserve is for non-USA models?

I routinely run 20-30 miles beyond the reserve warning (generally around 300 miles) and typically put in 19-21 gallons at fillup. I've also found the claimed MPG on the cluster is high by a solid 7-10% despite using the GAP IID tool to adjust it, and it's at the limit of adjustment. I calculate MPG based on the trip odometer and gallons filled, since the computer reading is optimistic.

 

[avslash]

Actually, I found myself stranded 2 miles outside of Amarillo Texas one time when my DTE calculator showed 24 miles left.

Trust that thing at your own peril.

 

[gsxr]

Actually, I found myself stranded 2 miles outside of Amarillo Texas one time when my DTE calculator showed 24 miles left.

Trust that thing at your own peril.

I don't trust the "miles remaining" at all, partly because it doesn't start a countdown until the reserve light illuminates. AND, I don't trust the reserve light either. After I ran out of gas one time (thankfully, within sight of a gas station) I started watching these like a hawk. I found the reserve light triggers with different amounts of fuel remaining almost every tank. I don't know if it's a faulty sending unit, faulty software, or both.

I watch the trip odometer instead. I know roughly when the reserve light should turn on, based on the trip odo. Any time the two seem to conflict, I go by the odometer and fill up early.

Both the fuel level sensor and oil level sensor are total crap on an otherwise solid truck. We need a dipstick for both the engine sump and the fuel tank? Sad.

 

[Jimmy Brooks]

Not sure if my car was up to operating temperatures. I’m not home now, but when I am I’ll go for a longer drive and check both long term and short term fuel. I’d be surprised if it’s driving style because for years 2 years when I was driving it, it would read over 300 miles on a full tank. Plus for it to drop almost 1/3 of its original capacity is a lot. I think it’s possible it could be the trip computer. But in order to find out accurately I’ll have to track it with the odometer.

 

[Michael Gain]

Yes, because the measured ratio is lean. The ecu then adds fuel to make up for the difference between the observed ratio and optimal--hence, the positive addition of fuel.

Isn’t a positive % a richer mixture? I for the most part don’t think I have anything to worry about with my fuel trims. I’m just surprised it’s close to 0. The ambient temp has been 100-105 every day recently.

 

[ktm525]

This is the one of the drawbacks to the LR4. The tank size makes sense for the diesels but for a 5.0L gas engine it is way to small. It should be 50% larger.

 

[Jimmy Brooks]

Reset the trip computer today filled up with gas and boom 302 miles. I clocked the mileage and so far I’ve gone through 21 miles of gas and driven 20 miles. I was idling in place for a while so that’s probably where the 1 mile escaped. I’ll keep you guys posted, thanks for all the help! Here is a picture for my short term and long term fuel trims at idle at operating temperatures.

 

[Coffee]

This is the one of the drawbacks to the LR4. The tank size makes sense for the diesels but for a 5.0L gas engine it is way to small. It should be 50% larger.

Abso-f’ing-lutely.

I drove my F-150 for five years, and then when my oldest kid was finally old enough to drive himself to practice and work, I bought a 2013 LR4 to drive. I love the LR, but man I miss that 36 gallon extended range fuel tank.

Now I fill up the tank so often that I’ve moved the GasBuddy app to the first page of my iPhone.