Usually, the fuel pump relay that keeps on blowing acts as a symptom when there is a fault in the fuel system or electrical parts. The common causes comprise excessive drawing by the fuel pump itself. By design, fuel pumps are driven at 12 volts and use a certain amount of current, usually between 6 to 10 amps. This would be the case if the pump is aging or developing resistance to flow due to either a clogged filter or due to internal wear, in which case it can draw more than what the relay can handle, and it burns out the relay.
Another frequent culprit involves electrical shorts in the wiring. Most short circuits are caused by worn or damaged insulation, which allows a direct path to ground and can give a surge of current that might well blow the relay in short order. In high-mileage vehicles, deterioration may occur over time due to wiring being exposed to engine heat or environmental factors. Mechanically, it is generally recommended that wiring connections for fuel pumps are checked and retained on a regular basis, especially in those vehicles with over 100,000 miles, since older connections have greater chances of causing a short.
Of course, relay quality itself should be considered. Cheap, low-quality relays may not be robust enough to keep maintaining such high current draw for a long period of time, especially for those high-performance and turbocharged vehicles. High-quality relays, capable of manufacturing up to 20 amps, are less susceptible to burnout and more suitable for extreme usage. In that sense, getting a good quality relay would seem like a small investment; generally in the range of $20 to $50, it can actually help avoid frequent failures and increase the life span of the fuel pump system.
A failing fuel pump will also lead to the repeated blowing out of relays. When the pump wears out, it may cause increased resistance and work less efficiently, thereby leading to a higher current draw. Most fuel pumps have a service life of some 100,000 miles; past this mileage, they might start failing, therefore leading to symptoms like stalling, poor acceleration, and frequent failures of the fuel pump relay. Such might be the case where replacing the fuel pump along with the relay is a plausible long-term solution.
As once said by automotive expert Lee Iacocca, “You can have brilliant ideas, but if you can’t get them across, your ideas won’t get you anywhere”. Fixing the problem rather than merely replacing the relays is the key to proper maintenance of the Fuel Pump system. To know more and for quality replacements, visit Fuel Pump.