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Engine

What are Fuel Injectors?

Spray a fine mist of fuel into the engine.

ECUHigh-pressure fuel railPSI#1#2#3#4ECU pulses injectors in order 1-3-4-2 — fine mist meets air, ignites, drives piston down

Simplified animation — not to scale.

In plain English

Precision-engineered nozzles that open and close thousands of times a minute to spray atomised fuel into each cylinder (or the intake) at exactly the right instant.

A simple analogy

"They are like the engine's perfume atomisers — a tiny, perfectly timed spritz of fuel for every bang."

How it works

The ECU tells each injector when and how long to open. The finer the mist and the better the timing, the cleaner and more efficient the burn.

Signs of trouble

  • ⚠Misfires or rough running
  • ⚠Smell of fuel
  • ⚠Increased fuel consumption
  • ⚠Black smoke from the exhaust
Rough UK cost

£200–£1,200 depending on number replaced

Parts: £60–£300 per injector
Labour: £100–£400

Always get a written quote. Prices vary by car, region, and parts brand.

Heads up: Carautonomy is for general guidance only. If your car is showing warning lights or behaving oddly, get it looked at by a qualified mechanic.

Keep exploring

Alternator
The on-board power station that keeps your battery topped up.
EGR Valve
A small valve that recycles exhaust gas to reduce emissions.
Starter Motor
The muscle that turns your engine over when you twist the key.

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A friendly note

Information here is general guidance, not a diagnosis. Always speak to a qualified mechanic before parting with cash.

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