Fuel Injectors Information

Fuel injectors are electromechanical valves that dispense a fuel mist into an engine and can be controlled to deliver precise amounts of fuel at specified time intervals.  Fuel injectors are part of the fuel injection system used in internal combustion engines that deliver fuel to the cylinders of the engine. 




Selecting fuel injectors





The primary function of a fuel injector is to provide fuel to an internal combustion engine.  The fuel is pressurized and passed through a filter and flows into the body.  The needle prevents the fuel from passing through the body which is held down by a spring.  Once the chamber is full the solenoid coil is energized and moves the plunger back, opening up the tip of the injector allowing fuel to be sprayed.  The needle is then closed after the solenoid is no longer energized and the spring pushes the needle tip back.  The entire process takes milliseconds and varies depending on engine performance.Fuel Injectors


Types of Fuel Injectors


  • Top-feed - Fuel enters from the in the top and exits the bottom.
  • Side-feed - Fuel enters on the side on the injector fitting inside the fuel rail.
  • Throttle body injectors - (TBI) Located directly in the throttle body.


Types of Fuel Injection Systems


  • Throttle body injectors or single point injectors (TBI)
  • Port or multi-point fuel injection (MPFI)
  • Sequential fuel injection (SFI)
  • Direct injection




  • Automotive
  • Marine
  • Motorcycle




BS ISO 12251 - Mounting dimensions for clamp mounted CR fuel injectors


BS ISO 14681 - Calibrating fuel injectors




Pro Flow Tech—Types of Fuel Injectors


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Engine Basics




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