The faulty fuel pump means great loss of power, as it is not able to supply the required amount of fuel to the engine for its smooth and sufficient running. Basically, the job of a fuel pump is to keep the fuel flow constant and at the right pressure, which is between 40 and 60 PSI for most cars using a normal type of fuel. When the Fuel Pump begins to fail, it may be unable to pump enough fuel to meet the requirements of the engine when the latter needs more fuel, such as during acceleration or under any load. Symptoms that could be noticed at this point include slow acceleration, loss of power, or even complete engine stalling.
Another major problem that may arise with a failing Fuel Pump is fuel starvation. For an incorrect quantity of fuel, the air-fuel mixture becomes lean, or in other words, the engine runs with more air than fuel in the mixture. Running lean knocks off some power; worse still, this overheats the engine and may be catastrophic over time. In performance cars, fuel flow is very important; a diminished supply will not enable the engine to achieve full throttle horsepower.
A very relevant example is that of the Toyota fuel pump recall, which, in 2019, involved over 700,000 vehicles. Many of the drivers faced power losses and experienced stalling due to malfunctioning fuel pumps. These fuel pumps were not able to maintain adequate pressure for proper fuel flow, resulting in poor engine performance, especially when driving at high speeds or experiencing sudden acceleration.
When acceleration becomes labored, or power is lost when the engine is under stress, it can be a sure sign that something is wrong with the Fuel Pump. If this happens in a high-performance situation, such as with race cars or modified engines, the results of a malfunctioning Fuel Pump can be even more dramatic. This might include something like the Walbro 450 LPH fuel pump-one that is commonly found in performance vehicles-designed to handle and support engines with up to 700 horsepower. If an in-tank pump cannot deliver an adequate volume of fuel, the engine’s power is reduced by upwards of 30%, thus limiting its possible performance. “An engine is no more powerful than the fuel system feeding it,” said David Vizard, one of the most popular running voices in the automotive field. When the Fuel Pump cannot keep up with the demands of the engine, the vehicle will lose power, run inefficently, and probably have its internal parts damaged.
For more information on testing, replacing or upgrading your Fuel Pump see Fuel Pump.