Can a Fuel Pump Relay Work Intermittently? (Yes, It Certainly Can)

There is a small electrical component called a fuel pump relay to control the current flow to a car’s pump. In general, it is placed inside the car’s fuse box.

This electronic device aims to ensure that the pump gets a sufficient power supply to run smoothly. Excess current flow can cause overheating and can damage the pump’s wiring.

So, protecting the pump from it is also a duty of a fuel pump relay. Dust, debris, and the electrical power rush are the key factors that can directly damage or affect the performance of a pump relay. A fuel pump relay acts as a monitor for the fuel pump.

But, can a fuel pump relay work intermittently?

Yes, a fuel pump relay can work intermittently before completely stopping work. It also gives a proper signal to the car owner that something is seriously wrong and that needs to be taken care of on urgent basis.

It instructs the pump to get active or to turn off, according to the requirements. Can a fuel pump relay work intermittently? Many people wonder about this. Yes, fuel pump relays work intermittently, and we will discuss this topic’s important aspects in this article.

Hope our detailed research on this topic will help you to know the fuel pump relays more closely.

Can a fuel pump relay work intermittently


How do I know if the fuel pump relay is bad?

To do it, park your car at any safe and level place. Turn the car’s key to the on position, but don’t start the vehicle. You may hear a clicking or buzzing sound when you turn the key. Now, come out of the car, open the hood, and look for the fuel pump relay. Now cut the connection between the negative cable and the battery.

How do I know if the fuel pump relay is bad

Now, carefully remove the relay from its position. Now, take a multimeter and switch the knob to resistance mode. The 4 pins of pump relays are for ground, input voltage, load, and battery. Now, connect the multimeter probes to the load and the battery pins to the relay. Now connect a 12-volt power supply to the relay.

You can hear the beep sound if there is no cut in the relay. If you don’t hear it, then the relay is faulty.

Can a fuel pump relay work intermittently? 

The main task of the fuel pump relay is to direct and control the flow of electricity to the fuel pump. So, the pump can be affected if the relay is not working properly. But in some conditions, the relay can still work intermittently after it has gone bad. Some common reasons are: 

  • Coil: If your car is too old, the coil has weakened with time. It can be a cause of the pump not starting properly.
  • Loose terminals: If there is a loose connection among the terminals or loose or worn-out coils, the pump will not work properly and quickly.
  • Contact issues:  Fuel pump relay contacts wear out with time. So the pump can irregularly turn on or off.

As fuel pump relay plays a crucial role in a car’s mechanism. And whenever any crucial part of a car’s mechanism is not in its form, the car can’t start and run properly. Dust, idleness, and electricity surges are the main reasons that can cause a fuel pump relay to not function properly.

Before completely stopping work, the fuel pump relay gives signals. And it is good to replace it at this phase, or else the fuel pump can get damaged, increasing the repair cost. Therefore, the fuel pump may work intermittently for some time, and after that, it gets completely damaged. 

Symptoms of bad fuel pump relay

To identify a faulty fuel pump relay, there are some simple signs. 

Symptoms of bad fuel pump relay
  • Engine stalls: Engine stalling is one of the most common identifications of damaged fuel pump relays. If your car keeps stalling irregularly, you need to understand that the engine is not getting sufficient fuel for the damaged relay.
  • Engine Fail to start: Because of the improper function of the relay, the car’s engine can face difficulties starting. The engine doesn’t receive proper fuel supply due to a faulty relay. 
  • No noise in the fuel pump: In general, the fuel pumps create a clicking or whining noise. This pump relay emits this buzzing sound whenever you switch the car’s key to the on position. But for a faulty fuel pump relay, this noise gets omitted. 
  • Rough acceleration: To the improper supply of fuel, the acceleration of the car suffers. When the engine doesn’t receive proper results, it can’t accelerate smoothly.
  • Car dies suddenly: If a car dies suddenly when running, there is a faulty fuel pump relay.

How does a car act when the fuel pump relay is going out?

The car can’t deliver smooth performance when a fuel pump relay is going out. The engine feels a loss of power while driving. The car can not start smoothly, and the engine starts to stall irregularly.

The fuel efficiency of the car can also decrease drastically. And the car starts to consume comparatively more fuel.

How does a car act when the fuel pump relay is going out

In some extreme cases, the car may produce a loud whining noise. If the fuel pump relay is damaged completely, the car will not start. Whenever you face such indications, checking the fuel pump relay with an experienced mechanic is good.

And if he found it defective, it is good to replace it as early as possible, or it can damage the other costlier parts of the car.

How long does a fuel pump relay last?

The average life of a fuel pump relay lies somewhere between 160,000 km to 300,000 km. So if you are using the vehicle regularly, then the average lifespan of the fuel pump relay will be 8 to 9 years. And if the car is used occasionally, it can last 15 years.

Can a bad fuel pump relay cause misfire?

The answer is yes. When there is a defective fuel pump relay in the car, the chances of engine misfires and problems with the ignition system are very high. Engine misfires result in idling or stalling.

Can a bad fuel pump relay drain the battery?

If you notice that your car’s battery is draining too quickly or it gets drained suddenly, please check the fuel pump relay once. One of the most common reasons is that the car’s fuel pump is running full-time. It is the relay’s responsibility to cut the power when needed. If there is any fault in this relay, then this can happen.

Can you bypass a fuel pump relay?

Yes, you will get a specific switch to bypass the fuel pump relay in some vehicles. Doing so will give direct control over the fuel pump circuit. Consequently, fuel consumption will increase rapidly.

Can you bypass a fuel pump relay

And in some cases, the engine of the car can be damaged. So it is not recommended to bypass the fuel pump relay. If you have found the relay is defective, then it is good to replace it instead of skipping it. 

Frequently Asked Questions (FAQs)

Do fuel pump relays often fail?

Age and minor electrical short circuits are the main two points that cause serious damage to the fuel pump release relays. If your car is 8 or 9 years old, checking the relay from time to time is good to skip any easy situation in the middle of the road. If you have a new one, you don’t have to worry about it; you will not face any issues. 

Can a fuel pump relay be bad and still work?

Yes, a fuel pump relay doesn’t immediately stop working. When it is not in its best condition, it starts to give you a lot of signals (which we have mentioned above in this article). For some time, it will run in this condition, then it will stop working. So, whenever you get those signals, you need to change them or consult an experienced mechanic.


The fuel pump relay is vital to a car engine’s mechanism. This small electrical part controls the engine’s power supply. If it is defective, then the engine of the car directly suffers.

As a result, you will face a lot of problems while driving. It can work intermittently, but if you face any problem, it is good to check the condition of the relay.

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