2009-2010 Polaris RZR Factory Service Manual, Page 122Get this manual
ELECTRONIC FUEL INJECTION The ECU controls the amount of fuel being injected and the ignition timing by monitoring the primary sensor signals for air temperature, barometric air pressure, engine temperature, speed (RPM), and throttle position (load)These 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
ELECTRONIC CONTROL UNIT (ECU)
Operation Overview