What do the fuel injectors do?

Fuel injector replacement Hamilton

Fuel injectors are found in all diesel vehicles and most modern petrol vehicles. Each engine cylinder has one injector assigned to it, meaning the number of fuel injectors in your vehicle varies depending on your engine configuration.

In a combustion engine, fuel injectors are often used to introduce fuel to the engine’s intake manifold and internal combustion chamber. Petrol or diesel is delivered from your fuel tank to the injectors using a fuel pump. The fuel injectors introduce a certain amount of fuel, depending on the air levels in your engine (calculated from the engine Mass Air flow (MAF) meter). This allows the fuel to mix with the right amount of air and burn, giving the engine the necessary power to operate the vehicle and produce the minimum amount of engine exhaust greenhouse gases.


What are the causes and symptoms of faulty/failing fuel injectors?

Clogged/dirty injector

Over time, fuel injectors can become clogged due to hydrocarbons, sediment and other contaminants in your car’s fuel. Symptoms of a clogged fuel injector include:

  • Cylinders not firing properly (misfiring)
  • Erratic engine idle
  • Black smoke from engine exhaust pipe (leaking injectors, too much un-burnt fuel in engine and exhaust)
  • intermittent acceleration problems
  • Reduced vehicle power
  • Fuel too lean (too much air and not enough fuel)
  • Check Engine Light (CEL) on the dash
  • Catalytic Convertor light on (due to excess fuel in exhaust system from leaking injectors, which overheats catalytic convertor)

There are several fuel injector cleaners available. However, these can soemtines make the problem worse. As the cleaner removes contaminants from the fuel system, pumping them towards the fuel injector and causing an even bigger build-up.

At our workshop, can remove your fuel injectors and get them ultrasonic cleaned to remove contaminants from the fuel injector. After they are cleaned, the injector(s) are tested to ensure that the flow (volume of fuel over time) and spray pattern are correct. See how some companies flow test injector here, flow testing injectors


Leaking fuel injector

Externally leaking fuel injectors – will result in limited or no fuel delivery to the engine. The fuel pump will also have to work harder to deliver more fuel to the engine. Externally leaking fuel injectors will need to be replaced immediately as they pose a direct fire risk.


Internally leaking fuel injectors – mean that the fuel injector needle (or pintle) does not seal properly allowing fuel to leak into to the intake manifold or combustion chamber directly. This will make the air / fuel ratio to rich, and often you will get Long Term Fuel Trim related fault codes, high exhaust emissions of greenhouse gases, rough engine running, black smoke from the exhaust and other poor engine performance symptoms.

Some symptoms of a leaking fuel injector include:

  • Increased fuel consumption
  • Strong fuel smells and leaks from under your engine
  • Reduced engine power
  • Black smoke out the exhaust tail pipe
  • Strong smell of petrol
  • Catalytic Converter light on, and an unusual exhaust smell
  • Check Engine Light on


Unresponsive fuel injector

Your vehicle’s computer controls how much fuel enters the engine. An unresponsive fuel injector will not respond to signals from your car’s onboard computer. This will result in the injector needing to be replaced, or the fuel injector wiring fixed, or the car computer fuel injector driver circuit being fixed or the computer being replaced. Symptoms of an unresponsive fuel injector include:

  • Engine light on
  • Cylinder not firing
  • Reduced engine power
  • Engine runs rough at idle and shakes
  • Engine sounds different


Other fuel system problems

The fuel injectors aren’t always the culprit to your fuel problem. Other common problems include:


Fuel Injector Replacement in Hamilton

At Grimmer motors, we can replace your vehicle’s fuel injectors. This will allow for improved fuel economy, decreased exhaust emissions. increased engine power and smoothness of engine running. Our expert mechanics can quickly diagnose problems in your vehicle’s fuel system, allowing you to save time and money.

For fast, efficient fuel injector replacement and servicing in Hamilton, contact Grimmer Motors today!

Please Note – we don’t generally stock or supply just “parts only” for this service. We are a general automotive repair workshop. If you are able to bring your vehicle to us, we can diagnose the problem, find and fit the necessary parts, or organise the appropriate service for you.


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