What is an EFI Fuse? (Explained)

An EFI fuse is the fuse that controls the electricity for the EFI system. The EFI system is how gasoline from the gas tank enters into the cylinders. There, the combustion process turns gasoline into gas fumes. The fumes will ignite and turn into chemical energy. Fuses, fuel injectors, sensors, and a fuel pump are all part of the EFI system.

What is an EFI Fuse?

In order for a vehicle’s engine to generate power, it must convert the gasoline in the gas tank into power. The engine does this by spraying gasoline inside the engine cylinders. There it will mix with air. So the engine needs a device that injects fuel into the cylinders. This device is the EFI or electronic fuel injector. 

Without this injector, the cylinder would fill up only with oxygen and the engine will not be able to perform combustion to generate energy. There would be no power for the vehicle. So now that you know when an EFI is, what is an EFI fuse, and what is its purpose?

First of all, the purpose of any fuse is to redirect some of the power from a power source before it reaches the devices that require its power to function. The fuse is along with the electrical wiring somewhere between the electricity source and the device. The fuse is in the wiring system to act as a buffer between the power source and the electrical device.

If you connect the item directly to the electricity source, the electricity from the engine will overwhelm the device. The device will overload electricity. 

So, an EFI fuse reduces the amount of electricity from the engine before it reaches the electronic fuel injector or the EFI unit.

EFI stands for electronic fuel injector, but the EFI system is not a single inside of the engine. The EFI system consists of the ECU or engine control unit, the EFI sensors, the fuel injectors that spray the gasoline inside the engine cylinders, and the fuel pump.

The EFI system also has a fuse. The EFI fuse is inside the fuse box. A fuse box is where all the fuses in the vehicle are placed for easy access.

EFI Fuse Issues

The fuse is not working anymore – a fuse will always blow out. Whether it takes one year or 5 years, all fuses in your vehicle will need replacing. When you find the fuse box, locate the fuse labeled EFI. Pull out the fuse and inspect it. 

A blown fuse will have some kind of residue on it, like a black mark. It will have lines on the metal part of the fuse that looks like rust, or the plastic on the metal fuse will look melted.

Wiring issues

If you notice the EFI fuse tends to burn out quickly, then the problem is not with the fuse. The problem is actually with the wiring. The wiring could be unstable or it could be a poor conductor, not regulating power from the engine. Check the other fuses in the fuse box. If they are blowing as well, you have a wiring issue on your hands.

How to locate an EFI fuse

Locating the EFI fuse is tricky at first. But once you figure out how to find the fuse, it’ll be a breeze to find it over and over again. 

Here’s how to locate an EFI fuse in any vehicle.

First, locate your vehicle’s manual. If you don’t have your manual anymore, you can download it from the manufacturer’s website. 

Look up the page labeled fuses in the manual. Head to that page. There should be a diagram of the fuse box, as well as the location of the fuse box in your vehicle. Some vehicles have the fuse box above the acceleration and brake pedal. Other vehicles store the fuse box in the engine. Some have the fuse box in the trunk.

The diagram of the fuse box will have a guide with many numbers and boxes on it. Each number corresponds to a fuse located in the fuse box. 

Find the EFI fuse number. 

When you open up the fuse box, the diagram of all the different fuses and their numbers will be on the fuse box cover. Memorize where the EFI fuse is and then open the cover. 

Locate the EFI fuse and then remove it to check its integrity. 

Finding and testing the fuse yourself can save you up to $100 in mechanic labor costs. So you should learn how to remove and test fuses by yourself.

How to test an EFI fuse

If your car has been having some electrical or acceleration issues, you will need to check it out. The cause of these problems could be a faulty EFI fuse. There’s a way to test the EFI fuse in your vehicle and see if it is working properly. If you don’t know where your EFI fuse is, read the section above to find the fuse.

You will need another person to help you with this method. 

Testing to see if the fuel pump is working is simple. As a friend of yours turns the vehicle on, listen for the sound of the fuel injector injecting fuel into the engine. 

If you don’t hear the fuel pump working, then you can test the fuse and the fuel pump relay. Turn off your vehicle. Locate the EFI fuse in the power distribution box. Then press down on the relay button next to the fuse. Now, have your friend turn the vehicle on. When the vehicle is on, you should hear a click from the relay button. If you don’t hear a button click, then the problem is with the EFI fuse.

Conclusion

The EFI fuse is the fuse between the battery inside the vehicle and the fuel pump or fuel injector. There are ways to test the fuel injector fuse. But you must first locate the EFI fuse. It is inside the power distribution box or the fuse box. Fuses are important as they act as a buffer between a power source and a device that requires electricity.