Fuel pump pressure demonstrates a number of easily identifiable symptoms, which can often be observed when driving or even cranking the car. One of the most common signs of low pressure of the Fuel Pump is an engine sputtering-especially on uphill drives or at any moment of acceleration-since the pump is unable to provide adequate pressure to meet higher demands. For most vehicles, proper pressure will fall between 40-60 PSI, and anything less will be felt through noticeable loss in power and performance.
Other symptoms include hard starting where the fuel pump is unable to maintain adequate pressure within the fuel line. This tends to delay the ignition of the vehicle. Mechanics argue that many vehicles whose pumps deliver less than 30 PSI, this results in hard starts since the fuel delivery system takes some more time before it sets its pressure up and starts.
Fuel pump pressure problems also have incorrect fuel economy associated with them. When the pressure becomes inconsistent, the engine runs lean-in other words, incomplete combustion and reduced mileage. For example, a 5 PSI drop in fuel pressure can reduce fuel economy by about 10%.
Another symptom is an irregular idle speed. The engine could idle rough and may even stall. Low or pulsating pressure in the fuel pump breaks down a smooth flow of fuel that an engine needs for a good quality idle. This usually occurs in high mileage, over 100,000 miles, in automobiles because internal pump components could be worn out.
Finally, excessive noise in the area of the fuel tank can indicate problems of pressure, especially when it sounds noisier than usual. A fuel pump that struggles makes a whining noise, which justifies it working harder than designed to do, and this usually points back to low pressure inside or obstruction within the fuel line.
These signs of pressure not only ensure good performance from the fuel pump but also contribute to maintaining the efficiency of the vehicle while preventing more serious fuel system issues from arising.