... retards the timing in fixed stepsuntil the knock disappears. When the knocking stops, the ECM stopsretarding the ignition timing and begins to advance the timing in fixedsteps. If the ignition ... retards the timing in fixed stepsuntil the knock disappears. When theknocking stops, the ECM stops retardingthe ignition timing and begins to advancethe timing in fixed steps.Fig. 3-23T852f151Fig. ... 3-13T852f142IgnitionIGTAdvancedAngleInitial Ignition Timing 5º, 7º, or 10ºBTDC(Depending on Engine Model)TDC TOYOTA Technical Training3-12Section 3Ignition timing control consists of two basic elements:...