VALVE GP-RELIEF 4237707 - Caterpillar

System Operation Description:The Electronic Control Module (ECM) has two throttle inputs and two engine synchronization inputs. The engine synchronization inputs allow the ECM to respond to either of the throttle inputs. This capability allows all of the engines on a vessel to respond to a single throttle. This minimizes variations in speed and in load between engines during cruise operations.Use this procedure in order to troubleshoot any suspect problems with engine synchronization. The following items can cause problems with engine synchronization:
Configuration parameters
Vessel wiring or components
ECMThe following configuration parameters affect engine synchronization:
Number of synchronized engines configuration
Engine location
Secondary throttle enable statusThese parameters must be programmed correctly in order for the engines to become synchronized. Refer to Troubleshooting, "System Configuration Parameters" for additional information on these parameters.The engine synchronization inputs operate according to the following conditions:When neither of the engine synchronization inputs are connected to the −Battery, the ECM will respond to the input for the primary throttle.When sync input 1 is connected to the −Battery, the ECM will respond to the input for the primary throttle input.When sync input 2 is connected to the −Battery, the ECM will respond to the input for the secondary throttle.If sync input 1 and sync input 2 are connected to the −Battery at the same time, the ECM will respond to the input for the primary throttle. The vessel's wiring should be designed to prevent this condition from occurring.Note: The ECM will not transfer control between the throttle inputs unless the throttle inputs are within 50 rpm of each other.There are four possible configurations for engine synchronization. The following information describes each configuration.Single Engine Configuration
Illustration 1 g01130005
Single engine configurationIn this configuration, a single engine can be controlled by two throttles. The secondary throttle is enabled by activation of the "Secondary Throttle Enable" switch.Twin Engine Configuration
Illustration 2 g01130061
Twin engine configurationIn this configuration, the position of the synchronization switch determines the throttle input that is recognized by each engine. Table 1 lists the engine's response to each position of the switch.
Table 1
Engine Response to the Synchronization Switch    
Position of the Synchronization Switch    Engine Response    
Starboard     Both engines respond to the starboard throttle.    
None     Each engine responds to