# ECO MT gas tank max capacity question



## jblackburn (Apr 14, 2012)

http://www.cruzetalk.com/forum/57-how-library/12035-how-15-6-gallons-into-eco-mt-tank.html

Tank is the same between all models; fuel pump assembly is different on Eco MT.


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## obermd (Mar 3, 2012)

The ECO MT has the same 15.6 gallon gas tank as the rest of the retail Cruzen. For a description of the gas tank modification to make it easier to access the top three gallons, take a look at http://www.cruzetalk.com/forum/57-how-library/12035-how-15-6-gallons-into-eco-mt-tank.html. In a nutshell, the tank's main vent is on the fill level sensor. In the ECO MT there is an extended shroud on this vent that has the effect of stopping the non-fill pipe venting of the tank three gallons early. From the advertising for the Cruze in Europe, we can safely assume the fuel evaporation recovery system vent pipe is near the top of the fill pipe. European Cruzen are advertised with a 60 liter gas tank, which is 15.85 US Gallons. Filling above this level risks soaking the carbon filter in the evap control system. The gasoline will evaporate back out of the carbon but the detergent additives won't, which means that if you do this too much you risk reducing the effectiveness of the gasoline evap control system.

You don't need to replace the fuel pump to get a complete fill of the ECO MT's gas tank. All you need to do is trickle fill the tank after the first click. This involves holding the pump handle in such a manner that it doesn't put more than about a penny's worth of gasoline into the tank per second. Any faster and you will get gasoline backing up in the fill pipe which will click off the pump again. From experience first click is actually somewhere between 11 and 11.5 gallons total fill, meaning you can get from 4.5 to 5 additional gallons into the tank after first click. This is how I filled my gas tank prior to my 814 mile tank. I do NOT have the fuel pump modification.


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## brian v (Dec 25, 2011)

Another reason for me to call you a Goofer Ball ! You are still going to drive the same amount of miles every day . So whom cares if you mess up the evap cannister . Only you . Goofer Balls ..


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## newsguy99 (May 24, 2013)

I put over 16 gals of gas in mine one night.. And according to the DIC I had somewhere around 1 gal left in the tank. Pics are in another thread here talking about gas tank size.

And here's the post about that..

http://www.cruzetalk.com/forum/9-ge...owner-needs-know-confirmed-20.html#post210838


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## Merc6 (Jun 8, 2013)

Overfilling the ECO tank is fun, you make mpg plus how long you can hold the fuel needle on full before it moves bets. 

Longest I got before it moved

















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## obermd (Mar 3, 2012)

On both my 715 and 814 mile tanks the needle didn't start moving until somewhere around 225 miles.


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## chevycruze2012 (Nov 13, 2012)

So from my understanding, GM had a fuel shut off sensor in the eco's for 12.6 gallons but it has a 15.6 gallon tank? I would like to do this in mine, but i seem to have bad luck trying to trickle pump it bec gas comes pouring out. And yes it was in my eco. I filled it up completely one night after work and i put in 13 gallons or so and it started coming out. I stopped pumping gas and went inside and bought a bottle of water and flushed the gas off the car. Luckily it didnt do anything to it. So whats the trick for me now since i already tried trickle pumped it.


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## obermd (Mar 3, 2012)

It's not a sensor - it's a shroud that extends down from the vent. As the gas fills in the tank it will eventually block this vent. The ECO MT's shroud causes this blockage to occur three gallons early. As for trickle filling, it takes practice and patience and unless you are in one of those situations where the extra three gallons means going to the gas station once per week vs. twice per week it really isn't worth worrying about. I used week, but it could be day, month, whatever - you chose your time period for the statement.


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## chevycruze2012 (Nov 13, 2012)

Okay. that makes sense now. My pumps around here keep shutting off for every click in so many minutes i think. Its hard to explain lol. Not trying to be a pain.


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## iKermit (Dec 13, 2010)

That's why you keep clicking lol... It will take patience


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## Merc6 (Jun 8, 2013)

It is experience with extremely slow pumping and the gas station pumps. A pump that already pumps slow is easier to control or manipulate. I have the nozzle out but still in contact with the metal filler neck and watch it fill. I also don't full throttle the pump till 1st click as it's all foam fighting you the rest if the top off. My top offs sole purpose is so I can carry Shell 93 V power all the way from Cleveland to NJ bypassing a fill up of Sunoco only stations on the PA turnpike. 12 gallons require me to stop and fill before I reach my almost 500 mile trip and I never got good mpg on Sunoco when I used it. In town, trickle fill would sit in the car and be older than I would like it to be by the time it runs down to 57 miles to empty light. Less pump price and fresher product is why I don't go past 13ish gallons on normal fills. 


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## chevycruze2012 (Nov 13, 2012)

Would pulling the gas nozzle half way out of the filler neck help at all? I know this has something to do with pressure or blockage in the filler neck. I might be looking at it all wrong or thinking of it differently. So please enlighten me here guys.


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## Merc6 (Jun 8, 2013)

Yes pulling the nozzle out but leaving the metal to metal contact. It takes patience plus lighting so you can see the nozzle end and the bubbles, better when it's warm out. Being almost 19*F on morning full ups may not be the best time to try and learn the trick granted you are losing mpg from winter mix if you are in the areas that do it. You have to be able to get the pump to pump slow enough the person on the other side of the island can cause your pump to shut off when they keep clicking to top off. I pump regular(just below the 1st trigger lock notch will engage) till the 1st 3 clicks then start the process. Once you get the technique down, you should be able to fill just fast enough the bubbles never leave the neck till the very end. If you ever had a water fountain that never made a full ark farther than the metal shield, that's about how fast I pump. Any faster than that for the pump I use and I will get splash back. 


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## chevycruze2012 (Nov 13, 2012)

Yeah okay. Yes that's annoying when your trying to pump gas and the person on another pump keeps hitting the trigger causing yours to "mess up" the flow of fuel. Not sure how I wanted to say that lol. I hope u get what I mean. They say the best time to fill up is when its cool like in the morning or at night. Im sure it depends on how cold or cool it is outside.


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## Merc6 (Jun 8, 2013)

chevycruze2012 said:


> Yeah okay. Yes that's annoying when your trying to pump gas and the person on another pump keeps hitting the trigger causing yours to "mess up" the flow of fuel. Not sure how I wanted to say that lol. I hope u get what I mean. They say the best time to fill up is when its cool like in the morning or at night. Im sure it depends on how cold or cool it is outside.


Yes, mornings are best with no fuel truck present. I was saying it's going to be difficult trying to learn in blistering cold vs 79*F weather as pumping slow may be harder with gloves and painful if you go rogue(no gloves) for that long if a time period.


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## newsguy99 (May 24, 2013)

I found that a Shell station around here, with the lowest price on Vpower 93, has the slowest pumps as well... I can actually get it to be so slow, I can see the numbers one by one count on the amount of fuel being put into the tank, and then can see each number from the dollar amount as well.. Its great at filling with that pump, on a super slow fill...

Kroger pump I use, just can't do that, as well..


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## Gus_Mahn (Aug 16, 2011)

I have a '12 manual Eco with the 15 gallon module installed. It holds about 15 gallons till the pump clicks off when empty. It will hold between 2.5 to 3 gallons more trickle filling into the filler neck after the pump first clicks off. Some pumps work better for trickle filling than others. Even then, it's slow. It takes about 10 minutes to get in three extra gallons into the tank.


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## Merc6 (Jun 8, 2013)

newsguy99 said:


> I found that a Shell station around here, with the lowest price on Vpower 93, has the slowest pumps as well... I can actually get it to be so slow, I can see the numbers one by one count on the amount of fuel being put into the tank, and then can see each number from the dollar amount as well.. Its great at filling with that pump, on a super slow fill...
> 
> Kroger pump I use, just can't do that, as well..


Yep, my slowest pump is Shell as well. The BP pumps aren't slow enough to trickle without splash back. 



Gus_Mahn said:


> I have a '12 manual Eco with the 15 gallon module installed. It holds about 15 gallons till the pump clicks off when empty. It will hold between 2.5 to 3 gallons more trickle filling into the filler neck after the pump first clicks off. Some pumps work better for trickle filling than others. Even then, it's slow. It takes about 10 minutes to get in three extra gallons into the tank.


It's about 7 or so if you keep the right pace so you aren't filling to the point it comes out of the filler neck. The bubbles stay almost an inch from the opening so you can see how full it's getting. For me it's more foams looking for 13-14 gallons than the 15ish gallon mark. Once it's almost full I get the bubbles that kinda look like the beer glasses that have the pattern on the bottom to control how they rise to the top of the glass. I actually stop at that point instead of seeing the fluid sit near the fill cap point. My goal is more than 500 miles so I always have just enough to drive around for a few days before I return home stopping at that point. 


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## obermd (Mar 3, 2012)

Merc6 said:


> It is experience with extremely slow pumping and the gas station pumps. A pump that already pumps slow is easier to control or manipulate. I have the nozzle out but still in contact with the metal filler neck and watch it fill. I also don't full throttle the pump till 1st click as it's all foam fighting you the rest if the top off. My top offs sole purpose is so I can carry Shell 93 V power all the way from Cleveland to NJ bypassing a fill up of Sunoco only stations on the PA turnpike. 12 gallons require me to stop and fill before I reach my almost 500 mile trip and I never got good mpg on Sunoco when I used it. In town, trickle fill would sit in the car and be older than I would like it to be by the time it runs down to 57 miles to empty light. Less pump price and fresher product is why I don't go past 13ish gallons on normal fills.
> 
> 
> Sent from AutoGuide.com App


This ^^^ The only two times I've had gas so bad I needed a complete fuel system flush and clean were both Sunoco.


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## Eddy Cruze (Jan 10, 2014)

Most gas stations are equipped with pumps that have vapor recovery systems to recover gas vapors keeping those vapors from getting into the air. If you top off your tank it will cause you to pay for gas that is drawn back into the gas station's vapor recovery system. 

The extra gas you are trying pump may be drawn back through the vapor recovery system into the station's tanks. Then in essence you are paying for fuel that is not going into your tank but is going into the gas station's tanks. This, of course, raises your cost of gas.

When you overfill your gas tank it is almost a certainty that gasoline will evaporate or will be spilled. If either of these or both of these occur it means buying gas that is not getting into your car. That has to hurt you in the wallet.


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## obermd (Mar 3, 2012)

Eddy Cruze said:


> Most gas stations are equipped with pumps that have vapor recovery systems to recover gas vapors keeping those vapors from getting into the air. If you top off your tank it will cause you to pay for gas that is drawn back into the gas station's vapor recovery system.
> 
> The extra gas you are trying pump may be drawn back through the vapor recovery system into the station's tanks. Then in essence you are paying for fuel that is not going into your tank but is going into the gas station's tanks. This, of course, raises your cost of gas.
> 
> When you overfill your gas tank it is almost a certainty that gasoline will evaporate or will be spilled. If either of these or both of these occur it means buying gas that is not getting into your car. That has to hurt you in the wallet.


While true if the gas is actually coming back up the fill pipe, the "missing" three gallons are actually still in the tank.


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## Eddy Cruze (Jan 10, 2014)

Aren't those 3 gallons dedicated to cooling the pump? I'm just saying in California for years we have known if you try to overfill a tank the gas will turn around and be sucked into the stations tank, not ours!


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## spacedout (Dec 7, 2010)

Eddy Cruze said:


> Aren't those 3 gallons dedicated to cooling the pump? I'm just saying in California for years we have known if you try to overfill a tank the gas will turn around and be sucked into the stations tank, not ours!



Eddy your forgetting the ECO manual transmission cars have a restriction in the tank that makes the pump shut off 3 gallons early. They use the same 15.6gallon tank as all other gas cruze but with this restriction at first click they are only at 12.6 gallons. This restriction is part of the fuel pump assembly & from other threads can be swapped out to gain full capacity. 

This is part of the weight reduction GM did to get that magic 42mpg highway with the ECO.


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## xczar (May 19, 2013)

Sorry if I missed something here but, after I read some of this topic on the original thread and this one, is this issue only with pre 2013 models? I have been filling my 2013 ECO automatic for over 22k miles with 13, 14, and 15 gallons without any 'rain dance'. I recall my manual even says 15.6 gallons.


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## Merc6 (Jun 8, 2013)

xczar said:


> Sorry if I missed something here but, after I read some of this topic on the original thread and this one, is this issue only with pre 2013 models? I have been filling my 2013 ECO automatic for over 22k miles with 13, 14, and 15 gallons without any 'rain dance'. I recall my manual even says 15.6 gallons.


ECO auto and ECO diesel doesn't apply to this thread. 


Sent from my iFail 5s


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## NickD (Dec 10, 2011)

We leaped from the Eco to the 2LT so we could get a compact spare with a manual transmission. But to compensate for that 18 pounds of extra fuel, went on a diet to loose 18 pounds. 

But after driving about 120 miles back to that 18 pound savings again so can eat a large meal. Nice being on summer gas to see 628 miles remaining before the next fill up.

Actually, those extra 18 pounds do help when coasting down a hill. To get maximum fuel economy, does help to leave the cruise off and hold the gas pedal steady when going down the hill, but will pick up 12-15 mph extra, that you will lose when going up the next hill.

But the law won't let us do this and the key reason they said they dropped the speed limit to 55 mph is to save on gas. That gets me to wonder if I could fry my brain with drugs, maybe I could run for office.


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