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First long trip review + gas mileage/gas tank rant

Kevin_D

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i guess that depends on where for sure
I drove north out of San Diego one Sunday morning, and I was being passed by at least ½ of the traffic...
And I was doing 80!

But back to the topic at hand.

Kevin
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ShadowsPapa

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I drove north out of San Diego one Sunday morning, and I was being passed by at least ½ of the traffic...
And I was doing 80!

But back to the topic at hand.

Kevin
Yeah, the bloody gas tank. OK, so it's a 22 gallon tank, at least let us get 22 gallons in it!
This bit about not getting more than 18.5 in unless you stand there for several minutes barely trickling gas in until you finally get 20-21 in the thing is weird.
They need to call it a 20 gallon tank. That's about all you can get in even when it's nearly dry.

There, does that fix the thread?
 

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Jeep Gladiator First long trip review + gas mileage/gas tank rant D64B3307-B111-44FD-9E1C-F36C16CC77F5
bought the Mojave last Friday - 2200 miles later. 16 mpg average. All highway miles. I did put 35 / 11.5 on brand new. I put 50k a year on a truck - we will see what she does.
 

Oil_Burner

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Yeah, the bloody gas tank. OK, so it's a 22 gallon tank, at least let us get 22 gallons in it!
This bit about not getting more than 18.5 in unless you stand there for several minutes barely trickling gas in until you finally get 20-21 in the thing is weird.
They need to call it a 20 gallon tank. That's about all you can get in even when it's nearly dry.

There, does that fix the thread?
They (manufacturer and EPA) don't want you to totally fill your tank because of emissions of gasoline and/or gasoline vapors from the vehicle. They must leave room for expansion of gasoline. Why? When you fill your vehicle with cold fuel from underground storage tanks, and that fuel expands due to the high ambient temperatures outside. The vapors need to go somewhere. The evaporative emissions system is designed to capture the vapors before those vapors reach the environment. When the tank is full of liquid, and that liquid expands into the container, that liquid gasoline reduces/destroys the ability of the evaporative emission system to function.

Although not apples to apples because it doesn't have an evaporative emission system, but I've filled my diesel pusher with a 90 gallon tank "too much" where I milked in as much as I could, took it 1 mile and parked it. Two days later I noticed that the vent had been leaking fuel on the garage floor. I put a container under it and captured another quart. Now I only fill it as much as possible if I'm gong to keep driving, and not parking it.

I'm not complaining about tank size myself... yet. My first tank got me 464.5 miles at 29.5 MPG per the computer, almost all highway driving, with some tailwinds.

It's been some years, but I recall the data label on the motorhome tank stating something like it should not be filled more than 90% of it's total capacity. If this is true for all motor vehicle tanks, your 22 gallon tank is likely designed to only fill to 19.8 gallons of gasoline and 2.2 gallons of vapor space.
 
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danielspivey

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Not exactly apples to apples, but out stock Sport S with the 3.73 gears will give us about 26 mpg on a long freeway drive, such as San Jose to San Diego and back.
Your tire diameter must have been accidentally inputted as 24” from the dealer....
 

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ShadowsPapa

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They (manufacturer and EPA) don't want you to totally fill your tank because of emissions of gasoline and/or gasoline vapors from the vehicle. They must leave room for expansion of gasoline. Why? When you fill your vehicle with cold fuel from underground storage tanks, and that fuel expands due to the high ambient temperatures outside. The vapors need to go somewhere. The evaporative emissions system is designed to capture the vapors before those vapors reach the environment. When the tank is full of liquid, and that liquid expands into the container, that liquid gasoline reduces/destroys the ability of the evaporative emission system to function.

Although not apples to apples because it doesn't have an evaporative emission system, but I've filled my diesel pusher with a 90 gallon tank "too much" where I milked in as much as I could, took it 1 mile and parked it. Two days later I noticed that the vent had been leaking fuel on the garage floor. I put a container under it and captured another quart. Now I only fill it as much as possible if I'm gong to keep driving, and not parking it.

I'm not complaining about tank size myself... yet. My first tank got me 464.5 miles at 29.5 MPG per the computer, almost all highway driving, with some tailwinds.

It's been some years, but I recall the data label on the motorhome tank stating something like it should not be filled more than 90% of it's total capacity. If this is true for all motor vehicle tanks, your 22 gallon tank is likely designed to only fill to 19.8 gallons of gasoline and 2.2 gallons of vapor space.
Sorry, you missed the point, (and the fact I'm a decades long mechanic myself) as I am well aware of fuel expansion, having had multiple 500 gallon gas and diesel tanks on my farm when I farmed years ago. I have removed, repaired, cleaned, replaced, whatever, many dozens of auto and truck gas tanks.
I keep several large containers of gas around because of the equipment I have and we live a ways from fuel - and know you stop at the line or have gas on the floor on a hot day. I also know not to fill my classic cars beyond the states owner manual capacity or I'll have gas dripping at the rear center fill tube.

There are ways to design tanks to have 22 gallon capacity and have room for expansion. Every vehicle we've ever owned, Ford, GM/Chevy, even prior Jeeps, when the tank was virtually empty - you could get within tenths of a gallon of the capacity back in it (assuming the last 8 tenths were still there or you'd be on the road stopped out of fuel.)

My wife's Jeep - when she runs it down to 20 miles left, you can get all but full capacity in it. My Silverado was the same way.
This is the first truck that stops you at 18.5 when the capacity is 22 and you are down to 15 miles left.
I ran my wife's Grand Cherokee down to where she was giving me warnings like "if you run us out....." (and I knew I'd be in trouble) a few weeks ago and got within a half gallon of capacity in it without standing there milking the nozzle. She asked how much I got in it - and it was all but tank capacity. I had only pulled the trigger one time after it shut off the first time.

Can't do that with the JT.
They could leave head space in these and still allow 22 gallons of gas in them. All of our other Jeeps did.
This is a design issue with the JT. Look at those complaining that it kicks back at them, or other issues. I've never had so much trouble with anything I have ever owned or worked on getting fuel into it. If you stop where it kicks off - the gauge won't even read full on mine. That should say something.
They are advertising useful capacity on every other vehicle - if it says 24 (like another Jeep did) you could get 24 in it if empty and not squeeze hard. You could do 23 if it said "20 miles" for the range. Not the JT. They advertise 22 but you may get 19 in on a good day. IF you really really try yo can get more in.
Design issue. (poor design)
 

Oil_Burner

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Can't do that with the JT.
They could leave head space in these and still allow 22 gallons of gas in them. All of our other Jeeps did.
This is a design issue with the JT. Look at those complaining that it kicks back at them, or other issues. I've never had so much trouble with anything I have ever owned or worked on getting fuel into it. If you stop where it kicks off - the gauge won't even read full on mine. That should say something.
They are advertising useful capacity on every other vehicle - if it says 24 (like another Jeep did) you could get 24 in it if empty and not squeeze hard. You could do 23 if it said "20 miles" for the range. Not the JT. They advertise 22 but you may get 19 in on a good day. IF you really really try yo can get more in.
Design issue. (poor design)
It must be that the last several vehicles, Ford, Chevy, Toyota, that I've owned have had the same issue with getting full capacity into a tank that the JT has. I usually could only stuff in somewhere between 1 and 2 gallons less than the the tank capacity. I was assuming, possibly incorrectly, that the inability to fill to published capacity when nearly empty was by design, to allow for expansion.

You showed a picture of a pump pickup in a tank several posts back. I've only been inside a couple of tanks. One interesting one was my wife's 1987 Dodge Daytona 2.2L Turbo. It had an in-tank fuel pump, which sat inside a setup that utilized the return fuel to suck the tank fuel into the area where the fuel pump was located. It's been a long time ago, but from what I could tell, it appears to spin the fuel inside that area so even when the tank was low, the level in that setup caused the fuel spinning, to remain higher, allowing the pump to get nearly all the fuel out of the tank. If I recall correctly, that vehicle could be run nearly to empty and fill to the published capacity.
 
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ShadowsPapa

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It must be that the last several vehicles, Ford, Chevy, Toyota, that I've owned have had the same issue with getting full capacity into a tank that the JT has. I usually could only stuff in somewhere between 1 and 2 gallons less than the the tank capacity. I was assuming, possibly incorrectly, that the inability to fill to published capacity when nearly empty was by design, to allow for expansion.

You showed a picture of a pump pickup in a tank several posts back. I've only been inside a couple of tanks. One interesting one was my wife's 1987 Dodge Daytona 2.2L Turbo. It had an in-tank fuel pump, which sat inside a setup that utilized the return fuel to suck the tank fuel into the area where the fuel pump was located. It's been a long time ago, but from what I could tell, it appears to spin the fuel inside that area so even when the tank was low, the level in that setup caused the fuel spinning, to remain higher, allowing the pump to get nearly all the fuel out of the tank. If I recall correctly, that vehicle could be run nearly to empty and fill to the published capacity.
The tank I showed was my SX4 tank - I put an in-tank Jeep electric pump in it to supply my 4.0 engine conversion. Didn't want to hack the tank up as it was nearly perfect inside and out.
The issue with the way I did it - if you get under 1/4 tank you had better not take corners really fast or nail it going up a hill - the engine will "hiccup" as the pressure drops momentarily. Different vehicles, different tanks, have different ways of handling that. The ZJ had a "module" in the top of the tank that prevented that sloshing away from the electric pump pickup but the sending unit float itself was outside of that module. I had thought of modifying my SX4 system by surrounding the pump with some sort of a "can" and directing the return into that can and having a given number and size of holes in the bottom of the can to let fuel in, but not let it get out fast. I was going to study other EFI vehicle tanks - but I figured why, when I just don't let that SX4 get that low. I get good economy with it and don't drive it on cross-country trips so no big deal. I treat it like a 16 gallon tank.
One reason I'm so "aware" of what we can get in our vehicle tanks, the size of the tanks, and how low we let them get is that the local grocery store chain - which also sells fuel, has convenience stores and so on - has a "perks" card thing. You buy groceries and certain items earn you points and now and then buying x dollars worth of groceries earns you points. Those points translate to pennies. 32 points is 32 cents (which we have now) - that number is then the discount you get on fuel up to 20 gallons. So if you have earned 100 points, that's a buck a gallon off up to 20 gallons. Trust me, I hate giving anything back to then so I try to make sure we can get 20 gallons in a vehicle when I want to fill and use those "fuel saver" points. They partnered with Casey's General Stores here, too so I can even go to Casey's and get that money off.
My wife knows that if her range is under 80 miles she can get 20 gallons in the tank.
My SX4 I never use the points on it unless I take a 5 gallon can with me, and same for my WJ - It has to be empty or have only 10 miles left if I want to use all 20 gallons and not give up that dollar LOL.
The truck I figured hell, it's got a 22 gallon tank, at 20 mpg if it says I have 25 miles range I should easily get 20 gallons in it. WRONG. It's the first vehicles to skunk us like that. I found if it's down to a range of 10-15 I can get 21 in it if I hold my face just right and turn one foot to the left and bend my right knee and salute the flag.

Grand Cherokee is a 24.6 gallon tank and I have easily gotten 23.5 gallons in it with miles still left to go. In other words, not empty, still about 40 miles range and I got within a gallon of capacity. I've been able to do that for the last 3 Grand Cherokees we've had - 2015, 2018 and 2021.
 

brianinca

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I pick my gas stations based on whether their nozzles work for my YJ. Jeep intentionally nerfed capacity on the YJ by putting a neck on the filler to kick the nozzle off at 15 ga. The "upgraded" 20 gal fuel tank just eliminated that neck restriction! My Sahara came upgraded but it still barfs gas and kicks off the fuel nozzles.

Just means the JT is a "real" Jeep.

Sorry, you missed the point, (and the fact I'm a decades long mechanic myself) as I am well aware of fuel expansion, having had multiple 500 gallon gas and diesel tanks on my farm when I farmed years ago. I have removed, repaired, cleaned, replaced, whatever, many dozens of auto and truck gas tanks.
I keep several large containers of gas around because of the equipment I have and we live a ways from fuel - and know you stop at the line or have gas on the floor on a hot day. I also know not to fill my classic cars beyond the states owner manual capacity or I'll have gas dripping at the rear center fill tube.

There are ways to design tanks to have 22 gallon capacity and have room for expansion. Every vehicle we've ever owned, Ford, GM/Chevy, even prior Jeeps, when the tank was virtually empty - you could get within tenths of a gallon of the capacity back in it (assuming the last 8 tenths were still there or you'd be on the road stopped out of fuel.)

My wife's Jeep - when she runs it down to 20 miles left, you can get all but full capacity in it. My Silverado was the same way.
This is the first truck that stops you at 18.5 when the capacity is 22 and you are down to 15 miles left.
I ran my wife's Grand Cherokee down to where she was giving me warnings like "if you run us out....." (and I knew I'd be in trouble) a few weeks ago and got within a half gallon of capacity in it without standing there milking the nozzle. She asked how much I got in it - and it was all but tank capacity. I had only pulled the trigger one time after it shut off the first time.

Can't do that with the JT.
They could leave head space in these and still allow 22 gallons of gas in them. All of our other Jeeps did.
This is a design issue with the JT. Look at those complaining that it kicks back at them, or other issues. I've never had so much trouble with anything I have ever owned or worked on getting fuel into it. If you stop where it kicks off - the gauge won't even read full on mine. That should say something.
They are advertising useful capacity on every other vehicle - if it says 24 (like another Jeep did) you could get 24 in it if empty and not squeeze hard. You could do 23 if it said "20 miles" for the range. Not the JT. They advertise 22 but you may get 19 in on a good day. IF you really really try yo can get more in.
Design issue. (poor design)
 

ShadowsPapa

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I pick my gas stations based on whether their nozzles work for my YJ. Jeep intentionally nerfed capacity on the YJ by putting a neck on the filler to kick the nozzle off at 15 ga. The "upgraded" 20 gal fuel tank just eliminated that neck restriction! My Sahara came upgraded but it still barfs gas and kicks off the fuel nozzles.

Just means the JT is a "real" Jeep.
Jeep figures if the thing is going to be standing on its butt going up a rock, or leaning at a 50 degree angle driving the side of a ravine, best watch the fuel level, eh?
 

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danielspivey

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They (manufacturer and EPA) don't want you to totally fill your tank because of emissions of gasoline and/or gasoline vapors from the vehicle. They must leave room for expansion of gasoline. Why? When you fill your vehicle with cold fuel from underground storage tanks, and that fuel expands due to the high ambient temperatures outside. The vapors need to go somewhere. The evaporative emissions system is designed to capture the vapors before those vapors reach the environment. When the tank is full of liquid, and that liquid expands into the container, that liquid gasoline reduces/destroys the ability of the evaporative emission system to function.

Although not apples to apples because it doesn't have an evaporative emission system, but I've filled my diesel pusher with a 90 gallon tank "too much" where I milked in as much as I could, took it 1 mile and parked it. Two days later I noticed that the vent had been leaking fuel on the garage floor. I put a container under it and captured another quart. Now I only fill it as much as possible if I'm gong to keep driving, and not parking it.

I'm not complaining about tank size myself... yet. My first tank got me 464.5 miles at 29.5 MPG per the computer, almost all highway driving, with some tailwinds.

It's been some years, but I recall the data label on the motorhome tank stating something like it should not be filled more than 90% of it's total capacity. If this is true for all motor vehicle tanks, your 22 gallon tank is likely designed to only fill to 19.8 gallons of gasoline and 2.2 gallons of vapor space.
A rubicon at almost 30 mpg? LOL. Where do you live that you drove over 400 miles downhill?
 

danielspivey

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Yeah, the bloody gas tank. OK, so it's a 22 gallon tank, at least let us get 22 gallons in it!
This bit about not getting more than 18.5 in unless you stand there for several minutes barely trickling gas in until you finally get 20-21 in the thing is weird.
They need to call it a 20 gallon tank. That's about all you can get in even when it's nearly dry.

There, does that fix the thread?
So I just tested your theory today, and it worked. I filled all the way up, until the pump stopped, gas actually splashed out a little. I then did what you said, slowly keep going. I got another 2.5 gallons in! It was almost like it’s not vented efficiently. It had to settle, slowly after 18.5 gallons. But sure enough, I was able to get another 2.5 in. Now I didn’t fill it to the brim, I couldn’t see gas at another 2.5. I stopped because it was cold out and it’s kind of a slow process.

I then drove 30 miles home, so if it “expands” like some say I don’t have much to worry about ;) Would I do this every fill up so I had to stop at the gas station 7 times verses 8 over the course of a couple months? Probably not. But on long trips I could see the value it adds.
 

Oil_Burner

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A rubicon at almost 30 mpg? LOL. Where do you live that you drove over 400 miles downhill?
Actually it was uphill all the way, from Gupton Motors in Springfield Tenn. to North East Ohio. That's mostly north, so it has to be uphill, right?

Diesel... that is what gave me the mileage. Unloaded, unmodified, new JTR.

Jeep Gladiator First long trip review + gas mileage/gas tank rant IMG_4624
 

danielspivey

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Actually it was uphill all the way, from Gupton Motors in Springfield Tenn. to North East Ohio. That's mostly north, so it has to be uphill, right?

Diesel... that is what gave me the mileage. Unloaded, unmodified, new JTR.

Jeep Gladiator First long trip review + gas mileage/gas tank rant IMG_4624
Delivered with zero miles?
 

Oil_Burner

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Delivered with zero miles?
11 miles.

When I got into the vehicle I didn't reset the trip and the MPG was just over 18. When I stopped to fill, I took that picture.
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