filling gas

Scott

"Terminator13" wrote

There isn't any on-car sensor that tells the pump when the tank is full.

The next time you fill up, take a look at the underside of the spout. You'll see a small hole that connects to a tiny plastic tube that runs up the inside of the spout to the handle/valve assembly. The normal flow of fuel sucks a small amount of air up the tube and through the valve mechanism, where it does nothing. When the tank is getting full, fuel bubbling up from the tank blocks the hole, creating a small vacuum that triggers the shutoff inside the handle.

Abnormal shutoffs can be cause by a defective nozzle, the little plastic tube disconnected, dented (metal) or pinched (rubber) fuel inlet pipe to tank, inlet "flapper" broken off and stuck part way down the inlet pipe, bad design (I've seen pickups where the gas actually has to "uphill" before making it to the tank), and assorted other things.

Try pulling the nozzle out a bit, or rotating the handle left or right to get the fuel to flow smoothly down the pipe. Or just pump slower, but not TOO slow, or there won't be enough vacuum created to trigger the shutoff, and you 'll be complaining that you keep spilling gas on your shoes.

I have the same problem with my two Grand Marquises. As far as I can tell, the vapor recovery crap on the dispensing nozzle is nonfunctional and the vapors in the tank and filler tube are being compressed by the incoming gasoline rather than being removed by the vapor recovery crap. Considering that as a result all the vapors are being released into the atmosphere anyway, I have no problem putting the nozzle only half way into the filler tube so the rubber boot doesn't seal against the filler tube neck; that prevents the vapor pressure from setting off the check valve mechanism and lets the tank fill, while the check valve can work just fine when the pressure actually rises because the tank is full.

Now, that oughta start the argument of the century. :)

Some of those gas pump nozzels are kind of tricky.They keep cutting off when I am putting gas in the tank.I don't think the gas supplier people (or whomever supplies the pump nozzels) maintain the gas pump nozzels properly. cuhulin