Simply put, the fuel injector in your engine is in charge of putting fuel into the combustion chamber. Each cylinder has its own fuel injector. The fuel moves from the tank through the fuel lines and into the injector before it gets dispersed.
These days most diesel cars and quite a few petrol vehicles use a direct injector, which delivers the fuel in precise bursts as it is pushed through a nozzle under high pressure.
In cars with an indirect fuel injection system, the fuel goes through an injector into the inlet manifold or a so-called pre-combustion chamber, where it is mixed with air and ignited. That in turn forces the fuel into the combustion chamber.
Direct fuel injection brings the fuel, as the name implies, directly into the chamber. This happens under high pressure and once the fuel meets the incoming air stream in the cylinder, self-ignited combustion occurs, moving the pistons.
Most fuel injectors are controlled electronically these days with an ECU (Electronic Control Unit) corresponding with the injector's solenoid plunger. The unit monitors and balances speed, torque, air temperature, etc., making sure that the administration of the fuel-air mixture is perfectly timed. This makes the car more powerful, fuel consumption more economical, and most importantly it reduces emissions. Altogether, electronic fuel injection systems are more efficient and more reliable.
Injectors have a tough job considering that they constantly deliver high-pressured fuel through tiny nozzles. Needless to say, this can cause fuel injector problems over time.
There are a few reasons why the fuel injector can fail. These are the most common ones:
Solenoid failure - The solenoid can wear out over time or malfunction. This causes problems because the nozzle won’t know when to open and thus fuel cannot be injected.
Spring malfunction - The return spring in the injector can malfunction if there is damage to other engine components. Especially at higher RPM, this can cause the fuel system to misfire.
Clogged nozzle - By far the most common cause of a failing fuel injector is a clogged nozzle. This usually happens over time due to the use of low-quality fuel or a dirty fuel filter. To prevent this from happening you should only buy high-quality fuel and change the filter regularly.
Fuel injector costs vary depending on the car make and model. In many cases, you can use a cleaner yourself to clear the fuel injector of dirt. However, in more severe cases a mechanic will have to do the fuel injector cleaning.
In some injectors, faulty parts like the solenoid can be replaced or cleaned individually. If the injector has cracked or is heavily corroded though, it is time for a fuel injector replacement. On autobutler.co.uk you can request quotes from garages near you to compare prices for fuel injector replacement or cleaning.
There are a few signs you might notice that indicate a defective or clogged fuel injector:
Leaking fuel injector - This can be detected through a fuel leak in the engine bay. If you open the hood of your car and you can either see or smell fuel, it might be an indication of a cracked and leaking fuel injector.
Higher fuel consumption - If you are following all the rules for economic fuel consumption and you still notice that you have to fill your tank more often than usual; it could be due to a faulty fuel injector.
Since the fuel injector is in charge of bringing just the right amount of fuel into the chamber, higher fuel consumption could be an indication the injector is over-delivering.
Driving is uncomfortable - Chances are that a clogged nozzle will lead to misfiring, as the chamber is getting too little fuel to ignite combustion, or none at all. This can also lead to issues when starting the car. However, it is also possible that too much fuel is administered at once when the injector is defective. This can cause the car to surge too fast.
Either way, it will make driving more uncomfortable.
Rough idle - When the fuel-air mixture is not balanced due to a faulty fuel injector, it can lead to an uneven idle state. This is probably the easiest tell-tale of a problem with the injector.
Smoke - Another concerning side effect of a faulty fuel injector are increased emissions. You can notice this if you see smoke coming from the tailpipe, which is caused by unburnt fuel from an overactive injector.
Whenever you notice any of these issues with your car, it is time to take it to a garage to have a mechanic check if the fuel injector needs cleaning or replacing.
| Make | Compare and save* | You save on average* | Ratings | |
|---|---|---|---|---|
| Audi | £140 | 25% |
5.0
(4)
4
0
0
0
0
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| BMW | £102 | 27% |
3.5
(2)
1
0
0
1
0
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| Citroën | £161 | 23% |
5.0
(1)
1
0
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0
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|
| Ford | £141 | 24% |
4.7
(9)
7
1
1
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0
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| Mercedes-Benz | £172 | 21% |
4.7
(3)
2
1
0
0
0
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| Nissan | £223 | 25% |
4.6
(5)
4
0
1
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| Peugeot | £153 | 24% |
4.5
(8)
7
0
0
0
1
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| Seat | £180 | 26% |
(0)
|
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| Vauxhall | £197 | 29% |
5.0
(13)
13
0
0
0
0
Read the reviews
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| Volkswagen | £134 | 30% |
5.0
(6)
6
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Read the reviews
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|
| Make | Save on average* | |||
|
Audi
5.0
(4)
4
0
0
0
0
Read the reviews
|
£140 / 25% | |||
|
BMW
3.5
(2)
1
0
0
1
0
Read the reviews
|
£102 / 27% | |||
|
Citroën
5.0
(1)
1
0
0
0
0
Read the reviews
|
£161 / 23% | |||
|
Ford
4.7
(9)
7
1
1
0
0
Read the reviews
|
£141 / 24% | |||
|
Mercedes-Benz
4.7
(3)
2
1
0
0
0
Read the reviews
|
£172 / 21% | |||
|
Nissan
4.6
(5)
4
0
1
0
0
Read the reviews
|
£223 / 25% | |||
|
Peugeot
4.5
(8)
7
0
0
0
1
Read the reviews
|
£153 / 24% | |||
|
Seat
(0)
|
£180 / 26% | |||
|
Vauxhall
5.0
(13)
13
0
0
0
0
Read the reviews
|
£197 / 29% | |||
|
Volkswagen
5.0
(6)
6
0
0
0
0
Read the reviews
|
£134 / 30% |
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