Fuel Injectors – Will usually only fail, in one of, three different ways.

Fuel Injectors - Will usually only fail, in one of, three different ways.
Fuel Injectors - Will usually only fail, in one of, three different ways.

So, fuel injectors are now used in pretty much all passenger vehicles.

Fuel injectors are a vital part of a complex, fuel management system.

Furthermore, new technology has made fuel injectors more precise than ever, in dispensing fuel.

If the fuel injectors are not operating properly, then other parts of the engine will be affected as well. Therefore, if this precision is thrown off by restrictions; electrical problems or fuel problems, it can cause driveability issues.

Consequently, vehicles regulate your speed and acceleration, by varying the ratio, of the fuel and air, entering the engine.

Fuel Injectors
Fuel Injectors

In order to provide the right amount of fuel; the engine control unit is equipped with, a whole lot of sensors.

Fuel injectors deliver fuel to the combustion chamber, directly or indirectly. During its evolution the fuel injector has moved, from the intake manifold, to the combustion chamber.

Common Types Of Injectors Include:

  • Throttle Body Injection
  • Multiport Injection
  • Sequential Injection
  • Direct Injection

A Fuel Injector Will Usually Only Fail, In One Of Three Ways:

From Being Dirty Or Clogged

Over time the nozzle of the injector can become, dirty and partially blocked. When you shut off your engine the injector will, soak up the heat of the engine.

Dirty Or Clogged Fuel Injectors
Dirty Or Clogged Fuel Injectors

This causes any fuel left in the injector to evaporate, leaving behind hard deposits, inside the injector. Over time, these will eventually, block the injector.

Leaking Externally Or Internally

So, the most common cause of leaky injectors is; the failure of the O-ring, where the injector meets the fuel rail. The O-ring can become, hard and brittle, from the heat of the engine.

Damaged O-Ring Causing Injector Leak
Damaged O-Ring Causing Injector Leak

If it breaks, then fuel can leak out, over the engine. The other way an injector will leak is, if the injector body or nozzle cracks.

From A Mechanical Failure

There are many moving parts inside an injector and over time they can fail. As a result, of normal wear and tear or lack of maintenance.

Possible Signs Of Fuel Injector Issues, Include:

  • Hard Starting, when engine is hot
  • Poor idle
  • Failed, emissions test
  • Poor Performance
  • Engine does not reach full (RPM)
  • Increased fuel consumption
  • Rough, engine performance
  • Surging and bucking, under various throttle loads
  • Smoke from the tailpipe
  • Oil thinning, which can lead to, catastrophic engine failure
  • Engine Knock or Detonation, which can lead to catastrophic engine failure
  • Pollution

Tracking Down The Problem

Hook Up An (OBD) Code Reader

So, when looking for problems, always start by hooking up an (OBD) code reader. This will tell you if the Engine Control Unit (ECU) has logged any errors. If an engine misfires because of a bad injector; there will be an error code, that will point to, the injector in question.

(OBD) Code Reader
(OBD) Code Reader

If you are using a generic (not vehicle manufacturer specific) code reader; then you can expect to see codes beginning with P02. For example, a fault with an injector in cylinder one, would give a code of P0201. These are all, fuel & air metering injector circuit related codes.

Listen To The Fuel Injectors

Another helpful diagnostic tool, is an engine stethoscope. This tool enables a car owner, to listen for any problems with the fuel injectors; by placing the tip of the stethoscope on each injector.

Engine Stethoscope
Engine Stethoscope

Fuel injectors, make a sharp clicking sound, when they are functioning properly. So, the absence of this sound can indicate, a problem with an injector.

How To Prevent Fuel Injector Problems

In general, fuel injectors are hard wearing and with a little care, can often last; the life of the engine. Like any other engine part, regular maintenance is the key, to keeping them going. If you plan on running up high mileage on your car; then there are a few things you can do to help.

Regular Inspection And Cleaning

So, the most effective way to keep injectors in good working order is; to have them removed and inspected at regular intervals. Under normal circumstances, that would be every 25,000 miles or 40,000 kms. If you tend to do a lot of short journeys; then you’d probably want to have them looked at more often; to prevent the build up of deposits.

Use Of Fuel Additives

Another great way to keep injectors in good health is; to regularly add a fuel injector cleaner, to to your fuel tank. Many manufacturers claim that these cleaners, will give your car extra power or increased mpg.


They probably won’t, or make much difference, to a car that is running properly. I usually do not recommend additives, but this is one area that does help.

Regular Engine Servicing

Regular oil and filter changes will go a long way towards maintaining, a healthy engine. If an engine isn’t running efficiently, this can load extra pressure on injectors. It’s also important, to regularly change the fuel filter, to ensure a proper fuel flow.

Driving Habits

Driving a car hard, combined with short start stop journeys, will increase the wear and tear on injectors. Letting the engine cool down, before shutting it off, will increase the lifespan of the injectors. This will also, benefit the rest of the engine too. As a result, a well kept fuel injection system, will keep your car going for years.

Sometimes A Faulty Fuel Injector, Can Be Repaired:

Leaking Injector

If the O-ring fitted to the injector is the problem; then replacing this O-ring will usually fix the leak. If the injector body; nozzle or internal components are cracked; then a new or refurbished injector is your only option.

Damaged Injector O-Ring
Damaged Injector O-Ring

Replacement fuel injector seals and washers are cheap and are, fairly easy to install. This can often fix the problem, and if you are handy with a wrench, it’s not that difficult to do.

Dirty Injector

It is fairly inexpensive to have your car injectors cleaned and overhauled, by a professional. This involves inspection and cleaning of the injector. That’s why, it is recommended that you should get them cleaned at, regular intervals; to help prevent problems down the road.

Fuel Injector Cleaners
Fuel Injector Cleaners

It can also be a good idea to run a, fuel system cleaner through your engine; a couple of times a year. This will help to keep injectors, fuel pumps and fuel lines clean and clear of, carbon build ups. It will also, increase the service intervals of the injectors.

Clogged Injector

Clogged injectors, can usually be repaired, if you catch the problem quickly. Sometimes a fuel injector is completely clogged, because of years of neglect or a lack of, regular engine servicing. If this is the case then a refurbished replacement, may be the only option. Again, regular use of a fuel system cleaner can help, to prevent clogged injectors.


So, fuel injectors do not last forever. But, you can take steps in preserving their lifespan, for as long as possible. Also, fuel injectors are, a very important component of modern vehicles. Not only do they deliver fuel to a car’s engine, but they do so in a manner that is; efficient as possible.

This not only gives vehicles better gas mileage; but it also cuts down on the pollution that they emit, in comparison to older technologies. When something goes wrong with this sophisticated technology; it can feel intimidating for many car owners; leading them to often take their vehicles for a professional diagnosis.

Thank You !