Voltage to the Fuel Pump is a critical issue in ensuring that optimum performance and functionality of the fuel delivery system in cars perform accordingly. Most automotive fuel pumps are designed to run at approximately 12 to 14 volts while the engine is on, which is enough to hold pressures and flow rates necessary for proper engine performance. The Fuel Pump may draw less voltage when the vehicle is off, but proper voltage needs to be maintained for the system so that there isn't any problem in starting or its operation.
If the voltage drops well below 12 volts, the Fuel Pump cannot operate as it should-to deliver fuel properly. Symptoms of poor performance include stalling or misfiring, or it may not start at all. In one test, it was found that with as little as a 1 volt drop, the fuel flow rate could be lowered up to 10%, which grossly impacts the performance and efficiency of the engine.
Poor wiring connections or a failing fuel pump relay are other sets of electrical issues that can cause voltage fluctuations, hence affecting fuel delivery inconsistency. For example, if the Fuel Pump voltages drop due to a failing relay, then the fuel pressure may fall below the recommended operating range of 30 to 80 psi and cause engine performance problems. This was imminent in the 2019 recall made by Toyota, where faulty wiring in the Fuel Pump allowed the pump to receive insufficient voltage; thus, stalling the engine.
These are simple ways of preventing Fuel Pump voltage problems, but these regular tune-ups require attention to such minor details. Most fuel pump relays are pretty cheap, ranging from $20 to $50, to replace compared to the cost of replacement for a Fuel Pump, which may range in the area of $400 to $800.
As Henry Ford, the great pioneer of automobiles, once said, "Failure is simply the opportunity to begin again, this time more intelligently." A proper understanding of the voltage requirements of the Fuel Pump and keeping the electrical system in order will help avoid failures and make the vehicle run smoother.
For further detailed information on Fuel Pump voltage requirements and diagnostics, refer to Fuel Pump.