Under normal operating conditions a fuel pump will not draw a fuel tank down, as it provides fuel to the engine only at a rate which the engine demands. On the other hand, a problem with the fuel system, such as a leak or a malfunctioning return valve, can give the impression that the tank is emptying faster than usual. Typical fuel pumps are designed to flow at rates of 150-200 liters per hour for regular cars, which is more than enough to meet the fuel flow demands of an engine without having to excess amount of fuel being pumped into the flow.
A defective relay or wiring can also keep this relay open causing the pump to run even without the engine running which could ultimately empty the fuel tank. Very occasionally, though, this happens due to an electrical fault that causes the pump motor to stay on. If your fuel consumption seems excessive, the relay and wiring are the first to check, if a relay is damaged, then when replacing it, the wrong relay can cause continuous flowing, and it may be better to drain the fuel tank to avoid this phenomenon, automotive experts recommended.
Do bear in mind that these high capacity fuel pumps are sometimes rated at over 300 liters per hour and may also quickly empty the tank should the engine’s hunger for fuel be significantly higher than that of a racing or modified vehicle. The pump is designed so it can output this higher specification but the actual use rate is dictated by the engine not the pump. Fuel-efficient driving habits and regular maintenance control fuel consumption, since aggressive driving and high RPMs can raise consumption by as much as 30 percent that leads to tank emptying faster.
Regular checking of the Fuel Pump and components (like seals, and hoses) means that leaks or failures that lead to extra drainage of fuel can not occur. To avoid these possible scenarios will make sure the fuel consumption is done right, and that may not create the sense that the this is the fuel pump that is sucking the tank.