Hard starting is certainly an issue with the fuel pump. The fuel pump is responsible for transporting fuel from the tank to the engine at adequate pressure and flow volume. If the pump malfunctions and does not provide an adequate amount of fuel or pressure, the engine might be difficult to start. Gas engines can range from 35 to 65 psi, but diesel fuel pressures hover around or above the 1,500-psi mark. As the pump continues to run and is not able to sustain this pressure, fuel flow to the injectors will become insufficient, causing excessive crank times or a no start condition.
Fuel pumps can and do fail due to the effects of age, contamination from rust or other issues in your fuel tank, as a breach of electrical continuity and more. New standards and modern fuel pumps mean that these components last for 100,000 to 150,000 miles in a standard vehicle, but bad gasoline or disregarding regular maintenance will reduce this lifespan. In a report from 2021 — here it is mentioned that fuel pump problem was among the most common causes for hard starting, accounting for 15% of all stuck starters.
Low fuel pressure is a sign of failing fuel pump. When the pressure drops below a manufacturer recommended threshold, there will not be an adequate supply of fuel for starting which may require numerous attempts before the engine starts. In addition, vapor lock or a faulty fuel pump relay can prevent fuel from reaching the combustion chamber, leading to the same symptoms.
Two years before that, a recall on Ford models necessitated replacement fuel pumps because they caused hard starting and stalling problems. This example illustrates just how important a role the fuel pump plays in ensuring the engine continues running well.
Speaking with Elon Musk about vehicle component complexity and how overengineering exists in every single part because "performance and efficiency are turnqualities of physics," including the fuel pump A failing pump interrupts this critical balance, causing a decrease in performance and added strain on the motor.
One common method of troubleshooting hard starting due to what appears to be a fuel pump issue with the result is, many mechanics will test the fuel pressure using a fuel pressure gauge. If the pressure is low this confirms that the pump isn't operating properly and replacing the fuel pump might be in order.
To read more about fuel pump diagnosis and repair, go to Fuel Pump for information on repairs/removals and replacement options.