Injected Twin Cam High Temperature Idle

Fuel injected Twin Cam engines use a three phase heat management system to reduce engine temperature under extreme conditions. A rider with a very hot engine may notice the affects of this three phase heat management system and incorrectly assume an idle problem exists.

Phase 1: When the engine temperature sensor signals that the cylinder head has reached approximately 320° F (160° C) the ECM will gradually reduce engine idle speed until the engine temperature drops or the engine reaches 800 RPM.
Phase 2: If engine temperature reaches 338° F (170° C), the ECM richens the air/fuel ratio to provide additional cooling.
Phase 3: If the engine temperature reaches 356° F (180° C), fuel injector pulses are interrupted. The air drawn in and expelled helps cool the engine further. Since there is no combustion it would be perceived as a misfire. This third stage will only happen when the motorcycle is stationary.