2010 Polaris Sportsman 850 Service Manual, Page 57Get this manual
ELECTRONIC FUEL INJECTION ELECTRONIC FUEL INJECTION
General Information
The Electronic Fuel Injection (EFI) system is complete engine fuel and ignition management designThis system includes the following principal components: Fuel PumpFuel FiltersPressure Regulator Fuel Line Fuel Rail Fuel Injectors Throttle Bodylntegrated Air Fuel Manifold (IAFM) Electronic Control Unit (ECU) Ignition Coil Engine Coolant Temperature Sensor (ECT) Throttle Position Sensor (TPS) Crankshaft Position Sensor (CPS) Intake Air TemperatureManifold Absolute Pressure Sensor (T-MAP) Idle Air Control (IAC) Wire Harness Assembly The ECU controls the amount of fuel being injected and the ignition timing by monitoring the primary sensor signals for intake air temperature, manifold absolute pressure (load), engine temperature, speed (RPM), and throttle positionThese primary signals are compared to the programming in the ECU computer chip, and the ECU adjusts the fuel delivery and ignition timing to match the valuesDuring operation the ECU has the ability to re-adjust temporarily, providing compensation for changes in overall engine condition and operating environment, so it will be able to maintain the ideal airfuel ratioDuring certain operating periods such as cold starts, warm up, acceleration, etc richer airfuel ratio is automatically calculated by the ECU