The answer is yes, a fuel pump relay can certainly fail but not gradually — the cause is usually some sort of electrical spike, overheating or just regular wear and tear. Relays help stabilize the 12v — 14v that hits the fuel pump so it retains a consistent amount of fuel pressure (and flow). A relay that unexpectedly breaks down will cut the power supply of a fuel pump, and of course, the fuel supply will also quickly be interrupted. This may cause the engine to stall; hard starting, or poor starting, or inability to start at all. Relay failure is sudden and it can leave the driver stranded without beforehand warning, which is why knowing what causes this sudden breakdown is a necessity.
Of all the reasons that cause relays to fail, electrical issues are by far the most widespread. The internal contacts of the relay can become corroded or worn over time, causing connections to become weak and prone to intermittent operation. This is more common in older vehicles or vehicles that have been subject to humid or corrosive environments. Research from the automotive maintenance field has indicated perhaps a 20% increased likelihood for sudden relay failure due to electrical corrosion in relays found in a vehicle older than 10 years old. Checking the relay and associated wiring on a regular basis can detect problems early, allowing you to assure that the fuel system is still functional.
Another significant threat to relay function is overheating. Fuel pump relays have tiny coils and contacts that normally get hot while they do their job, but are not designed to endure the heat for long. The relay can overheat in an engine bay exceeding 200°F, causing the internal contacts to expand and fail long before the relay is rated to fail. Indeed, research reveals that a rise in temperature may decrease relay life by as much as 40%. Cooling and insulation are vital for long-term reliability in relays installed in tight or poorly ventilated spaces, which are especially susceptible to overheating.
Not all sudden relay failure is without warning. Sounds of clicking from the relay zone, intermittent stalling of the engine, and a starting delay may also be signs of a weak relay that is having a hard time staying on. As automotive expert and television host Ed China once explained, “Relay failure is an invisible problem until the day it leaves you stranded,” highlighting the importance of replacing relays at the first indication of a problem.
Where a high-quality Fuel Pump and Fuel Pump Relay System are concerned, for best reliability of the rest of the fuel system. These components can handle changes in voltage and temperature to deliver reliable fuel supply whilst offering the increased safety of not forgetting about sudden relay breakage, resulting in a faster and smoother drive.