K&N Electronic Carburetor Injection, or ECI, is a bolt-on system, via Marken Performance, that adds a supplemental fuel source to your engine. The system consists of a carb spacer plate with a fuel block and injector, an ECU, and a wide band O2 sensor.  When needed, the injector squirts atomized fuel into the air stream passing through the spacer plate solving the fuel delivery issues you may be experiencing with such added benefits as: no priming, no choke, no flooding.  This really helps with easier start ups due to it’s atomization. 

   In a way, the ECI system works like an EFI system that reads the air/fuel ratio from an included O2 sensor that you install in your exhaust.  Where this differs from EFI, is that it is used in conjunction with the carburetor.  Any time the system detects a lean condition, the injector will kick on to bring the AFR back to spec, but the engine is still fed primarily by the carb.  Before you fire the engine for the first time, you answer a few simple questions and set parameters for the system to follow.  One of those parameters is AFR.  If the system detects an AFR higher than the user-defined limit, the weatherproof ECU tells the injector to fire. You can set more parameters like injector pulse width, shot volume, progressive injector firing, and minimum/maximum RPM range in which to operate.  This makes the K&N ECI extremely versatile. 

   Thanks to its supplemental and adaptive design, the K&N ECI system is the perfect middle ground between a straight carburetor and a full EFI system.  Available for Holley 4150, Holley Dominator (comes with 2 injectors), or Quadrajet style carburetor.