Diesel Engine Operating Range And Shutdown Level

3.7 Engine Operating Range
– Note: Cummins series engines are designed to operate successfully at full throttle up to the maximum torque engine speed (rpm) under transient conditions. This is consistent with recommended operating practices for achieving good fuel economy. Operating the engine at full throttle below the maximum torque speed (the maximum required torque speed varies between 1,100 rpm and 1,500 rpm based on rated engine speed) will shorten the engine’s lifespan, necessitate major repairs prematurely, and can lead to serious engine damage, which is considered abusive to the engine.
– Note: When shifting gears, due to the different gear ratios of the transmission gears, the engine may operate below the maximum torque speed, but the time the engine operates at full throttle below the maximum torque must not exceed one minute.
– Note: Operating the engine at excessively high speeds will cause serious engine damage. When descending steep grades, use a combination of transmission gears and engine or brake to control vehicle and engine speed.

3.8 Engine Shutdown Procedure
1. After operating at full load, allow the engine to idle for 3 to 5 minutes before shutting it down. This allows the engine to gradually and evenly cool down.
2. Turn the ignition key switch to the off position.