Subaru Outback Forums banner
1 - 15 of 15 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter · #1 ·
Hi friends,

We have 2013 Subie OB with 41k miles on it, the other day we were not able to fill gas despite fuel indicator showing 50% tank full (or empty). We thought it was a faulty pump perhaps, tried another gas station, same issue. The gas pump keeps on shutting off as if the tank is full, so we end up refueling the car at 1/10 of the normal rate and end up spending 10-15 mins filling the tank, as the moment you refuel too fast, the pump shuts off. If it does not shut off, it ends up spilling.

Now we're on a 500 mile road trip and stopped at several gas station, same thing at every gas station, spending 10-15 mins filling the tank (from 50% level).

Any thoughts on what this could be? Did some quick searches leading me to believe that perhaps the line from gas tank to vapor canister may be blocked, worst case the vapor canister may be "full" and needs to be replaced which is $4-500 for parts alone.

Any input would be greatly appreciated. Heading back home tomorrow, another 500 miles and long stops at gas station. Have bought a funnel which may help let the air out of the gas tank whilst refueling.....hoping the refueling process goes faster. I normally refill once the gas level hits 50% and stop the refueling process at 10 gallons, as I would not know if the pump shut-off is due to me filling too fast or tank being full so....

Cheers!
plex :)
 

·
Registered
Joined
·
19,632 Posts
. . . Did some quick searches leading me to believe that perhaps the line from gas tank to vapor canister may be blocked, worst case the vapor canister may be "full" and needs to be replaced which is $4-500 for parts alone. . . .
I think you have the idea. The symptoms are not uncommon.

When fuel is being pumped into the tank, the fume-laden air in the tank has to go out. Rather than escape into the atmosphere, it's routed to the canister, where the gas fumes are trapped by the charcoal. The scrubbed air is then exhausted through a drain valve and filter. If this path is blocked and the air can't move out of the tank, fuel from the nozzle backs up in the fill tube and triggers the gas pump nozzle to shut off.

The drain valve, which is normally open, or the filter could be blocked/restricted by deposits/dirt etc. (Note: an electrically defective drain valve i.e., open or shorted, should trigger a trouble code and CEL.) There have also been cases in earlier years of insects getting inside the drain tube (there was no external filter) and blocking it with a nest.

Canisters usually don't become "full", but can prevent air flow if the car is driven in high water, enough to flood the canister, or if the gas tank is regularly over filled, typically by running the nozzle well after it had first shut down automatically (in a system that is otherwise working properly).

The canister is behind the left rear wheel, and the filter is up above rear sub-frame more toward the center of the car. Neither appears to be readily accessible without having the car up on a lift. The location of the filter might require dropping the sub-frame to inspect/replace. Probably requires a visit to a shop. (Is the car still under any warranty?)
 

·
Registered
Fresh Out of Outbacks!
Joined
·
14,499 Posts
Blocked hose is much more likely than a canister problem.

In cold weather, water vapor can freeze into an ice block in that hose. Granted that's unlikely within 500 miles of Virginia today, just listing it in case someone finds this thread later.
 

·
Premium Member
(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
Joined
·
18,868 Posts
are you or another driver in the habit of 'topping off' the car's tank or rounding up to an even dollar amount?

is the car new to you?
 

·
On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
Joined
·
27,285 Posts
I normally refill once the gas level hits 50% and stop the refueling process at 10 gallons, as I would not know if the pump shut-off is due to me filling too fast or tank being full so....

Cheers!
plex :)
a outback like yours has a 18.5 US gallon tank,

so maybe 17 of that the max you could ever get in,

I have been driving since 1990, over those years I have had cars want to fill slow or puke gas back on the ground,
...none recently that I recall, and over those years I never changed a part in a a vehicle to fix the situation, ...kind of a regular thing in car ownership that randomly comes up.

advice: run the car down to 1/4 tank on the dash gauge.

then use your funnel,... (goal to get a hard funnel below the metal flapper). and leave it there for 5 minutes.

these two things "may" expel any pent up fumes, and reset any springs / flappers that are causing the problem.

the above is a opinion,...free to read, free to try.

____

alternatively I guess something could happen due to something getting a little gummy due to dry residue somewhere.

_____

if you did have a evap system that was really failing in someway and needing a part, I would think you would get a check engine light code specific to that system,..or some added rough running or odd code.
 

·
Registered
Joined
·
19,632 Posts
If the drain valve system is completely blocked, there would probably be problems with fuel delivery and trouble codes generated when the ECM carries out regular fuel system integrity tests. However, a partial restriction of the canister drain system might not cause these, but still prevent rapid filling of the fuel tank.

When the engine is running, the drain valve is supposed to be open (default), allowing air to enter the fuel tank through the canister, to replace fuel pumped out of the fuel tank to the engine. For every gallon of fuel pumped out, the same volume of air has to enter. Let's take the example of driving at 60 mph at about 25 mpg. At that rate, it would take about six hours to use about 15 gallons. In other words, 15 gallons of fuel is replaced by 15 gallons of air in the tank in six hours.

Next, let's look at the filling process. The tank is down 15 gallons. How long does it normally take to replace the 15 gallons and displace the equivalent volume of air in the tank? According to https://en.wikipedia.org/wiki/Fuel_dispenser#Flow_measurement, in the U.S., fuel flow when filling is limited to 10 gpm. At this rate, it would take 1-1/2 minutes to displace 15 gallons of air through the canister and drain. At a more moderate 5 gpm, it's three minutes. That's a much higher rate of expelling air from the tank than the inflow of air when the car is being driven.

Consequently, with a partial restriction of the drain, there might not be any performance issues, or trouble codes generated, because both involve fairly slow rates of air flow in through the drain and canister, whereas when filling, much more air, per minute, has to move through the drain.

I will add, however, that sometimes the problem of slow filling isn't the evap systems etc. There was a case here, I think in the last year or two, where the problem was traced to a faulty fill tube. One possibility is an internal collapse in the rubber sections that restricts the entry of gasoline into the tank itself. ( http://www.subaruoutback.org/forums...ump-kicks-off-when-filling-2.html#post2084378 ) Another relates to a device that might be in the fill tube to prevent siphoning. As I recall, one is a type of valve involving a ball that is normally lifted from the valve seat by a spring, allowing fuel to pass around the ball and down into the tank. When a siphon tube is inserted, it comes against the ball, pushing it against the seat which blocks even a flexible siphon tube from getting around and into the tank. (There might be variations of this idea.) If the anti-siphon valve is damaged such that the ball doesn't lift away as it should, it could block, or at least slow, the flow of gasoline.

Then there's the possibility of something solid having been put down the fill tube that is similarly restricting flow into the tank.

Regardless, there should normally not be any problem filling the tank at reasonable rates up to the maximum permitted.
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #7 ·
Hi all,

Apologize the late reply. Thank you all for your good, detailed and lengthy feedbacks, much appreciated.

To answer some of your questions:

Is the car still under any warranty? Unfortunately not, just passed the 5yr ownership mark approx 2 weeks ago.

In cold weather, water vapor can freeze into an ice block in that hose. Car is in VA and garage kept so not experienced any frost.

is the car new to you? Nope, we're the first owners, factory ordered the '13 in mid 2012 as soon as Subaru allowed to place orders.

are you or another driver in the habit of 'topping off' the car's tank or rounding up to an even dollar amount? Wife is the primary driver of the car and I knew that she had the habit of rounding it up to nearest 8th cent (which is just a few extra drops of gasoline), but upon further conversations, she told me that she (in addition) also had the habit of fill till an extra click at the gas pump before rounding to nearest 8th cent. Asked approx how much gas went into the car between first and second click, she told me between $1 and $2 worth of gas.....which means she topped it off approx 2 to 3 quarts of gas based on todays price.

advice: run the car down to 1/4 tank on the dash gauge. then use your funnel,... (goal to get a hard funnel below the metal flapper). and leave it there for 5 minutes. Thank you, I'll give that a try once we hit approx 1/4 tank

I did some further searches online (generic car forums, not specific to Subies') and some mentioned that is could be a stuck anti-spill roll-over check valve, see the following links with responses from Caddyman

https://community.cartalk.com/t/weird-gas-tank-problem/5363/3
https://community.cartalk.com/t/gas-filling-problems/38242/7

According to him, running a another smaller pipe down the filler neck and pushing the stuck ball should help. Possible that the overfilling of gas can cause the check valve/rollover valve ball float so high that it ends up getting stuck in the high position, plugs the filler opening, thus causing slow gas fill?

Cheers,
plex :)
 

·
Banned
Joined
·
6,264 Posts
I have the same issue with my '15 at one particular station. I find if I only insert the hose 2" or so instead of all the way I can continue to pump until the tank is full.
 

·
Premium Member
(formerly) 03 H6 OBW , (presently) 06 WRX Sportwagon & 2021 Honda CR-V
Joined
·
18,868 Posts
that seems like a serious habit of overfilling to me - possibility the canister is flooded. (I admit I can't be certain based on the described behavior of the pump....) There is a weight limit and, if , for instance, a canister is supposed to weigh 2 pounds, a flooded one might weigh 7 or w'ever. I think dealerships have a procedure to determine when a canister should be replaced. Not cheap BTW.

I suppose an independent mechanic might save you some money for this procedure, and something as new as 2013, a canister from a wreck might be a good option to save $ on the part.

finding a way to pull the hose from the 'input' side of the canister when filling, and compare to behavior with only the 'output' (drain?) hose disconnected, should be diagnostic for a flooded canister. This would not be easy on most cars - again, a sympathetic independent mechanic may be the best way to try diagnosing this. Removing it and checking its weight may actually be easier.
 

·
On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
Joined
·
27,285 Posts
if you can convince wife, to stop filling the car past the first click, the problem may "dissipate" :smile2:

I don't pump past the first click,....and I live 20 miles from the gas stations I typically buy gas at.

(just one rural expensive station 10 miles away that I usually skip).

actually in the modern era, the only people I notice that are actually pumping past the first click are some gas jockeys in NJ. (where, the state has a law against customers pumping, ...some stations want their jockey's overfilling,...some don't,...just the luck of the draw,.....but since their state gas sales tax went up I don't even bother to find my way to buy any in that state any more).

I bet you can read it right in the owners manual "do not pump past first click",...but who bothers reading such things.??
 
  • Like
Reactions: 1 Lucky Texan

·
Registered
2011 OB 2.5i Prem CVT HK/AWP, Ruby Red Pearl
Joined
·
3,321 Posts
... stop filling the car past the first click...
This... with my kids/wife too. Also set the nozzle trigger on the first notch/catch, prevents gas possibly puking on your clothes.
No need for a 13sec Nascar pit stop.
 

·
Registered
2013 Outback 2.5i Convenience
Joined
·
1,404 Posts
are you or another driver in the habit of 'topping off' the car's tank or rounding up to an even dollar amount? Wife is the primary driver of the car and I knew that she had the habit of rounding it up to nearest 8th cent (which is just a few extra drops of gasoline), but upon further conversations, she told me that she (in addition) also had the habit of fill till an extra click at the gas pump before rounding to nearest 8th cent. Asked approx how much gas went into the car between first and second click, she told me between $1 and $2 worth of gas.....which means she topped it off approx 2 to 3 quarts of gas based on todays price.
That could cause the issue over time. I am reasonably sure I read in the OM to not add any more fuel after the first click. Just checked, page 7-5 and 7-6 say do not add any more fuel after the pump shuts off.

It also says that fueling is a 1 person job, do not allow others to approach the area while refueling! Top secret stuff going on I guess!
 

·
On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
Joined
·
27,285 Posts
This... with my kids/wife too. Also set the nozzle trigger on the first notch/catch, prevents gas possibly puking on your clothes.
No need for a 13sec Nascar pit stop.
if "Non- Athletic Sport Centered Around ********" wanted to put all the fuel in the car, and spill nothing,
they would need people like the one in the green shirt here:

 

·
Registered
2015 3.6R Limited w/ES
Joined
·
4,449 Posts
...the only people I notice that are actually pumping past the first click are some gas jockeys in NJ. (where, the state has a law against customers pumping, ...some stations want their jockey's overfilling,...some don't,...just the luck of the draw,.....but since their state gas sales tax went up I don't even bother to find my way to buy any in that state any more)...
These days, in NJ, almost all stations will pump past the first click, up to the nearest dollar amount if you're paying cash (which many people do since the price is typically higher on credit). Even if we're talking 50 cents worth, the pump typically clicks off a couple times in the process, despite the fact that you're not really forcing that much extra into the tank.

If you pay with credit, I find that they only very rarely pump past the first click.
 
1 - 15 of 15 Posts
Top