Filling gas shuts off with 2-3 gal additional

[josiahg52]

I'd rather not risk the vapor-recovery/evaporative-emissions system.


Adding more fuel can force liquid gasoline into the charcoal canister and vapor lines, which are meant for fuel vapor—not liquid. That can cause:

• Fuel spills or expansion overflow, especially in heat
• Gasoline odors and emissions
• A check-engine light or damaged EVAP components
• In some cases, poorer refueling behavior later

The simplest rule: stop at the first automatic shutoff.

You're not avoiding risk, you're just not filling your tank.

What if you go to another station with a different nozzle and you get another one or two gallons in before the first automatic stop? What if you only put five gallons in and it stops? That's it then? You drive away with half a tank of fuel?

You're method isn't conservative or safe. It's excessively risk averse.

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[wickncsu]

Generally advise against topping off. 3 gallons sounds… unusual though. Are you sure it behaves this way at all pumps?

Yes, some at slow delivery are faster than others which I guess increases foaming leading to the early shutoff.

 

[LostInAZ]

I did the "wait till the fuel light comes on test" and I also got about 16.8gals till first pump shut off. So does that mean that the tank still has about 2gals left of fuel or does that mean that the tank was NOT fully filled when the pump shut off? I guess the real test is to try a full tank and just drive till the engine shuts off and then refill and see how much you can fill it with. Any volunteers?

 

[sjm.esem]

well if you ruin your evap canister thats about a $600 part. so is it worth the extra $10 of gas you are able to get in worth that cost? and thats the cheap part of the evap system if i remember correctly.

someone with better knowledge can probably correct me.

its also know as the charcoal canister and over filling will pour gas into it and ruin the charcoal activator if i remember correctly.

I would day that the engineers should try and do a better job on the filler design then. Sounds kinda dumb that you can destroy your evap system, by putting in fuel.

 

[josiahg52]

I did the "wait till the fuel light comes on test" and I also got about 16.8gals till first pump shut off. So does that mean that the tank still has about 2gals left of fuel or does that mean that the tank was NOT fully filled when the pump shut off? I guess the real test is to try a full tank and just drive till the engine shuts off and then refill and see how much you can fill it with. Any volunteers?

That sounds normal, about two gallons reserve.

I don't advocate filling the tank of any gas vehicle to the brim due to the known issues it can cause. I also think blindly filling only to the first auto shutoff is not always going to effective, but it's the no thought required method. I don't have a 4Runner yet so I guess I shouldn't criticize any one doing what they do. I just compare it to my other vehicles where I've tracked every mile, every gallon I've put in there: almost 90k on one, 140k on another, and 75k on my truck. I generally know within 0.5 gallons how much will go in each tank depending on where the needle is on each gauge, if the low fuel/reserve or low range (where equipped) warning is on and how far I've driven since then. That's not because I'm smart, it's because I have data I can use. I plan to do the same with the 4Runner.

 

[Nodak]

I would day that the engineers should try and do a better job on the filler design then. Sounds kinda dumb that you can destroy your evap system, by putting in fuel.

isnt part of the evap system is to catch and neutralize gas fumes ? where do you expect them to put the canister to catch those fumes? you can only put it so high above the actual gas to catch them?

but if the owner is constantly filling that neck feeding to the tank up past the evap canister opening that the engineer thought was high enough to ensure you dont feed fuel into the canister if you dont over fill fuel system hardware.

i mean i have seen people fill the neck to the point where you can actually see fuel in the filler port.

and i am guily of doing that years ago back in the 2000's but stopped doing it.

 

[Hadelson]

I always pump one additional "shut-off" click after the first shutoff and usually get about .3 to .8 gal more this way.

I follow this above without any issues.

 

[josiahg52]

I would day that the engineers should try and do a better job on the filler design then. Sounds kinda dumb that you can destroy your evap system, by putting in fuel.

The purpose is to recover fuel vapor and burn them off with normal engine combustion. The system uses tubing/piping, solenoid valves, check valves, and engine vacuum to draw the fuel vapor into the engine air intake. Damage is caused by overfilling with fuel, not a bad design.

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