Virtually all car’s electrical components rely on a fuse to operate. That’s why modern cars have over 40 fuses that protect the electronic system against short-circuiting and overcurrent.
One of the most critical fuses in your vehicle is the EFI fuse. But what is an EFI fuse, and what does it do?
Herein I discuss the EFI fuse to help you understand its role in your car’s electronic system. You’ll also discover the most common EFI fuse issues, how to address them, and more.
Answer: EFI Fuse Meaning
An EFI (electronic fuel injection) is integral to your car’s EFI system. It sits between the power source and the fuel injectors.
But what does the EFI fuse control in the system? Like other fuses, the EFI fuse acts as a buffer between the power source and the components it protects. It controls the electric current flowing through the EFI system. In other words, this fuse prevents voltage surges that might cause damage to the circuits and the injectors.
Without the EFI fuse, the electricity from the power source will overwhelm the fuel injectors and the circuits. A functional EFI fuse allows the fuel injectors to deliver the correct amount of fuel to the combustion chamber. If the fuse is defective, your car might fail to start or stall while driving.
To understand how this fuse functions, it’s essential to detail the role of the EFI system. This system comprises the EFI fuse, fuel injectors, a fuel pump, a fuel rail, and a fuel pressure regulator. It’s found in modern cars to replace carburetors.
Unlike carburetors, the EFI system is more efficient regarding fuel supply to the cylinders. Vehicles with the EFI system are more fuel efficient, have lower exhaust emissions, and have better engine performance.
Each cylinder in the EFI system receives fuel from its fuel injector. The fuel mixes with air in the intake manifold before entering the combustion chamber. This system works with the vehicle’s ECM to control the fuel injection. The goal is to ensure efficient fuel delivery into the combustion chamber.
The electronic fuel injectors require power to inject fuel into the cylinders. And as an electric component, the fuel injectors can succumb to damage in case of voltage surges. Luckily, this is where the EFI fuse comes in.
The fuse reduces the electric current from the power source to ensure the injectors receive the correct current. As a result, the injectors work smoothly to direct the right amount of fuel needed in the combustion chamber.
Answer: EFI Fuse Issues
In normal circumstances, your EFI fuse Toyota should last decades. However, various issues with the electronic components and wiring can cause premature damage to the fuse. Below are the EFI fuse problems and how to fix them:
Blown EFI Fuse
An EFI fuse blowing is a common issue Toyota owners encounter. The fuse blows out due to overcurrent or short circuits in the EFI system. In the case of an overcurrent, the fuse will blow to prevent excessive current from reaching the fuel injectors.
The injector wires could also be to blame if the fuse keeps blowing. Damage to the wires, particularly the wires supplying power to the O2 sensor and the injectors, can short and cause the fuse to blow.
When the EFI fuse blows out, its thin metal strip tends to break apart, preventing current flow to the injectors. Sometimes, the fuse’s metal strip might also melt or appear burnt. In this case, the fuse will emit a burnt smell from the fuse box.
Replacing a blown EFI fuse can resolve the problem. Start by locating and inspecting the fuse. If the fuse looks burnt or the metal strip appears broken, you’ll need to replace it. Use a fuse puller or needle nose pliers to remove the fuse from the panel.
When pulling out the fuse, avoid bending it side to side. Doing this can result in damage to the fuse box terminals. After pulling the blown fuse out, replace it and ensure the new fuse has the correct amperage.
Some car owners wonder why the EFI fuse keeps blowing after replacement. In most cases, the EFI fuse will frequently blow out due to the following:
- Installing a fuse with low amperage
- Frayed wires that cause electrical shorts
- Faulty alternator
So when installing a new EFI fuse, always check the car owner’s manual to know the recommended amperage for the fuse.
If the fuse blows again, inspect the wiring harness in the EFI system. Broken or frayed injector wires can create electrical shorts and blow the fuse. To fix this problem, call an expert to examine and replace the defective wiring.
A faulty alternator might overcharge the battery. An overcharged battery delivers excess current through the EFI system, causing the fuse to blow out. It’s best to allow a professional to examine the alternator and the battery to determine the cause of the problem. Your professional might repair or replace the defective alternator.
Defective EFI Relay
The EFI relay serves as a secondary switch for electronic fuel injection. This switch is between the power source and the EFI. Over time, the EFI relay can wear out and cause the fuel injectors to malfunction.
Sometimes, issues with the EFI relay can cause the fuse to blow continually. So if you install a new EFI fuse without replacing a defective relay, the fuse might blow out again. To avoid this issue, test the relay using a multimeter. If the Ohms reading is outside the recommended range, replace the relay.
Location of the EFI Fuse
When replacing a blown EFI fuse, you’ll need to know where to locate it in your car. Like other car fuses, your EFI fuse Toyota is in the fuse box.
Many modern cars feature two fuse boxes for holding the fuses. You’ll find one in the engine bay and the other in the cabin. Most cars have the EFI fuse in the fuse box located in the engine bay. You can, however, consult the manual to find the fuse box holding the EFI fuse.
After locating the fuse box, open it and look for a fuse marked as EFI. Some cars have this fuse marked “INJ” to indicate injectors. Other vehicles have diagrams and numbers on the fuse box cover for all the fuses.
Answer: How to Test the EFI Fuse
If you suspect your vehicle has a faulty EFI fuse, ask a friend to turn the engine on. As the car turns on, you should hear the fuel pump working.
Listen for the sound as the injectors inject fuel into the combustion chamber. The EFI fuse might be faulty if you don’t hear any sound from the fuel pump.
Next, open the fuse box and press the relay button next to the EFI fuse. Let your friend turn the engine on and listen for a “click” sound. If the EFI fuse is functional, the relay button should click. The EFI fuse is faulty if the button won’t click.
Wrapping Up
The EFI fuse is essential to your vehicle’s electronic fuel injection system. It controls electricity flowing to the fuel injectors. This fuse protects the EFI against electric shorts and overcurrent.
If your car has a blown EFI fuse, the fuel injectors won’t inject fuel into the combustion chamber. As a result, your vehicle might fail to start or stall while driving.
The best way to solve this issue is by testing and replacing a blown EFI fuse. If you can’t fix issues with the fuse, hire an expert to inspect the EFI system and resolve the problem.