Table of Contents

Centurion Glossary

  • ECM/ECU (Electronic control module/unit):This is the brain of the motorcycle; it makes calculations based on inputs coming from sensors mounted all over the engine.
  • WOT (Wideopen throttle): The maximum opening of the throttle valve.
  • AFR (Airfuel ratio):The relationship of parts of fuel to the parts of air.13.0(air) to 1(fuel) usually makes the best power, and 14.6 is considered "perfect" air fuel ratio. This would be the AFR to get an ideal burn(theoretically). This would be at perfect atmospheric conditions and temps, with a perfect atomization which is almost impossible.
  • MAP (Manifold absolute pressure): These sensors measure barometric absolute pressure in the intake manifold. By calculating the mass of the air going into the engine, air temperature, and the rotations per minute of the engine, the engine's ECU can determine the density of the air flowing into the fuel mixture. The ECU can then adjust air flow or fuel flow.
  • CKP or CP(Crank position sensor):This sensor tells the ECM when to fire and inject fuel depending on how fast the engine is running in Revolutions Per Minute.
  • IAT (Intake air temperature): The ECM calculates how dense the air is from this input.
  • ET (Engine temperature): The ECM uses the signals from this sensor to determine if the engine is at operating temperature, or warming up.
  • Fuel Pressure Regulator: A mechanical device usually operated by vacuum form intake manifold that controls fuel pressure. It returns excess fuel from the fuel pump back to the fuel tank.
  • Fuel Injectors: The fuel injectors are electric valves that open and close to deliver fuel in spray form to the cylinder. They are controlled by the ECM to precisely deliver the correct amount of fuel at every engine speed or RPM and any given load. The time of injection is also known as the injector "pulse width" and is measured in milliseconds. Injectors are rated by their flow rate such as in gm/sec, l/hr or grams per second.
  • Electric Fuel Pump or Fuel Pump: A 12-volt high-pressure fuel pump, usually located in the fuel tank, but it can be located outside as well. It supplies pressurized fuel to the fuel injectors.
  • IAC (Idle air control): An electric valve that's threaded, to open and close as needed to let air into the engine for startup and idle operation when throttle valve is closed.
  • Closed Loop injection system: This circuit has 2 Oxygen sensors. The information on the difference of how much is coming out of the cylinder is relayed to the ECM and then adjusts the amount of fuel injected by shortening or lengthening the time the injectors are open.
  • O2 (oxygen) sensor: This tells the ECM how much oxygen is in the exhaust mixture so as to have the correct mixture. Anything under 14.7 isconsidered a rich mixture and anything above 14.7 is considered a lean mixture.
  • RPM (Revolutions per minute):Used to measure engine speed.
  • TPS (Throttle position sensor):Measured in percentages (0 to 100) or Degrees and/or Volts (V).
  • DDM (Dropdown menu): Selection of parameters available for a field.