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EFII Systems

Complete EFII Electronic Fuel Injection and Ignition for 4 cylinder and 6 cylinder Lycoming and Continental 520/550 engines.

EFII_kitEFII stands for “electronic fuel injection and ignition”. The EFII system is a complete electronic engine management system for light aircraft engines. We are currently concentrating our efforts on four and six cylinder Lycoming engines and large bore Continental engines (520 and 550). The EFII system can be used in any Experimental category aircraft using one of these engines.

The EFII system is very similar to what you would find on any modern automobile engine. It is a computer controlled electronic fuel injection and electronic ignition system. The system is controlled by an ECU (the computer) and incorporates a fully mapped fuel curve and ignition timing curve. The electronic fuel injection portion of the system utilizes electronic fuel injector valves that are installed into each intake tube, near the engine cylinder. A throttle body replaces the typical carburetor or mechanical injector butterfly assembly. The electronic ignition portion of the system utilizes high energy inductive ignition coils instead of magnetos to deliver a very strong and efficient spark to each plug.

All EFII kits are fully engineered, complete, bolt-on kits that do not require fabrication or special skills. We install weld-in injector bases in the customer’s intake pipes and we install trigger magnets in precision locations in the customer’s flywheel. These services are included in our kit pricing. We provide the remainder of the components to supply you with a complete, easy to install system.

Unleaded Avgas is on the horizon in the near future. If you have an EFII system on your engine, you will already be compatible with the new fuel.

    The advantages of an electronically controlled engine are numerous, and include:

  • Fully compatible with 100LL, auto gas, and future Unleaded Avgas.
  • Up to 10{9187aa996cd9e1f217f9847734a03dc848d9fc3eed7df6d5512c58fdfbd2fd3a} increase in available horsepower.
  • Automatic mixture control (no mixture knob to fool with).
  • A proper ignition timing curve to bring out the true power of your engine.
  • Fuel savings from always having the correct fuel mixture.
  • Decreased lead fouling.
  • Improved engine starting – No “hot start” or “cold start” problems.
  • Decreased weight – no magnetos or mechanical fuel pump.
  • Tunability – your fuel map can be fine tuned to your particular installation.
  • Lower maintenance costs – less lead build up means less wear and less oil contamination, uses long lasting Iridium spark plugs.

The EFII system uses only the highest quality components available. Below is a brief description of each item in the kit.

  • Spark plug wire set, 8 lead (12 lead for 6 cylinder)
  • Iridium spark plugs, 8 each (12 for 6 cylinder)
  • High energy inductive ignition coil pack with integral magneto block off plate, 2 each (3 for 6 cylinder)
  • Spark plug adapters, 18mm to 14mm, 8 each (12 each for 6 cylinder)
  • EFII ultra compact electronic fuel injector assemblies with weld-in bases, 4 each (6 each for 6 cylinder) (note- customer provides intake tubes for weld-in base installation)
  • EFII modified flywheel with trigger magnets added. (note – customer provides flywheel for modification)
  • Billet Hall effect crank trigger (no case drilling required)
  • Dual fuel pump module
  • Fuel pressure regulator
  • High pressure EFII fuel filter
  • EFII wire harness – All Tefzel harness with sealed waterproof connectors
  • Engine computer – ECU
  • Mechanical fuel pump block off plate
  • Engine temperature sensor
  • MAP sensor
  • EFII throttle body with throttle position sensor, intake air temp sensor, and Lycoming sump adapter
  • Aviation programmer for ECU
  • Tuning adjust knob – for easy system tuning

EFII Kit Options

The majority of our customers prefer full redundancy in their engine systems to ensure the highest degree of safety. To satisfy this demand, we offer a Dual ECU option for the EFII kits. The Dual ECU kits include redundant components on all critical engine management functions including a dual sensor crank trigger, dual MAP sensors, dual IAT sensors and dual ECUs.


  • EFII-4; Electronic Fuel Injection and Dual High Energy Ignition for 4 cylinder Lycoming engines
  • EFII-6; Electronic Fuel Injection and Dual High Energy Ignition for 6 cylinder Lycoming engines
  • EFII-4R; Dual ECU EFII system for 4 cylinder Lycoming
  • EFII-6R; Dual ECU EFII system for 6 cylinder Lycoming
  • EFII-6RCONT; Dual ECU EFII system for Continental 520/550

Call or email for a quote on your system today!