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Trouble filling up the gas tank

Hi all,

I recently purchased a 2014 Mazda2 with roughly 55,000 miles on it. Yesterday, for the very first time that I’ve owned the car, I noticed that while attempting to fill the gas tank, the gas pump kept shutting off, as if the tank were full. Having never experienced this when previously filling the tank, I chalked this up to a faulty pump and went on with my business. But this morning, the very same thing happened at a different gas station.

This afternoon, I brought the car to the mechanic. He did some diagnostic work and proposed that the gas filler neck needs to be replaced. Does this sound right to you all? Are there other possibilities? If so, what can I expect to pay to fix the problem?

Thanks in advance for your help.

Are you in the habit of squeezing the last possible drop of gas into the tank? If so, you may have flooded the evaporative emission sytem, which can cause this symptom.

No, I’m not, but I suppose it’s possible that the previous owner was.

Before spending (serious) money, maybe try a simple workaround, like holding the pump handle/nozzle at different angles to see if it prevents the early shutoff.
Maybe try 45 degrees to the left or right (instead of straight down), and if that doesn’t work, maybe 90 degrees, etc.

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The problem might be with the Onboard Refueling Vapor Recovery system.

This system allows the gas tank to vent as the gas tank is filled.

If the there’s a restriction in this system, the gas pump nozzle will keep shutting off.

One thing that can cause this problem is spiders laying egg sacs in the ORVR system.


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Definitely a possibility.
Exactly what diagnostic work did he do?
Did he explain exactly what he felt was blocking the filler neck?

It’s possible that it was the inability of the air in the tank to vent rather than the gas to pass due to a gasoline-saturated charcoal bed passed on to you by the previous owner.
But it’s also possible that the prior owner’s little one wanted to see how well his plastic Buffalo Bob character would fit down the filler hole.

When I bought my house the bathroom sink wouldn’t drain properly. After disassembling it I discovered a toy in the trap.

Tester’s idea has possibilities too. I seem to recall having read that Mazda issued a recall regarding the spider problem. Apparently they have a mod that’ll prevent the little buggers from getting into the vapor recovery system. You may want to check this out.

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This is interesting! Posted by americarOct '10

americarOct '10
My guess the reason for the slow pumps maybe do to the vapor recovery nozzles combined with all the pumps being used at the same time. This possibly causes the pumps vapor recovery system to not allow the gas to pump any faster then the vapor it can recover. I try to avoid stations in my area that have this problem. But I never experience a slow pump to cause inaccuracy of the pump.

You can try filling the car on low speed, may be a pain but better than chasing ghosts. If you have no check engine light and can live with it give it a whirl.

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That isn’t the post I was answering. The post I was answering was posted on January 2, 2018 by an OP named Inqahoots.

Thanks for your thoughts, everyone! If indeed it is the filler neck, as the mechanic suggested, any thoughts on what may have caused the problem in the first place? And why it came on all of a sudden?

If this was the former rental car that supposedly received a new engine there may be more to the story than you were told. Maybe when the alleged bottoming of the vehicle damaged the oil pan it also did something to the fuel pipe brackets.

I do not understand all of a sudden, Yesterday was your first fill up, may have been going on for years.

Sorry, should’ve been clearer: the problem occurred on my third and fourth fill-ups. No problems previously.

Yes and I apologize for speed read, but previous response would still be applicable.

Gotcha. Thanks.

I wouldn’t guess the problem to be the filler neck. Is there a specific reason they mentioned why that might be the problem? We get this same complaint here quite a bit, not just mazdas but most brands, and the problem is almost always in the evap system. There are valves involved, some are supposed to open and some close, to prevent this problem. My guess, either one of the valves is faulty or the evap canister is kaput. If you google “mazda purge valve” you’ll find some more info and utube videos about how to diagnsose and repair this problem.

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I have found that on some vehicles, if you jam the nozzle as far into the filler neck as you can, this will happen. Try backing it out about a 1/4", the nozzle handle should then sit slightly lower and the nozzle itself more parallel to the filler tube.

When it is jammed all the way in, the nozzle is squirting gas at the side wall of the filler neck causing back splash that shuts it off.

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Just wanted to offer a quick update, as I had the opportunity to talk more with mechanic this morning: he says that he would start with the filler neck (a $550 job, it seems – ~$300 for the part, ~$250 for the labor) because he noticed that “door” that sits at the top of the filler neck and the gas cap is missing, and that this could be the source of the problem. But he also encouraged me to first bring this to the Mazda dealership and see whether they’d be willing to fix this under their warranty.

I’m not terribly optimistic about my prospects with the dealer, but I suppose it’s worth a shot.

Modern vehicles don’t have that door and you are driving around without a gas cap?

There is a check ball at the fuel tank inlet that can cause a fill problem but it is normally located in the tank inlet, not the fill tube.

These fill problems are sometimes caused by a sticking fuel tank over-fill control valve. You need someone with experience to diagnose this, try the dealer.

I’ve been trying to confirm whether or not this car ever had the door. Not yet clear to me.

And rest assured: there’s definitely a gas cap on this car!