A fuel pump relay problem may be manifested through several symptoms, and its diagnosis is based on the look for common signs such as erratic operation of the fuel pump or no fuel delivery at all. For example, a no-start Chevrolet Impala may have a malfunctioning fuel pump relay even when the fuel pump and filter are in good condition. That would be due to a malfunctioned relay that blocks power from reaching the pump.
One can determine whether a fuel pump relay problem really exists by listening for the normal hum of the fuel pump when the ignition is turned to the "ON" position. At most, when it is time, there is usually the sound, something like low humming for around 2 seconds every time the key is taken to the "ON" position when power should reach the pump to turn on. With that said, if no sound occurs, then typically that is due to issues on the part of the relay and will not feed power into a fuel pump for the pressing purpose and transport of the fuel from the tank upwards toward the engine.
Speaking from a data point of view, research has estimated that the failure of the fuel pump relay contributes to about 25-30% of all fuel system-related problems in vehicles older than 10 years. This percentage increases in high-mileage vehicles, especially those with over 150,000 miles, as the relay's electrical components wear out. According to a study done by the National Institute for Automotive Service Excellence, a faulty relay can lower the efficiency of the fuel system, causing intermittent engine stalling, especially under heavy acceleration or after the engine has been allowed to run for extended periods.
As for instance, in the Toyota Camry, stalling when started but continuing to work again after several minutes shows there might be a malfunction of the fuel pump relay supplying power in a discontinuous mode to the fuel pump. An intermittent operation of such a relay could cause transitory losses in fuel pressure and therefore stall or hesitate on acceleration. Starting issues can also be attributed to faulty relays, especially if it cannot deliver the electrical signal needed by the pump for actuation at startup.
The other diagnostic test is the checking of the relay itself. The fuel pump relay is generally located in the fuse box or near the engine compartment. It can be visually inspected for wear, such as corrosion or a burnout on the components. For example, owners of Ford F-150 may experience that damage to the relay terminal would prevent the fuel pump from powering up, especially in cases when the truck faces extreme temperatures or fluctuating voltage levels.
The voltage across the relay terminals can also be measured using a multimeter for the purpose of confirming whether power is actually being fed to the fuel pump. It is normally set at 12 volts, but anything less may mean the failure of the relay. Some relays may intermittently fail to provide power; these are more trickier to identify, but again, jumping the relay by directly connecting can help identify the problem. If the fuel pump operates with a jumper but not with the relay in place, it’s clear that the relay is the issue.
The cost of replacing a faulty fuel pump relay typically ranges from $50 to $200, depending on the vehicle model, but addressing the issue early can prevent more costly repairs related to fuel pump damage caused by intermittent power supply.
For correct identification and replacement of a fuel pump relay, coupled with good diagnosis advice, visit Fuel Pump for expert guidance.