A hesitation during acceleration with a bad fuel pump is caused by an inability of the fuel pump to provide the required amount of fuel to the engine at the needed pressure. Most vehicles’ fuel pumps operate within a range of 40 to 60 psi, and any drop in pressure below that can cause hesitation or stalling. A faulty fuel pump can cause erratic fuel delivery, especially when the engine requires more fuel during acceleration, like when joining highways or climbing steep inclines. In a study by Automotive Repair Network, almost 15% of vehicle performance problems in hesitation and stalling result from a malfunctioning fuel pump or its components.
The fuel pumps fail either by wearing out the internal components or by losing the efficiency of the electric motor driving the pump. Some of the common symptoms of a bad fuel pump are inconsistent fuel pressure that could cause delays in fuel reaching the engine. In fact, 20% of vehicle acceleration hesitation issues were directly related to low fuel pressure caused by a malfunctioning fuel pump, according to AAA’s 2020 vehicle diagnosis report. It is on this consistent flow of fuel that the fuel injectors of the engine depend, and if they do not get the required amount, the air-fuel mixture becomes lean, thus causing hesitation or a complete stall.
For example, Ford Motor Company reported that a set of complaints from owners of certain models showed hesitation to accelerate due to fuel pump failure. These failures were traced back to damaged impellers in the fuel pump, which caused the pump to fail at higher speeds, preventing the engine from getting enough fuel. The issue became especially noticeable during rapid acceleration, as the fuel system struggled to meet the demands of the engine’s throttle.
Bad fuel pump symptoms include rough idling, a loss of power, and marked hesitation or stalling when acceleration demands are made. Because of an inability of the fuel pump to supply proper pressure to the fuel, maintaining engine power during such high demands is quite challenging. In 2021, Bosch Automotive issued a study indicating that 18% of all fuel system failures were tied directly to malfunctioning fuel pumps and usually led to hesitation, among other performance-related problems.
One of the main indicators of a bad fuel pump is a pronounced hesitation upon depressing the accelerator, according to Sarah Jensen, an automotive expert. The reason behind this is simply because the engine does not receive the adequate amount of fuel flow required by such sudden demand in acceleration. If left unaddressed, these problems will further deteriorate into serious issues such as misfires or a complete shutdown of the engine, since the air-fuel mixture keeps being compromised.
Replacing a faulty fuel pump can restore the proper fuel pressure and resolve acceleration hesitation. In many cases, a fuel pump replacement can cost anywhere from $300 to $800, depending on the make and model of the vehicle. If you feel that a bad fuel pump is the cause of hesitation, then it is high time to take immediate action; otherwise, it may result in further damage to the engine. For high-quality fuel pumps, visit Fuel Pump for reliable parts to get your vehicle’s performance back.