I've had this "thing" happening with my P5 lately, and I really can't figure it out. I'm hoping someone can shed some light on it.

First off, my car is about 15 months old, with about 31,000 miles. This problem started about 2 months ago:

When I go to certain gas stations (actually, this continues to ocurr at 3 nearby stations, making me think it's the car - but still won't happen at at others), the pump will stop LONG before the tank is full. In fact, it will run full blast for maybe 5 seconds, then click off at the handle like the tank is full. Then I have to squeeze the handle a few times to get it to start running again, and the same thing will happen 5 seconds or so later.

It's becoming VERY annoying, as it sometimes takes forever to fill the damn tank. I occasionally try to pull the "trigger" to only half of the fastest fill rate, and this helps, but not always. It's as though the pumps believe the car is full when it is not. Sometimes changing the angle of the nozzle in the gas tank tube helps, but again - not always.

This happens regardless of other conditions - the car can be hot or just warm, the outside temp can be hot or cold, the tank can be half full or near empty, the car can be running or off. It makes no difference if I try to "fill it up" or if I just put $10 in the tank. It also has nothing to do with those nozzles that have the vapor return "sleeve" over them - the part that gets pushed back when you put the nozzle in the fill tube - I've had the same thing happen whether the pump has this type of nozzle or just a regular one with no "sleeve". There are no "check engine" lights, and the car runs perfectly. And I'd guess it happens at 50% or more of the gas stations I visit. I've tried to think of all the outside variables that could cause this, and I can't come up with any.

Is this some sort of vapor venting problem? Anyone have any ideas as to what might cause this? Anyone ever experience the same thing, either with a Pro or another car?

Any thoughts would help. My car has not been to the dealer for any type of service, as it has been flawless from day 1. But I am considering making myself an appointment for this. I only worry it'll be one of those "could not duplicate the problem" things, so some insight before I go could help.

Thanks all.

~HH

 

i have had the same problem. the last 4 times i have put gas in the car it will put a couple of gallons in and then gas just sprays out everywhere. this is something just recently at 2 different gas stations. but when we fill the other car up nothing like this happens.

 

I understand the "filling of the pipe" - but I'm not sure this is what happens. Rarely do I hear the gurgling sound of gas coming up the pipe, and it has never sprayed out on me. Also, I have tried reducing the flow of the gas, and this only helps sometimes - not always.

I'm wondering if the pipoe is just poorly designed somehow - that at normal fill rates, there is a turbulence in it that keeps the gas from flowing down smoothly.

Dunno - Keep the responses coming. I'm still thinking about calling the dealer, as this is really getting irritating.

~HH

 

I really think it might be something in the design of the pipes as we have this issue on both our P5 and our MPV. Both Mazda vehicles, both with the same problem. Perhaps the angle is too steep or not steep enough that the gas would flow evenly through it to the tank. Maybe it trips the sensor on the gas nozzle to shut it off because the pressure is too great or there is too much backpressure. Hell I don't know, but we have the same problem on two Mazda vehicles.

 

Try to pull the nozzle out a bit. Don't put the entire nozzle into the tank...3 to 4" is all you need. If you put in too much air from the tank couldn't escape so you'll end up with gas backing up and trigger the nozzle to stop pumping.

 

When I fill up my P5 the nozzle shuts off earlier than on any other car I've owned -- about 1.5 gallons short of a real fill. Up til that point it fills normally, though -- then I gradually add the last gallon and a half, fill-click-fill-click, etc. It's annoying but I always figured it was just the design of the filler pipe. This doesn't sound as extreme as what you're experiencing, however.

 

I used to notice the same problem too. Like already suggested, just pull the pump out a bit. That should solve that problem.

The 'funnel effect' doesn't apply here because you are sticking the nozzle into a larger pipe. Since the pipe is larger, it should be able to handle as much flow as the nozzle can pump out.

 

It could be a problem with the anti-overflow valve in the fuel filler pipe (I'm not sure if this is the exact word that the manual uses for this part; I'll double-check my FSM later). 99 Miatas had a TSB issued for this exact same problem. Basically, there is a valve in the filler pipe that is supposed to stop the tank from overflowing, but if it's faulty, it will create too much backpressure and fool gas pumps into thinking that the tank is full, making them shut down too soon.

However, this can also be caused by a faulty gas pump. If I were you, I would actually hang out at the gas station after this happens and see if other people have problems with the same pump. This will tell you if it's actually a problem with your car.

 

No that sure wouldn't make you look like a freak


Hehehe, I just squeeze the nozzle half-way after it first stops and then it works fine.

 

I sometimes have the same problem with my car and my moms Mazda MPV. I usually release then start again.

 

all them damn fumes? flow too fast, and it's "tricked" into thinking it's full? just pull the nozzle out a bit...

 

Well, I'm off to work in a few minutes, and I need to fill up.

I'm pretty sure I've tried just about everything suggested to solve this - and none of the solutions really work.

I guess we'll see what happens....

~HH

 

just launch a gallon or so on the gorund and swear profusely at the gas company. then in a large commanding voice ask: "where's my zippo?" LOL

just kidding, don't do that.

 

I have to ask your age...
When I worked at a gas station, that problem only seemeds to happen to 65+ year old men. And they swear up and down that it wasn't there car. So, after many cracks in the "heed" by walking canes, I'd say it's not the car! LOL!

It could be the pumps are set sensitive. It also could depend on the amount of gas in the ground tanks...and the temp. The gas in the ground is usually about 10-15 deg. C. When the temp outside is hot the gas can expand and vaporize quickly (you can usually see it escaping as you fill your tank.) As the fuel gushes down the filler pipe, the excess vapors cause a backwash of pressures that fool the pump into thinking the tank is full.

I think this could be more appearent in a car with a smaller filler pipe diameter.

They call me the professor, becaus I have all the useless knowledge!

 

Dude - I'm 29 and I'm not a ******* idiot.

I've owned no less than 9 vehicles in that time, and this is the only car that I've ever had this issue with. In fact, many of the stations at which this problem ocurrs I've been using since I had other cars - with no issues. So I am QUITE sure it is the car.

The other thing is that this has only been happening for the past 5000 miles or so - the first 25k miles went without a hitch.

I filled up this morning, and it seems that if I hold the stupid nozzle at the PERFECT angle and depth, the problem "goes away". But the second I move a 1/4", the thing clicks off. Way too sensitive, and something has got to be a bit askew.

If you had read the original post, you'd have seen that I stated this problem ocurrs REGARDLESS of other conditions, including air/engine temperature, and it happens at several stations in several locations - and in case I forgot to mention, the existing fuel level in the tank has no effect on it either.

I'd like to thank those of you who have responded with constructive advice - particulary the post about the overflow valve in the fill pipe - I will absolutely present that to the dealer, as I plan to bring this issue up with them before the 50,000 mile warranty period expires.

Professor?

~HH