If the fuel pump is weak or faulty then car will hard to start because it supplies fuel into engine. Most vehicles need the fuel pump to spit out 40-60 psi or more just in order for there to be enough pressure getting into the injectors. If the pump can not hold this pressure, the engine will be starved of fuel and then you may have longer crank times or worst case NO start. Experts say that fuel pumps running below necessary pressure can add, on average, up to 30 seconds of starting time and ultimate frustration leading to the destruction of battery life because pushing pump turns over for so long a duration.
Fuel pump problems are only to get more apparent in colder regions. As the mercury falls, fuel will undergo a certain degree of gelling which makes it harder for the pump to achieve the proper flow. The extra load makes the pump even less efficient if it is already bad and can lead sometimes to not starting at all. That helps its fuel pump keep a steady discharge pressure and prevent cold start problems, technicians say you should never get below one-quarter of a tank when the weather gets frosty. Cars with fuel pumps that are more than five years old, or those driven many miles to the point of wear and tear, tend to have difficulty starting at a higher rate because parts just can't make pressure as well (or even work entirely).
Other symptoms such as sputtering, and difficulty to start the car when parked for prolonged periods of time are classic signs that your fuel pump is dying. The fuel pump itself can fail, too — because the relay controls electrical flow to the pump, a bum kill switch will prevent it from running when you turn on your ignition. A failing relay typically runs less than $50, peanuts compared to the cost of a total fuel pump failure that might hit well over $500 once you factor in labor for models still under warranty.
Or to quote legendary auto engineer Carroll Shelby, "Your car is only as good as its weakest link. This little nugget of advice should remind you just how important Fuel Pumps can be in terms of good starts and reliable motooring. Keeping a Fuel Pump that works right stops hard starting conditions, prolongs the life of your battery and encourages reliability keeping both you vehicle running long enough to see better days as well making sure the driver/driverette doesn't have cracks in their face from anxiety.