Many things wrench, and all have a corresponding effect on the performance of the system and its own durability. Perhaps the most common cause is a fuel pressure regulator going bad—given that its job is to keep levels consistent within the fuel line. As a regulator goes bad, fuel pressure may rise and fall with engine acceleration causing problems in various driving modes. For the most common, a run-of-the-mill fuel pressure regulator will set the pressure somewhere between 40 and 60 psi or bar, as they like to say in Europe, depending on your make. This can both create stalling or bad idling if this range is not maintained.
Clogged fuel filters can also cause irregular pressure. Fuel filter contaminants accumulated over time, causing fuel to be brought into the tank and block pump flow That can cause the drops in pressure to be more scattered. In the most severe of cases diminished fuel flow can result in a 25% reduction, which is going to greatly hamper engine performance up top (potentially misfiring or hesitating under acceleration). For instance, a clogged fuel filter may allow only half the amount of fuel needed to keep the engine running perfectly well, especially during intense load conditions.
The fuel pumps aging and going bad themselves is another major contributor. The life expectancy of a fuel pump is around 100,000 miles. Over time this ability to keep a near constant pressure drops off — especially under heavy duress like high-speed driving or towing. A fluctuating pressure from a fuel pump results in less fuel efficiency and the engine can run less efficient as well. One high-profile example of this problem was the massive recalls carried out by several carmakers in the early 2000s following reports of erratic fuel pump pressure induced by failed components.
Fluctuating Fuel Pump Pressure Due to Electrical Issues A number of electrical issues might also cause fuel pump pressures to change. If the relay is faulty or the wires have corroded, then you will not be getting a consistent electrical supply to the pump and erratic pressure is often found. The power of the fuel pump could be reduced by around 10-15 percent thanks to an electrical short, which may prevent the fuel from being delivered as quickly and result in momentary loss of power during hard acceleration.
Excessive heat can also hurt fuel pump performance. A: The fuel pump can overheat if the vehicle is run for long periods or if operated in high temperature surroundings. The gasoline in the tank helps to cool the pump, and when this is evaporated or nearly gone from your tank, this heating develops. If there is not enough fuel however it may result in the pump overheating and thus causing pressure irregularities. Results of the tests have shown that when a pump gets overheated it loses as much as 20% of its efficiency, particularly during demanding driving situations.
So, in the end all of this causes fuel pump pressure to slide around and each one of these needs a fix. Fuel pumps are one of the most important parts to keeping a motor running properly, as having the correct fuel pressure is essential for optimal engine operation. In the event of any deviation, it is important to deal with culprit quickly so as not to cause any harm long term damage to your cars engine and fuel system components. Visit Fuel Pump for more information on Maintaining a Fuel Pump.