What Is the Role of a Fuel Pump Relay?

The fuel pump relay controls the electrical supply to the fuel pump; it functions as an electronic switch that will only allow your car to start and remain running if and ONLY (!) when, conditions are correct for the engine to fire up. The role of this relay is to use signals from the ECU to determine if it activates/ deactivates fuel pump as per engine status. When the ignition is switched on, the relay provides power to the fuel pump for a few seconds in order to pressurize the fuel lines, which normally amounts at typical pressures of 30 to 60 lbs per square inch (psi) in most cars. This pressurization is necessary for proper fuel injection and also to start smoothly.

While the engine is running, power continues to flow with the relay open, so that the fuel pump can provide a constant deliverance of fuel. The relay allows the ECU to control the pump without having to switch high electrical currents through the ignition key switch, thus preventing wiring from overloading and lessening wear on the ignition system. In addition the relay gives a measure of safety; if the engine quits running or is shut off, power to the fuel pump will be cut by the relay with less chance of creating conditions for fires or other hazards.

If the fuel pump relay is failing, then you will likely start to have hard starts, the engine may suddenly cut off while driving and your power loss might come and go. Vehicles run on 12-volt electrical current, and most of the time when a fuel pump fails to operate, it is because of inadequate power due to a bad relay. This can lead to misfires in your engine or losing power completely. Relays Relay issues, according to automotive experts we talked to, are one of the most common causes for fuel system failures—responsible for perhaps 1-in-10 pump-related malfunctions on high-mileage vehicles.

At around $20-$50 a replacement fuel pump relay costs significantly less... plus can save the owner expensive engine modifications associated with low fuel delivery. Reliable fuel pump operation is maintained resulting in optimal engine performance, increased fuel economy, and enhanced safety due to proper relay functionality. For more information on fuel pumps systems and maintenance, please visit Fuel Pump.