What Causes Fuel Pump Relay Burnouts?

The reasons for the burning out of fuel pump relays are electrical overload, poor connections, excessive heat, and prolong operation. These relays manage the amount of power given to the fuel pump supplying the 12-14 volts required for proper fuel flow and pressure. The relay, when burnt out interrupts this power supply which may lead to a stalling, hard starts, or a failure of the entire fuel pump. When it comes to relay burnouts electrical overload is the most common reason because this happens when the fuel pump passes more current than the relay can handle. The relay is a standard relay that can handle about 15-20 amps but if the pump is stalled (might be the condition required to draw much more singnal) or the internal is worn causing high current the relay gets hot and burns.

Relay burnouts are also due to poor electrical connections and corroded wiring. The resistance generated by corroded or loose connections means the relay will have to exert itself more than usual to hold a connection steady, with the result being excess heat. That heat accumulates in the relay, and total contact degradation occurs and then burns out. Twenty percent of older vehicles’ fuel systems are impacted with relay burnouts due to corrosion, especially in vehicles over ten years old or in humid climates, mechanics have found.

Heat is another big culprit. In most applications, relays are positioned in the engine bay, an area that can easily exceed 200°F – particularly when the vehicle is experiencing our most punishing load conditions. The high temperatures can lead to the internal parts of the relay to expand, which then slowly breaks down the electrical contact points. In fact, research has shown that increased ambient temperatures can cut relay life by as much as 30%. This risk can be minimized by either installing the relays in an area with sufficient ventilation or by using heat tolerant relays.

Relays also can wear out just by age and using them over and over again. The contacts open and close thousands of times as a relay operates, and after many thousands of cycles the contacts become worn. The components in a fuel pump relay are used to wear over time, and over 100k miles on a vehicle is when they are most likely to burn out, especially in high-mileage vehicles.

There’s something noted automotive expert Ed China said before, that if you think of how a car works, there are small components such as relays that carry the load. The only salient point he made in this regard, which I think also indirectly accentuates the importance of relays in our quest to ensure steady fuel supply, is mentioned below.

Opting for a well built Fuel Pump whose relay assembly is robustly designed to cope with the natural up and down movements of current and temperature will lead to a more suitable relay which will help eliminate the possibility of a burning relay, and therefore create a stable fuel system.

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