Injector Duty Cycle

The percentage of available time an injector is held open, indicating how close it is to maxing out.

Injector duty cycle (IDC) is the fraction of each engine cycle's available time that the injector is actually spraying, expressed as a percentage. At 100% the injector is static (fully open and flowing no more), and it climbs with RPM and load. IDC matters because injectors that approach or exceed about 85-90% lose the headroom to add fuel, causing the engine to go lean at the top of the power band exactly where lean is most dangerous. Watching IDC tells you when your injectors are undersized for your power level and whether you have safety margin left. In HP Tuners VCM Scanner you can log or compute injector duty cycle and pulse width as channels and watch peak values during WOT pulls. If IDC pegs near 100% while the wideband leans out up top, you need larger injectors, not a fueling table change. Always pair IDC monitoring with a wideband on boosted builds.