Fuel Pump Failure Signs and Replacement Timing Explained

A fuel system issue is often the first thing that many users anticipate when a heavy equipment engine stops while driving or abruptly fails to start. The system as a whole depends heavily on the fuel pump and fuel pump relay. Defective fuel pumps and fuel pump relays are sometimes hard to find right away. MyMROmarts will provide you with information in this post on whether the fuel pump relay can operate intermittently, how to spot mechanical fuel pump failure, and when to replace the fuel pump so you can properly diagnose the issue and take the necessary action.

 

Can a Fuel Pump Relay Work Intermittently?

One crucial component that regulates the fuel pump's beginning and stopping is the fuel pump relay. By turning the current on or off, it enables the fuel pump to operate. A common query from users is if the fuel pump relay can operate sporadically.

 

Relays for fuel pumps are not made to operate sporadically. The diesel fuel pumps will not be able to continuously feed fuel if the relay malfunctions or is not operating correctly. The engine will operate unpredictably as a result. Poor relay contact or broken internal components are typically the cause of intermittent functioning. You should get the fuel pump relay examined and replaced right away if you observe that it is operating strangely.

 

Signs of a Bad Mechanical Fuel Pump

A mechanical fuel pump is a common type of fuel pump found in many heavy equipment. It delivers fuel from the tank to the engine by mechanical actuation. Designed to be rugged and durable, they are subject to a number of failures as they are used over time.

 

1. Difficulty Starting the Engine

When the fuel pump malfunctions, it can result in fuel not being supplied to the engine properly. At this point, the engine starts with repeated attempts, or it may not start at all.

 

2. Weak Engine Acceleration

When the mechanical fuel pump fails to provide a steady flow of fuel, the engine's acceleration performance will be affected. During the driving process, you will find that the acceleration response is slow or suddenly lose power.

 

3. Abnormal Fuel Pump Noise

Under normal circumstances, the fuel pump should work smoothly without any noticeable noise. When the fuel pump is malfunctioning, you will hear a humming sound or a strange noise. This is usually a sign that the internal parts of the fuel pump are damaged.

 

4. Engine Stalling or Instability

If the fuel pump is unable to supply fuel consistently, the engine will stall while driving. Sometimes the engine will also have unstable speed and shaking phenomenon.

 

5. Low Fuel Pressure

Fuel pump failure can also lead to insufficient fuel pressure. This is mainly manifested by the

engine running with insufficient power and inaccurate fuel gauge readings.

 

Bad Mechanical Fuel Pump Symptoms

In addition to the above-mentioned signs of failure, the following symptoms are also indicative of mechanical fuel pump failure.

1. Increased Fuel Consumption

When the fuel pump is not working properly, it can also lead to a decrease in fuel combustion efficiency, resulting in higher fuel consumption.

2. Poor Engine Operation

When the mechanical fuel pump is unable to supply oil stably, it will also cause the engine to work unstably at low speed or idle speed.

3. Abnormal Emissions

Fuel pump failure will lead to incomplete combustion of the engine, and ultimately make emissions abnormal. The main manifestation is black smoke or increased exhaust gas concentration.

 

When to Replace Fuel Pump?

The fuel pump is a wear-and-tear component. As it is used over time, its performance will gradually deteriorate. Once there are obvious signs of failure, you should consider replacing the fuel pump.

 

1. Vehicles Fail to Start for Long Periods of Time

If the fuel pump fails, heavy equipment will often fail to start properly, especially after long periods of parking. If the fuel pump is confirmed to be the problem, replace it as soon as possible to avoid engine damage.

 

2. Engine Overheating

When the fuel pump is not working properly, the engine will overheat due to lack of fuel. This situation can lead to more serious damage to heavy equipment if the fuel pump is not replaced in time.

 

3. Unresponsive Acceleration or Loss of Power

If you notice that your vehicle has a sluggish acceleration response or a loss of power when accelerating. It is likely that the fuel pump is faulty and needs to be replaced.

 

4. Abnormal Noise

If the fuel pump makes an abnormal noise during operation, it is an obvious warning sign. The fuel pump should be checked and replaced as soon as possible.

 

5. Insufficient Fuel Pressure

If the fuel pump is found to be unable to provide sufficient fuel pressure through diagnosis. When the engine does not work properly, it means that the function of the fuel pump has been seriously reduced.