Can a fuel pump relay work intermittently? Here’s how to know

A fuel pump relay is an electronic device similar to an automotive fuse that directs current to the electric fuel pump to ensure that it receives sufficient power to operate smoothly, but not too much power to damage the pump.

The fuel pump requires power to function but too much power can cause overheating of the wiring system without the help of a relay.

The relay is a small black plastic box device if found under the vehicle’s hood and it is usually attached to the firewall. It acts as a monitor and activates the fuel pump when the ignition is turned on and turns off when the car is turned off.

However, just like any other device in the vehicle, the fuel pump relay can be faulty and thus cause the vehicle not to start. So, the big question is: Can the fuel pump work intermittently? Continue reading to find out.

Can a fuel pump real work intermittently?

A simple answer is YES, the fuel pump relay can work intermittently. As pointed out earlier, the fuel pump relay directs current to the fuel pump. So, if, anything happens to it, the fuel pump will also be affected, meaning the car will not start.

When any component that makes the car’s combustion system is damaged, it will also affect other systems in the car. This means that your car will not function.

Some of the things that can make your fuel pump not function properly include dust, idleness, and electricity surges among many others.

For instance, if your car stays idle for a long time, the accumulation of dust may compromise the normal functioning of the fuel pump relay.

In most cases, the fuel pump relay usually gives signs before it goes bad completely. So, if you start seeing signs of a faulty fuel pump relay, you should take action immediately to prevent further damage that can be costly to fix.

So, the fuel pump can work intermittently but only for a while. The best solution is to fix the problem before it causes more damage.

Symptoms of a bad fuel pump relay

Many signs may indicate that your pump relay is really bad. In this section, we will discuss common symptoms of a damaged fuel pump relay.

Engine stalls

One of the signs that show there is something wrong with your fuel pump relay is if the engine keeps stalling. If the car engine keeps stalling, then that is a sign that fuel is not being pumped into the engine.

“Check engine” light warning

If there is a problem with the combustion system of your car, then a “check engine” warning will pop up on the dashboard. If you do a follow-up, you may find out that the problem is a result of a faulty fuel pump relay.

The engine taking too long to start

When the engine is taking too long to start, then it means that the engine does not get sufficient fuel to start properly.

No noise when starting

If you don’t hear the normal noise when the car is starting, then it means that there is something wrong with the fuel pump.

Rough acceleration

If the fuel pump is not operating efficiently, your car acceleration will be affected. Just like the human heart runs on oxygen and blood, the car engine runs on fuel and if it is not pumped in the right amount as required, then your acceleration will be affected.

The car dies while driving

If your car suddenly dies while driving, then that is a sign that your fuel pump relay is not functioning as it should.

How to fix a bad fuel pump relay?

Although it is possible to fix a damaged or faulty fuel pump relay, this is usually not a wise move. The best solution is to replace it. Replacing a faulty relay is much cheaper than fixing it.

The only time when fixing the relay is recommended is if the issue is caused by things like dust. However, if this crucial component is badly damaged, then the best solution is to replace it.

The good news is that the fuel pump relay is one of the cheapest components in the combustion system.

While it is not as cheap as the fuse, the fuel pump relay price ranges between $20 and $50. More so, since fuel pump relays are readily available, the cost of labor is also very affordable.

The only instance where the mechanic will charge you more money is if it takes him more time to troubleshoot the problem. The entire process of replacing a faulty fuel pump relay will not take more than 15 minutes to complete.

Can a bad fuel pump relay cause the car not to start?

Yes, a bad fuel pump relay can make your vehicle not start. The fuel pump relay plays a crucial role in ensuring that the car has sufficient power to pump fuel to the engine.

So, if it is faulty, then your car may not start because the engine does not get sufficient fuel. One of the major signs of a faulty fuel pump relay is if the car does not start.

How do you start a car with a bad fuel pump relay?

There are many ways of starting a car with a bad fuel pump relay. Below are the most recommended techniques.

1. Use a fuel pressure gauge

When the fuel pump relay is faulty, the pressure will be low, meaning your car will not have sufficient pressure to supply fuel to the engine for it to start.

The best solution to this is using a fuel pressure gauge. It will provide the much-needed pressure, thus allowing the fuel to get to the engine.

2. Allow the engine to cool

A drastic increase in engine heat is a sign of a faulty fuel pump pressure. A solution to this is to allow the engine to cool before restarting it.

When the engine cools off, the fuel pump relay will reset without the need for pressure. The engine should not be too hot or cold, it should be somewhere in between.

Do fuel pump relays often fail?

No fuel pump relays don’t fail often. They are among the most durable components of a car. A brand-new relay can last for between 8 and 15 years. However, your driving style and the car brand will also determine how long the fuel pump relay will last.

Can a bad fuel pump relay drain the battery?

YES, a bad fuel pump relay could drain the battery. This mostly occurs when the relay shorts. The Relay can drain the car’s battery even when it is turned off and over time, the battery will eventually drain the battery completely. So, if your car battery keeps draining, then the problem could be a faulty relay.

Will a bad fuel pump relay throw a code?

YES, a bad fuel pump relay can throw a code. The error codes that the bad fuel pump relays are likely to throw include P0201, P0231, P0267, P0232, P0268, P0030, and P0087. The trouble code displayed depends on your car’s make and model.


The fuel pump relay is one of the most crucial parts of the car. If it fails to work, then your car will not start or will stall. Fortunately, this device can work intermittently but only for a while.

If you don’t replace it quickly, it will get damaged permanently, thus stalling your car. Therefore, it is important to ensure that you replace the relay the moment you discover it is faulty.

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