How To Test Your Fuel Injectors At Home

Checking my fuel injectors using several methods without a mechanic expert

The fuel injectors on the engine of your vehicle need to be well maintained for you to enjoy optimal performance from the engine of the vehicle that you are driving.

The fuel injectors work to allow appropriate proportions of fuel to the engine; not too much or too less.

This would serve to make your engine run smoothly and avoid any hitches when you are on the road driving your vehicle.

Here’s how you can test your fuel injectors through the following means:

1. Testing The TBI Injectors
2. Testing The EFI Injectors

Therefore, you can always test the condition of your fuel injectors by your own without the need of an expert.

All that is needed is a series of steps and you would be able to determine whether you would have to replace the fuel injector or not.

1. Testing The TBI injectors

The TBI injectors offer you a simple way to visually test the working of the fuel injectors simply. You can inspect complications within the fuel injectors that will be seen in the way the fuel will be spread.

You can test for the fuel spray in this way:

  • Remove the cover from the housing of the air cleaning.
  • Let someone start the engine and have them crank it up if it does not start as needed.
  • Evaluate the pattern of the spray that comes from the injector.

If the fuel is coming out in a partially atomized and in an inverted V pattern, then the fuel injector would be in good condition.

However, if you notice a solid and a spray pattern that appears to be in a single like pattern, which is also an irregular pattern- then the injector is faulty because of dirt deposits.

It may also be affected by the internal components not working as they need to.

For more details, watch this video:

2. Testing The EFI injectors

Electronic Fuel Injector (EFI) does not access the components of the spraying of the fuel for inspection purposes. Its structure is not simple and will need an expert to understand it’s working.

You will have to get some equipment for the inspection work of the spraying pattern that is seen from each of the fuel injectors.

For this test, you will have to inspect each of the fuel injectors and check if they are in excellent working condition or not.

The process for inspecting the fuel injectors is done using the following series of steps:

  • For the first step, you will need to use a piece of thin hose pipe of an appropriate length or mechanic’s stethoscope or a long standard screwdriver to listen to the injector.
  • Ignite the engine of the vehicle and leave it in idling for sometime.
  • Step on the parking brake and lift open the hood of the vehicle.
  • Take the earpiece and place it on either of your ears to listen to the sounds inside the injectors.
  • If the injector works well, you will hear a clicking sound inside. The sound is produced by a solenoid that is inside the injector deactivating and activating the injector’s valve. If there isn’t a click sound, either the computer is not sending the pulse signal or the solenoid has broken. It means you have a dead injector.
  • Go through the whole process once again on another injector and make a note of dead injectors, then you can test them in the below section.

This video also helps you:

Ways To Check Your Dead fuel Injectors

You could always check the coil of the injector to test if it is dead or not. For this test, you will have to use a resistance value for the coil that is in the injector as well as a multimeter you can use.

The value of the resistance can be figured out by checking one the owner’s manual of the vehicle.

After knowing the resistance value, you can then set it on the multimeter and then switch off the vehicle.

Polarity does not matter in this case, so it will be simple for you to conduct this test on your own without the help of an expert.

If the reading is at zero, then the coil is shorted and it is partially opened if the reading appears to be jumping all over the meter.

To get to know this about this topic better, then watch this video:

How To Take Care Of Your Fuel Injectors

Prevention measures would work to provide you with a solution against the complications that are brought about by fuel injectors that are not in the best condition.

Just like any component of the vehicle, prevention damage works to cushion against any costly expenses when correcting some of the damages on our vehicles.

An effective preventive measure is regular cleaning of the fuel injectors. You can do this using a cleaning fluid that will work to prevent them from clogging up. Dirt would also be done away with.

Regular checking on the fuel injectors and all other associated components would help avoid any of the damages caused.

You can check for fuel deposits and leakages that might show the beginning of a fault in fuel injectors.

You would also be forced to replace severely damaged fuel injectors to avoid any of the subsequent damages faulty ones will cause.

You could always get a set of new fuel injectors that would guarantee optimum performance whenever you have them installed.

How To Test Diesel Fuel Injectors

For your diesel fuel injectors to work as they are needed to and in top performance, they need to be well maintained.

The maintenance activities are simple steps that you can accomplish on your own at home without the need for an expert intervening to assist.

You can test them to determine their current condition and decide whether replacing them would be the best action to take.

You will be able to replace the injectors by your own as it is also a simple task, especially when you have the tools required and adhere to the instructions provided.

You can test the performance of your diesel fuel injectors by following these steps:

Step 1: Assemble The Necessary Tools For The Task

The first tool that you will need to have is safety gear because you will be exposed to specific items that might harm you.

Gloves for your hands and goggles for your eyes will protect them from spills that may cause you to experience some irritation on your skin.

A metal rod that is a foot long and a screwdriver will also be important for the task as well as an automotive test light.

Step 2: Make Use Of Your Sense

For the testing of the diesel fuel injectors used for your vehicle’s engine, you will have to be keen on your senses.

The first step would be to start the engine and then take the metal rod and position it over the fuel injector.

You should then lean your head and it should get as close as it can to the rod and be alert for any vibrations.

You should not be too near to the engine as it gets too hot and can burn your skin. A clicking sound would be heard if the fuel injectors are activating.

Step 3: Turn On The Battery

The next step is checking the electrical connection of the vehicle’s systems. You can do this by switching off the engine and let it not run for a while; this is as the battery isn’t activated.

The electronic accessories like the stereo, lighting and the ac systems should all be working, just not the engine.

Step 4: Get The Test Light

The automotive test light will be used to check the electronic connection of the vehicle.

You can do this by connecting its clip to the negative terminal of the battery and get the pointed tip to touch a part of the wire that is exposed.

It should light up when you touch the wire, you can repeat this for all the other fuel injectors.

Step 5: Make Your Decision

You will be able to determine the functioning of the diesel fuel injectors through the above steps.

If they are in a bad condition, you can either opt to repair them or replace them from the engine of the vehicle.

You should be able to replace the diesel fuel injectors by yourself thanks to the comprehensive instructions for getting the job done.

You could also get a mechanic or an expert do that for you if you can’t manage yourself.

The major cause that might make the diesel fuel injectors in your engine unable to function effectively are deposits of carbon on them.

Others are the external and internal deposits from the fuel injectors themselves.

For more details, you can watch this video:

How Do You Know If Your Fuel Injectors Are Clogged?

The fuel injectors in your vehicle might get clogged especially if the fuel filters are letting it deposits that end up to clog the injectors.

You should be able to know this through the following abnormalities in the working of the vehicle:

Engine Issues

The engine might be affected in that it would not be able to start as smoothly as it did previously.

This might be caused by the fuel injectors incapacity of letting through enough fuel to the engine compartments that are needed for the starting of the engine.

If less fuel is let through, the engine might not even start. If you are also keen and notice sputtering and signs of misfiring, then the issue might just be the clogged fuel injectors.

Complications When Accelerating The Vehicle

The fuel injectors are clogged and they let in insufficient proportions of fuel to the engine compartment of the vehicle.

Enough fuel is needed for the smooth acceleration of the vehicle and this might make it difficult for the vehicle to accelerate as it formerly did when the fuel injectors were in excellent condition.

Rough Idling

For the smooth idling of your vehicle, the fuel injectors should be able to let in enough fuel through to the engine in a consistent manner.

If this is not possible because of the clogging of the fuel injectors, you would notice that the engine idles in a rather violent or rough manner.

A violent or rough is one sure way that you can use to test the fuel injectors on your vehicle.

Increased Fuel Consumption

When the fuel injectors of your vehicle engine are clogged, fuel will be lost through leakages on the various components of the vehicle.

They might also be damaged in that they would be injecting too much fuel to the engine of the vehicle.

This will make you have to top your fuel tank severally at a particular time interval; which is significantly different than you did before.

You could also notice this if the fuel injectors are leaking and losing fuel to the external environment; in which more fuel would be lost through the system.


The fuel injectors located in the engine of your vehicle play a vital role in determining the performance of the vehicle.

If they are either clogged or damaged, you would have a difficult time driving the vehicle because of the inability of the engine performing at its optimum capacity.

That is why you would have to test the fuel injectors occasionally to test whether they are in proper working condition or not.


1. AxleAddict –


Written by Kane Dan

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