Gas pump shutoff annoyance....

[stmcknig]

Hi guys - hope someone might have an idea on this one. I thought our local gas station had set their shutoff on a hair trigger but I've noticed others very similar. No matter which way I angle the nozzle, I have to virtually trickle the stuff in, even if the tank is pretty much empty. I don't recall having to be this careful when I bought the car in '04 but it's really starting to wind me up. Is there a breather pipe or something which may be causing too much back pressure in the tank to shut the pump nozzle off?

Appreciate any clues :-)

[xzone909]

I have a similar problem when I pump my dad's clk 500. I just have to stand there the whole time and hold the nozzle 1 inch or so further out than normal and it shuts off when the tank is full. Watch out though might not shut off when you do it.

[...Mark...]

Here's how the pumps work. http://www.wonderquest.com/sleeping-...-hospitals.htm

If i had to guess it was a problem w/ the vacum on the pump.

Do you tend to go to the same stations or do you mix it up? If so is it the same issue no matter what?

[va-terps4]

I'm pretty sure there is a one-way valve in the top of your gas tank that lets air out as the tank fills. It is typically designed to stay closed if the car flips over to make sure gasoline doesn't leak from the car. I've had two cars where this thing would stick and not let air out. Gas station pumps detect the back pressure that results and cut off early. The trick is to get your dealership to experience it. After several trips to the shop, they couldn't duplicate the issue. We finally realized that they were filling the car with a private gas pump setup that doesn't have a cutoff system. Make them fill it at a regular gas station. It is not an uncommon problem and it runs across many makes and models.