Simple technique of testing fuel injector

To save your time and money bringing your vehicle to the mechanic only to find out there’s nothing wrong with it, Automilas put here simple steps testing the fuel injector on your own. Read on!

The job of a fuel injector is quite simple: to supply fuel to the engine. Fuel injector is a new technology found in most modern vehicles. Though effective, it can also malfunction and give you migraine. That is why knowing how to troubleshoot your car fuel injection system is quite important. This, you will do without breaking much of a sweat. Before we dive into these simple techniques, there is need for you to know the simple mechanics of a typical fuel injector.

1. Fuel injector in mechanic term

The fuel injector is an electronically aided mechanical device in charge of injecting the precise quantity of fuel into the engine. It plays a very vital role in ensuring complete mixture of air and fuel, resulting to a complete combustion. This simple process is applicable to both diesel and gasoline engine. When your fuel injector is faulty, you will notice the following symptoms such as oil thinning, problems starting the vehicle, pollution, smoke emission, increased fuel consumption, failed engine, failed emission and strong fuel odour among other issues.

2. Testing fuel injector at home

These techniques will be sub-divided into units such as fuel injector and how to listen to the sound of an injector. The most important tip is adhering strictly to safety precaution by putting your car engine off.

2.1. How do you listen to the sound of fuel injector?

This is quite simple; the steps below will guide you along the way:

  • Wear safety gloves
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You must always wear your safety glove to protect yourself during this process. Right in your safety gear, you will find safety tools such as your hand glove. The role of the hand glove is to eliminate any possible case of cut or injury inflicted by sharp objects. Safety glasses must be handy as it provides protection for your eyes. This goggle is specifically designed to shield your eyes to harmful exposure to debris or spraying job. The vital information in this step is that, you must always buy safety tools that are fitted into your size to hasten your job and productivity.


Remember: safety comes first before fixing anything!

  • Locate the fuel injector

At this stage, you have to find the location of the fuel injector. The golden question is, how do you do that? You probably may need to revisit your car manual to check the location of each injector in every cylinder and how they are linked to the fuel rail. Right on the manual, locate the maintenance section to know where to look.

  • Take a long & thin screw

This is when you need your long and thin screw driver to test your fuel injector. Make sure that your screw driver comes with safety features such as plastic or rubber handle for your protection.

  • Keep quiet & listen

To listen to the sound of the fuel injector, you need to put the tip of the metal rod on the injector the moment the engine starts running. When you are unable to hear any noise, it means there is an activation problem with your injector or some other similar problems

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2.2. What is the technique for testing fuel injector?

These simple troubleshooting steps should be able to put you out of mechanical misery. The basic idea behind fuel injector is to inject fuel into the combustion chambers in form of vapors. Yet, it is really complex fixing an injector problem. The good news is, you can fix this problem with the use of your hand. The following steps are to fix your fuel injector right away:


The state of your car fuel injector system affects the performance of your engine

  • Activate the ignition key but don’t start the engine

The first step is to enable the electrical system by activating the ignition key without starting the engine. At this point, you will need your car battery to be at optimal level by turning off all electrical devices in your vehicle.

  • Connect the tester to battery terminals

This is when you connect the tester to the battery terminals. To do this, you have to connect the electric plug and the small clamp, which is at the end of the wire that comes from the power cord, to the closed circuit. Once you do this, the indicator light located on the handle will come up. To locate the cathode, you should insert the end of the wire into the negative battery.

One common feature of an injector is the presence of plastic connector with two wires coming out (black and grey). One of the wire should contain a voltage of 12volt, which is directly enhanced by your car electrical system.

  • Use the test pen
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Penetrate the rubber layer by using the top of the test pen. This allows the test pen to touch the metal wire inside. The light that comes up will allow you to mark the power cord and mass connector. This is also essential for the back stepping steps. The reason behind this is to check the voltage of each wire.

Video: Using basic tools to test your fuel injector (source: scannerdanner)

  • Repeat all again

All the steps listed should be repeated again to test other injectors in separate cylinder. This will save you time in case the service of a technician is required to repair the faulty injector. The technician will not waste time by checking the fuel injectors again.