Fuel Injectors

Maintaining Precision – Fuel Injectors

Over the past three decades, as fuel injectors moved from the intake manifold to the combustion chamber, they have become more precise in dispensing fuel. To maintain this precision, vehicle owners should be on their guard for signs that their vehicles' fuel injectors require service or replacement.


  • For instance, it only takes an eight to ten percent restriction in a single fuel injector to cause a "misfire" (incomplete combustion in the engine cylinder that shakes the vehicle enough that the driver can feel the vibrations).
  • This occurs as unburned oxygen enters the exhaust and makes the O2 sensor read lean.
  • Newer direct fuel injectors are more sensitive to restrictions because they inject precise amounts of fuel into the combustion chamber.

Residual debris in the fuel system or dirty fuel can caused blocked injectors. A common problem. when individual fuel injectors are blocked, it can reduce their ability to deliver the fuel-air mixture to the engine properly and cause rough performance.

TIP: Dirty fuel injectors in turbocharged engines can make the fuel/air mixture dangerously lean, resulting in engine-damaging "detonation" (also known as "knocking," premature spontaneous burning of a fuel-air mixture).

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Written by Developer Autoshop