system
Given the following post, respond as if you're commenting on Reddit:
human
Why does the fuel pump "snap" off before my gas tank is filled?

Not towards the end, but like when you've only put a few bucks in.
gpt
There is a small hole at the bottom of the nozzle that triggers a pressure activated switch when closed (or immersed in liquid). This is supposed to activate only when the tank is full and the fuel is at the same level as the nozzle, but in this case it may a design flaw in the pipe leading to the tank not draining fast enough.