Diagnosing Fuel Injector Problems

The creation of fuel injectors was a monumental step toward developing automotive engineering and enhancing the fuel economy of vehicles around the world. The installation of fuel injectors in the engine has turned cars, trucks, and other vehicles into far more efficient machines. Not only has the fuel efficiency gone up, but the amount of pollution caused by the vehicles has gone down significantly as well.

The reason why fuel injectors are so important is because they spray gasoline to the combustion chamber of the car’s engine. Hence, drivers and car owners need to realize the significance of keeping their fuel injectors in a great condition. If fuel injectors sustain damage or become clogged, then the overall performance of the vehicle will be severely affected. Ignoring fuel injector problems can cost car owners huge sums of money in the long run.

Fixing Problems on Your Own

One of the many reasons why car owners are reluctant to deal with fuel injectors is because they are afraid of spending too much money on automobile service shops. A faulty fuel injector does not always require the expertise of a professional mechanic to get fixed. With a little bit of knowledge of car engines and a basic set of technical skills with tools, you could be all that your car needs to run smoothly again. In other words, identifying fuel injector problems on your own can save you the cost of a trip to the service shop.

Common Fuel Injector Problems

If you plan to diagnose fuel injectors on your own, it is very important for you to familiarize yourself with some of the most common problems and symptoms of a faulty fuel injector. The more you learn about these problems, the more accurate your diagnosis will turn out to be. Some of these problems are quite easy to fix. With other problems, however, you will be required to replace the fuel injectors with new ones.

Dirty Fuel Injectors

This is perhaps the most common problem associated with an under-performing fuel injector. Not all of the fuel additives in the fuel get sprayed inside the combustion chamber or the intake manifold. The ones that remain behind end up as deposits or residue on the fuel injector.

The deposits of dried up fuel additives can burn or form a crust when exposed to the intensely high heat inside the fuel injection system. Much of this heat is produced by the friction from rapid and repetitive movement. When a crust forms on the fuel injector, the resultant spray is weak and uneven. This defeats the purpose of injecting high quality fuel injectors.

Clogged Fuel Injectors

A lot of people refer to dirty fuel injectors as clogged fuel injectors, but the two problems are slightly different from one another. When microscopic foreign objects build up inside the fuel injector, it is considered to be clogged. These foreign objects usually settle down in the form of rust. The foreign objects are introduced into the fuel injection system from an upstream source in the gasoline supply.

When your car sits idle without maintenance for a very long period of time, the chances of rust forming in the fuel injection system increases considerably. Once the fuel injector becomes clogged, it will not be able to supply gasoline adequately to the intake manifold.

Closed Fuel Injector

In certain cases, the valve in the fuel injector ceases to function and does not open. This makes it impossible for the fuel injector to spray fuel into the combustion chamber. Faulty windings and rusted fuel injectors are two of the biggest causes of this valve shutting down permanently.

Open Fuel Injector

If a fuel injector remains open all the time, then gasoline will start to leak. This could lead to some really dangerous problems in the vehicle. A faulty spring or a buildup of rust from fuel additives is usually responsible for this defect in the fuel injector.


Gasoline can leak because of other reasons as well. If certain parts of the fuel injection system fail, then there will be a serious leakage for you to deal with. For example, the mechanism that is responsible for keeping the injector cool could fail at any time. When it fails, the gas starts to leak as the fuel injector overheats and stops functioning.

How to Run Diagnostic Tests

Now that you are familiar with the kind of problems that you can expect from a defective fuel injection system, you can learn more about how to conduct diagnostic tests that will help you fix the problem. These tests are quite simple, but they do require you to make use of certain accessories.

1) Measure the Exhaust Manifold Temperatures

When a fuel injector does not close, it heats up. This raises the temperature significantly. On the other hand, a closed fuel injector produces considerably low temperatures at the exhaust manifold. Hence, by measuring the temperature at this particular position, you can figure out whether the valve of your fuel injection system is working properly or not.

2) Listen to the Sound of the Fuel Injector

To do this, you need the aid of an engine or automotive stethoscope. Irregularities in the sound of the fuel injector are a major indicator of the fact that something has gone terribly wrong with the system. The tip of the stethoscope is placed on the top of each individual indicator. If you hear a sharp clicking sound, you can be sure that your fuel injector is in a good condition. The absence of this sound indicates that there is a problem with the injector or the injection system as a whole.

3) Directly Inspect the Fuel Injectors

This is the most straightforward way of finding out whether there is anything wrong with the fuel injectors. The fuel injectors can be removed from the system for close inspection. You need to avoid contact with the fuel. Hence, it is preferable that you put on gloves while handling the fuel injectors. Look for signs of cracks or damage.

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