2004 Skidoo ZX Series Service Manual, Page 344Get this manual
Section 07 ENGINES MANAGEMENT (4-TEC) Subsection 01 (OVERVIEW)
Electronic Fuel Injection
The ECM reads the signals from different sensors which indicate engine operating conditions at millisecond intervalsSignals from sensors are used by the ECM to determine the injection parameters (fuel maps) required for optimum air-fuel ratioThe CPS, the ATS, the MAPS and the TPS are the primary sensors used to control the injection and ignition timingOther sensors (like temperature sensors, etc are used for secondary input
Ignition Timing
The ECM is programmed with data (it contains ignition mappings) for optimum ignition timing under all operating conditionsUsing engine operating conditions provided by the sensors, the ECM controls the ignition timing for optimum engine operation.There is no mechanical adjustment to perform
Engine Modes of Operation