Thoughts on Fuel Tank Capacity During a Long Drive...

[FinallyGotOne!]

Mine do it too, all the LC200s I have had do the same thing. You have about 4-6 gal left depending on how you typically fill your vehicle. Ie if you top off like I do and squeeze an extra gal or two in the tank then it would be perceivably that I had only 4 gal left when I fill up. If you quit at the first click, you might think you had 6 gal left....

This great point from a related thread made me wonder: Does anyone know - as the result of an actual (accidental?) "ran out of gas test" - how many gallons the fuel tank and filler neck can hold?

I routinely run up to 40 miles on the highway after the light comes on. If I know my average fuel economy, the number of miles I've driven since last fill up, and I assume I have at least 24.6 gallons or so of useable fuel, then I can easily calculate how many miles I can go after the light comes on. Like many of you, I have found that I can put in about 19.5 gallons after the light comes on if I allow the pump nozzle to shut off automatically and I stop there.

But! Do I have to fill the tank up to the top of the neck to get 24.6 gallons? I am betting that is not how the tank is designed. I'm betting we get about 24.6 gallons when the average nozzle shuts off.

I just returned from our twice yearly 28 hour trek up to PA and back, and I twice filled over two more gallons after the nozzle shut off. One time I got in 2.5 extra gallons, and the other I got in 2.7 gallons (and spilled a bit on the paint). You have to get a nozzle that allows you to slowly add gas; not all of them allow fine control of the pump speed.

Yesterday we had a strong headwind and I had a large bag on the roof, five adults and a large dog, guns, ammo, and suitcases - a full load. I could only average about 17.2 mpg. This might seem good, but two hours of that trip was at ~45 mph or less in snow and freezing rain. Anyway, after topping off the tank (2.5 gallons past auto-shut off) I drove about 387 miles, which was about 50 miles past when the low fuel light came on. I again filled the tank to the top of the neck with 22.7 gallons.

Here's what I wonder: If the truck holds 24.6 gallons at the top of the filler neck, that means yesterday I had only two gallons remaining...I don't know how much of that amount is useable, but certainly not more than a gallon if that. That's cutting it way too close.

My hypothesis: If the truck holds 27 gallons at the top of the filler neck, that could mean well over 100 miles of additional range after the low fuel light comes on, conservatively assuming 19.5 gallons have been burned at 18.5 average mpg and assuming we don't want to/can't use the last 1.5 gallons in the tank.

27-1.5-19.5=6 gallons available after light comes on; 6g*18.5mpg=111 miles! Or so...depending on how much risk you are willing to accept.

Is there a downside to filling up within a couple inches of the gas cap?

100 miles extra range at 75 mph! That's significant! Your thoughts?

 

[mark71]

Thought #1: After lift, tires, bumper, etc., I'm pretty convinced I am singlehandedly causing global warming. My highway MPGs are 13 at best.

Thought #2: There have been threads in the past about throwing codes when the charcoal canister is flooded with gas, possibly from over filling. I don't have much more info, so maybe someone else with more experience or better memory can chime in.

 

[gaijin]

I also have two thoughts:

1 - "Topping up" runs the real risk of overflowing gas into the charcoal canister and causing it to throw a code - not good. When I fill up, I just put in enough to reach the next even dollar amount after the nozzle automatically clicks off.

2 - The low fuel light comes on when there are approximately 4 gallons / 15 litres left in the tank. It makes no difference how much was in the tank when it was filled up. The idea (if I understand the OP correctly) that "topping up" the tank somehow buys more miles after the low fuel light comes on is ... incorrect.

HTH

 

[FinallyGotOne!]

The idea (if I understand the OP correctly) that "topping up" the tank somehow buys more miles after the low fuel light comes on is ... incorrect.
HTH

Agree...but it did get me wondering how much useable fuel I have depending on how soon I stop after first shut off. Thanks for the comments.

 

[Sandroad]

Based on the information below from my Owner's Manual, I'm sure the published tank capacity does not include the filler neck! And, based on this information, liquid gas in the filler neck is bad.


“Stop filling the tank after the fuel nozzle automatically clicks off.” and:
“Do not top off the tank.”


“Doing so may damage the vehicle, such as causing the emission control systems to operate abnormally or damaging the fuel system components……”

 

[Markuson]

This great point from a related thread made me wonder: Does anyone know - as the result of an actual (accidental?) "ran out of gas test" - how many gallons the fuel tank and filler neck can hold?

I routinely run up to 40 miles on the highway after the light comes on. If I know my average fuel economy, the number of miles I've driven since last fill up, and I assume I have at least 24.6 gallons or so of useable fuel, then I can easily calculate how many miles I can go after the light comes on. Like many of you, I have found that I can put in about 19.5 gallons after the light comes on if I allow the pump nozzle to shut off automatically and I stop there.

But! Do I have to fill the tank up to the top of the neck to get 24.6 gallons? I am betting that is not how the tank is designed. I'm betting we get about 24.6 gallons when the average nozzle shuts off.

I just returned from our twice yearly 28 hour trek up to PA and back, and I twice filled over two more gallons after the nozzle shut off. One time I got in 2.5 extra gallons, and the other I got in 2.7 gallons (and spilled a bit on the paint). You have to get a nozzle that allows you to slowly add gas; not all of them allow fine control of the pump speed.

Yesterday we had a strong headwind and I had a large bag on the roof, five adults and a large dog, guns, ammo, and suitcases - a full load. I could only average about 17.2 mpg. This might seem good, but two hours of that trip was at ~45 mph or less in snow and freezing rain. Anyway, after topping off the tank (2.5 gallons past auto-shut off) I drove about 387 miles, which was about 50 miles past when the low fuel light came on. I again filled the tank to the top of the neck with 22.7 gallons.

Here's what I wonder: If the truck holds 24.6 gallons at the top of the filler neck, that means yesterday I had only two gallons remaining...I don't know how much of that amount is useable, but certainly not more than a gallon if that. That's cutting it way too close.

My hypothesis: If the truck holds 27 gallons at the top of the filler neck, that could mean well over 100 miles of additional range after the low fuel light comes on, conservatively assuming 19.5 gallons have been burned at 18.5 average mpg and assuming we don't want to/can't use the last 1.5 gallons in the tank.

27-1.5-19.5=6 gallons available after light comes on; 6g*18.5mpg=111 miles! Or so...depending on how much risk you are willing to accept.

Is there a downside to filling up within a couple inches of the gas cap?

100 miles extra range at 75 mph! That's significant! Your thoughts?

Yesterday I pumped 25.3 gallons in...so I came darn close...

 

[Chocolate]

I think 17.2 mpg is good for this platform... I get 12 mpg consistently on mostly highway.

 

[Island1064]

Seems Long ranger has come with a Tank for the V8 cruiser with a carbon canister http://thelongranger.com.au/toyota/landcruiser/200-series/ta65mp

I so want one of these.

 

[TeCKis300]

Time to learn some things boys. As you will understand that topping off gas into the filler neck is a bad idea.

1) All modern gas tanks have some designed in space to allow for some fuel expansion. As the car is operated, with the exhaust heat, fuel pump heat, and environment warming up, fuel will expand. Perhaps you've filled the gas tank on a cold morning and now it is sitting completely full in the hot sun... If you've topped off the tank to take all the void space, guess where it might go?
2) In the US, all modern cars have charcoal canisters. It's designed to trap fuel vapor so that it doesn't vent to the atmosphere. When running, this vapor is released into the intake manifold and burned off. If you've topped off the tank, you are surely taxing the the charcoal canister more. Now if you've aggressively topped off the tank on a cold morning, and perhaps let it sit in the sun, there's a very real chance that liquid fuel may get into the charcoal canister. Charcoal canisters are expensive to change. And you will not pass smog with a failed canister (in CA at least) due to CEL.
3) The lost extra fuel and fuel vapor will be burned off/lost in a way that doesn't contribute to mpg.

I personally don't top off my cars. But I'd imagine lightly topping it off would be fine.

You guys don't have to believe me on this . There's plenty of information and anecdotal advice on the internet, and changing of charcoal canisters because of this.

That said, I don't like how conservative the range to empty readout is. And I'm interested in that long ranger tank!

 

[Markuson]

Time to learn some things boys. As you will understand that topping off gas into the filler neck is a bad idea.

1) All modern gas tanks have some designed in space to allow for some fuel expansion. As the car is operated, with the exhaust heat, fuel pump heat, and environment warming up, fuel will expand. Perhaps you've filled the gas tank on a cold morning and now it is sitting completely full in the hot sun... If you've topped off the tank to take all the void space, guess where it might go?
2) In the US, all modern cars have charcoal canisters. It's designed to trap fuel vapor so that it doesn't vent to the atmosphere. When running, this vapor is released into the intake manifold and burned off. If you've topped off the tank, you are surely taxing the the charcoal canister more. Now if you've aggressively topped off the tank on a cold morning, and perhaps let it sit in the sun, there's a very real chance that liquid fuel may get into the charcoal canister. Charcoal canisters are expensive to change. And you will not pass smog with a failed canister (in CA at least) due to CEL.
3) The lost extra fuel and fuel vapor will be burned off/lost in a way that doesn't contribute to mpg.

I personally don't top off my cars. But I'd imagine lightly topping it off would be fine.

You guys don't have to believe me on this . There's plenty of information and anecdotal advice on the internet, and changing of charcoal canisters because of this.

That said, I don't like how conservative the range to empty readout is. And I'm interested in that long ranger tank!

I don't claim you are wrong about how the system works, because I frankly don't know diddly about that aspect.
But what I do know is that I've been topping off Land Cruisers (100 and 200) for 15+ years and have never had a problem with the fuel system. Maybe I'm doing it wrong?

Curious about this.

Doesn't the shape of the main tank create its own air space on the top/front for expansion? I seem to recall its shape goes upward, which would trap air in there just about no matter what. Not at all certain... Someone can educate me I'm sure.

 

[Romer]

Seems Long ranger has come with a Tank for the V8 cruiser with a carbon canister http://thelongranger.com.au/toyota/landcruiser/200-series/ta65mp

I so want one of these.

I checked into that. The carbon canister is for the Aussie laws. It doesnt really replace the one for the main tank and you still have all the hookup connection issues. Slee said they wouldnt install it for me as there are just to many issues

 

[Island1064]

I checked into that. The carbon canister is for the Aussie laws. It doesnt really replace the one for the main tank and you still have all the hookup connection issues. Slee said they wouldnt install it for me as there are just to many issues

Darn. Help us Obi Wan Slee, you are our only hope !

I would not care if I needed to fill the second tank separately, just need a transfer pump. Would give a lot for an extra 20 Gallons worth of range.

 

[Markuson]

Darn. Help us Obi Wan Slee, you are our only hope !
I would not care if I needed to fill the second tank separately, just need a transfer pump. Would give a lot for an extra 20 Gallons worth of range.

Me too. This has been coming up for years. There was one guy who posted about his process for fitment. It was a royal pain, and I doubt it would even be legal where I live (Kalifornistan). I finally concluded that 3 jerry cans on Slee's upcoming bumper will have to do...

 

[Island1064]

Yep I remember that one 47 Gallon Long Ranger Aux Tank installation USA 200 series...

I've seen some tanks that attaches to the spare wheel brackets on the back of Jeeps, are these worth something?

Can't remember the name.

 

[Romer]

The one your thinking of is a Titan Fuel Trekker

There is also one that goes in the spare tire location on the underside of a chevy. Looks like a similar stock setup, not sure if it would fit . Here is that link

 

[Island1064]

Thanks, that is exactly what I was thinking.

 

[Taco2Cruiser]

Time to learn some things boys. As you will understand that topping off gas into the filler neck is a bad idea.

1) All modern gas tanks have some designed in space to allow for some fuel expansion. As the car is operated, with the exhaust heat, fuel pump heat, and environment warming up, fuel will expand. Perhaps you've filled the gas tank on a cold morning and now it is sitting completely full in the hot sun... If you've topped off the tank to take all the void space, guess where it might go?
2) In the US, all modern cars have charcoal canisters. It's designed to trap fuel vapor so that it doesn't vent to the atmosphere. When running, this vapor is released into the intake manifold and burned off. If you've topped off the tank, you are surely taxing the the charcoal canister more. Now if you've aggressively topped off the tank on a cold morning, and perhaps let it sit in the sun, there's a very real chance that liquid fuel may get into the charcoal canister. Charcoal canisters are expensive to change. And you will not pass smog with a failed canister (in CA at least) due to CEL.
3) The lost extra fuel and fuel vapor will be burned off/lost in a way that doesn't contribute to mpg.

I personally don't top off my cars. But I'd imagine lightly topping it off would be fine.

You guys don't have to believe me on this . There's plenty of information and anecdotal advice on the internet, and changing of charcoal canisters because of this.

That said, I don't like how conservative the range to empty readout is. And I'm interested in that long ranger tank!

Yea I agree with your points, I never topoff either, for environmental reasons, but as far as expansion, the stock tank can't be over filled by the baffle design. There are pockets in the top, that are located higher than the fill neck, so physics alone, you can't overfill a modern tank. Plus the charcoal canister in the back of the truck is also higher than the tank, runs through a j curve fitting into the fuel pump inner bucket. So physics again, fuel isn't getting into those components unless you fill the tank and tilt the truck over 45 degrees on its side. I found these things out on modern tanks from building auxiliary fuel cells, engineers don't trust buyer, so these stop gaps exist. The worst that will happen from overfilling a tank is spilling on the ground and side of your truck, which is why I stop pumping when the auto pump clicks.

 

[Markuson]

Yea I agree with your points, I never topoff either, for environmental reasons, but as far as expansion, the stock tank can't be over filled by the baffle design. There are pockets in the top, that are located higher than the fill neck, so physics alone, you can't overfill a modern tank. Plus the charcoal canister in the back of the truck is also higher than the tank, runs through a j curve fitting into the fuel pump inner bucket. So physics again, fuel isn't getting into those components unless you fill the tank and tilt the truck over 45 degrees on its side. I found these things out on modern tanks from building auxiliary fuel cells, engineers don't trust buyer, so these stop gaps exist. The worst that will happen from overfilling a tank is spilling on the ground and side of your truck, which is why I stop pumping when the auto pump clicks.

I agree spilling isn't good. But... I can get nearly 2 full gallons in after the pump shut-off & I've never spilled. Last night I put in 25.3. Not sure how much more I could have squeezed...

 

[i4c4lo]

From experience - granted it was on an 80 Series and 100 Series that filling it all the way to the top is not a good idea. TeCKis300 is right with the charcoal canister going bad. The charcoal canister on an 80 is bad in terms of price, the 100 Series is even more so. I don't want to know how much it will be for the 200 Series.

I had A LOT of issues on my 100 with the LRA tank and gas vapor ONLY at altitude and off-road. The gas vapor is overwhelming to a point that I have to get my family out and vent the gas tank(s).

I had a similar issue with my LX570 over the summer at the White Mountains - off-road, about 10,000 feet and 80F+. It sounds like the gas is boiling - I will upload a video in youtube and will reference it to this thread. Maybe the heat and all that sloshing around? Not sure. It was a good time to stop and take photos anyway. I just drove around with the gas cap partly open to keep venting as we drove to higher altitude. No CEL - once we got back down to Bishop I closed the cap all the way.

A 2nd tank of the 200/LX would be great. I've thought about buying the LRA from AUS and just making a bracket to drop the gas tank itself to clear the charcoal canister. I think something else will hit before the tank drags or hits. Then have a stand alone aftermarket charcoal canister for the secondary tank to vent and not overwhelm the stock charcoal canister.

Happy New Year gentlemen.

 

[kreiten]

Yea I agree with your points, I never topoff either, for environmental reasons, but as far as expansion, the stock tank can't be over filled by the baffle design. There are pockets in the top, that are located higher than the fill neck, so physics alone, you can't overfill a modern tank. Plus the charcoal canister in the back of the truck is also higher than the tank, runs through a j curve fitting into the fuel pump inner bucket. So physics again, fuel isn't getting into those components unless you fill the tank and tilt the truck over 45 degrees on its side. I found these things out on modern tanks from building auxiliary fuel cells, engineers don't trust buyer, so these stop gaps exist. The worst that will happen from overfilling a tank is spilling on the ground and side of your truck, which is why I stop pumping when the auto pump clicks.

I don't think this had anything to do with overfilling our tanks, as I was one of the trucks that had this issue and never overfill my tank. But as we drove through the hot sun in Moab and our trucks shook around the expansion in our tanks was more than the system could handle. We had gas spraying out of the gas cap. you could actually hear the pressure whistling out of the cap prior to even removing it. Part of our look as we rolled through Moab was gas streaks down the side of our rigs. I'm guessing the system just could not alleviate the amount of pressure that was building due to heat and shaking? @Taco2Cruiser what's your best guess on this?