Test Fuel Injectors in Car

How to Test Fuel Injectors in your Car: Learn The Right Way to Do It

Your vehicle’s fuel system may be in trouble if you find it difficult to press the gas pedal when you are driving. That is only one of the symptoms when the fuel is not correctly distributed to the engine. Hence, a faulty fuel injector might just be the reason why your vehicle has a malfunctioning fuel injection system.

You do not need a professional to test fuel injectors in your car. You just have to prepare all the right equipment to do it on your own. Here are some simple and easy steps on how to test fuel injectors in your car.

  • Prepare Your Vehicle for the Fuel Injectors Testing
  • Use a Multimeter to Test a Deal Fuel Injector
  • Start Your Car and Listen to Your Fuel Injectors
  • Test if the Fuel Injectors Deliver Constant Power

Read on if you want to learn more about how to get the most out of your engine.

What You Will Need to Follow this Tutorial?

Before we begin, you must gather all the materials that you will need to check the fuel injectors in your vehicle’s engine, which includes the following:

  • Quick probe
  • Gloves
  • Test light
  • Protective eyewear
  • Multimeter
  • Mechanic stethoscope
  • Old shop towels

Step-by-Step Guide on How to Test Fuel Injectors in your Car

Test Fuel Injectors

Here’s what you should follow to check the fuel injectors in your vehicle:

1. Prepare Your Vehicle for the Fuel Injectors Testing

Before you start checking your fuel injectors, you must prepare your car by parking it in a safe area and at ground level. You may also wear your gloves and protective eyewear. Keep your shop towels within reach so you can easily use them while you are doing the test.

2. Use a Multimeter to Test a Deal Fuel Injector

Open the hood of your car and find the fuel injector, normally located at the center where the intake manifold is. Turn on the multimeter and set the dialer to ohms, which measures the resistance. Just remember that you have set the dialer to a greater value than what you are expecting.

You may attach the terminal probes of the tester to your fuel injectors to achieve a reading. When you check the values being displayed on your multimeter, the resistance level should be between 11 to 24 ohms. However, you may also check your owner’s manual to see if the reading is within the resistance requirement.

If the reading provided by the multimeter is very high in resistance, it is an indication that your fuel injector is at fault. Do these tests on all fuel injectors and make sure that they are all the same. However, if one has a different reading, it should mean that the fuel injectors are faulty.

One thing to take note of is that you make sure that the fuel injectors are not hot, as high temperatures are likely to affect the readings of the multimeter.

3. Start Your Car and Listen to Your Fuel Injectors

With your mechanic stethoscope, touch the base of the fuel injector and listen to the sound given off by the fuel injector. Make sure that the tip is only touching that area to avoid mixing other noises that come from your car’s engine. You should hear an audible clicking sound from the injector, and if one gives off an unusual sound, it just means that it now needs replacement.

4. Test if the Fuel Injectors Deliver Constant Power

Find the electrical connector of your fuel injector and remove it by pulling up the safety tab while releasing the connector. Once done, you will now be able to see the terminals. Get your test light and turn the ignition key on. If it does not light up, there must be something wrong with the fuse of your fuel injectors.

There is another easy way to test fuel injectors using a probe, a very affordable car diagnostic tool. Here’s what you should follow:

test fuel injectors using a probe
Via: https://www.2carpros.com/articles/how-to-test-a-fuel-injector

1. Start Your Car’s Engine

To turn your quick probe on, just place it on top of a piece of metal. Start your car up and then take the probe while touching the metal end on each fuel injector. Using this tool, you will see that the fuel injector is firing as the light flashes.

2. Listen to Your Fuel Injectors and Look Out for the Flash

Just like the steps provided above, you can also hear an audible clicking sound to see if the fuel injector is firing. You will find complex electronics when looking inside. What they do is that they measure the solenoid that clicks on and off in the fuel injectors.

You will also be able to see it flashing if it is working just right. However, it flashes intermittently when there is a problem with your fuel injector. With this, you can tell if the fuel injectors are working properly if it flashes nicely and as smoothly as possible.

To learn how to test fuel injectors using a probe, you may refer to the below YouTube link:

Pro Tips

  • Using a quick probe will be a lot easier, as you can test your fuel injectors in just a couple of minutes. It is also a very easy way to tell whether you need to replace your fuel injectors or not.
  • The check engine light in your dashboard usually indicates that there is a fuel injector issue. You might want to check it out first before you perform the tests on your engine.
  • If you are not confident enough to test the fuel injectors yourself, you may consult a professional to do these tests for you. If you take your car to the shop, they will be able to diagnose the problem and turn the check engine light off for you.
  • To know if your fuel injector needs replacement, you would want to check if there is a strong smell of gasoline in your car’s cabin.
  • When your fuel injectors are malfunctioning, you will notice that there is hindered acceleration, as well as engine misfiring. This is the best time you check if the fuel injectors are working properly or if they need replacement as soon as possible.
  • It could also be a fuel injector issue if your vehicle starts bucking, stalling, or hiccupping. However, it should be noted that it could also be because of another issue apart from your fuel injectors.


Faulty fuel injectors can be a real pain, as it messes up your car’s engine performance. With this guide, we are confident that you will be able to do it by yourself without needing to pay for professional assistance. All you need is to have all the right tools so you can start testing your fuel injectors to know if they need urgent replacement or not.