It seems for a while now that while I'm filling my gas tank the pump will stop like the tank is full if I grip the handle all the way. Almost as if something is restricting flow and flooding the fill up tube. The only way to fill the tank up is to grip the handle ever so slightly and practically let it drip in.

I have dropped the tank before but I dont remember it starting right after that.

So tonight I took off the filler tube and there doesnt seem to be anything blocking flow and the flapper gate on the tank seems to be very loose also.

Before I put it back together does anyone have any input on what might be causing this issue?

 

Do you know for fact you are not full? The gas gauge isn't the most accurate thing.

In order to top of my tank I need to pull the (for lack of a better word) foreskin back on the nozel and let it vent.

There must be something about how our cars vents the tank. Perhaps the purge control solenoid is normally closed and therefore pressure only builds.

 

I do question my gauge at times but the tripometer says I've gone about 200 miles so I assume I should be able to put a little in. This problem occurs instantly as if I had just filled it up. There was also a time where I thought that some gas station did and some didnt but it seems to be all latly.

I guess also having knowledge of how the pumps work might also help solve the issue. Does it stop when the fluid level comes up to the spout on the pump or is it something else?

 

I think it works when the pressure inside the tank becomes greater than the pressure holding the trigger valve open. I think as the fuel enters the tank the rate at which the pressure builds increases as you near the top, but I could be wrong.

A quick google came up with a bunch of babble, but some seem to think it is the shape of the filler neck and churning gas triggering the shut-off.

read here http://ask.metafilter.com/mefi/17961

 

Our 04 GTP (grand prix) has done this since we bought it a couple years ago. I have to just barely hang the nozzle in the filler tube and I can go full blast then, but it doesn't always do it at all stations, so I'm assuming that maybe they have the pumps running a little faster than others.

I know it's not the same car, but just letting you know it's not just your car.

 

Well since I didnt see any issues I just put it back together and made sure the smaller tube had a pretty direct route to the tank. When I went to go fill up I had no issues at all. So I guess it is fixed.

 

I have the same issue you're describing. Sometimes immediately, other times I can put 5 gallons in and then there's still room for 4 more or so. If you find a fix post it up!

 

LOL!
If the pressure in your fill tube gets high enough, it triggers the diaphragm shut-off valve. When the gas station tanks are full, the pressure at the nozzle is usually pretty high when you pull the pump handle all the way, and if the nozzle is at a hard angle in the fill tube, the splashing will often cause enough pressure to trigger the shut-off valve.

 

I own a Chevron station in South Miami and the above statement is incorrect. The levels of the underground tanks have absolutley no correlation with the pressure at the dispenser hose. What causes the variation between a fast dispenser & a slow one is the actual fuel filter inside the dispensers. Cheapr station owners don't ever change the fuel filters, which causes a nasty buildup of residue in the filters, causing a slower flow of fuel to the hose & nozzle, just like an old fuel filter in your car would ceuse the same symptoms.

I actually test my dispensers on my jeep every month and using a stopwatch, if I can't pump 10 gallons under a minute, I change the filters....this tends to happen normally every 6 months. Regardless of which dispenser is slow, I change them all. Each grade in each dispenser has it's own filter (12 filters in my station). It's a pain in the *** to do, but well worth it when customers with SUV's comment on how nice it is to fill up & leave in under 5 minutes. I used to have a Tahoe and some stations it took me 20 minutes to fill up 30 gallons.

That said, when a dispenser is well maintained, the pressure from the nozzle can be extremley high, causing a little gasoline to splash up into the little holes around the tip of the nozzle. These holes are meant to vacuum the fumes being pushed out of the vehicle's tank and send them back in to the tanks underground to minimize air pollution. The hoses we use are two-way hoses. One line inside the hose delivers fuel to the car, the other sucks up fumes using an air/vapor pump. When liquid gas is splashed into these holes, the pump sucking the fumes out triggers and stops the flow of gas to the car.

Another problem that causes the dispenser to stop, is an old or damaged nozzle. These things are somewhat sensitive and if they are slightly bent (from being dropped or when some genius drives away with the hose in the tank and the line breaks away) the assembly in the nozzle might get a small drip of gasoline into the holes causing the same to happen. A similiar thing happens with some certain car models that either have kinked fill tubes, or poor designs from the factory. A lot of customers with the new Ford Mustangs & Escapes complain about the dispensors clicking off.

Sorry for the Gas Station 101 course...just thought someone might benefit from this basic knowledge of how a gas dispenser works (by the way, there are no gas pumps above ground...only underground. That's why up top they are now called dispensers, not pumps. When a customer pulls the lever to pump gas, it triggers the pump in the tank underground on and the gas flows under the pavement from the tanks up througt the dispensers & into your car.)

Enough.

-Ian

 

Ah, I always thought that the gas station people could change the flow rate of the dispenser, because I see so much variation in the flow from station to station. Some dispensers allow you to slow the flow rate down quite a bit as you "back off" on the dispenser lever, while it doesn't seem to have any effect on others; it's full blast or nothing.