Fuel pumps feed fuel to engine carburetors by pumping it from fuel tanks. Removing fuel leads to a vacuum that, in any other case released or maintained with the correct pressure, becomes too great, causes pump failure and starves the carburetor of fuel. Until this vacuum is released, the vehicle will not likely run.
Things to do for stopping the situation
Most gas caps have valves fitted that automatically release the vacuum at optimum pressure. Detaching the cap enables the auto to jog, however solution should not be any long-term fix. In case the cap has a faulty valve, replace the cap. Alternatively, some cars have a breather pipe fitted. If this pipe becomes blocked, clear or change it out. Being a temporary fix, remove and immediately refit the cap to discharge the vacuum.
An older-type gas cap without the need of bodywork cover
Detaching the cap prevents an army tank vacuum, stops the car from stalling and stops pump malfunction. Nonetheless it adds to the chance of fuel vapor contamination, pump blockages, increased consumption, poorer performance and fire hazard. These risks are increased greatly when the cap doesn’t have bodywork cover.
Will not insert a rag on view gas tank filler pipe to prevent spillage and evaporation. This greatly increases fire danger.