NOZZLE AS-FUEL VALVE 7C2238 - Caterpillar

Adjustment of the governor gains may be necessary for stable engine operation.For generator set engines there are two sets of gains available:
Primary governor gains
Auxiliary governor gainsNote: For industrial engines only the primary set of gains are available.The primary governor gains are used to provide engine stability for the synchronization of (off-grid) applications.The auxiliary governor gains are used to provide engine stability for (on-grid) applications.Note: The primary (off-grid) governor gain maps are different from the auxiliary (on-grid) governor gain maps. For this reason the proper wiring of the "Grid Status" switch is mandatory.The "Grid Status" switch input controls the "Grid Status" parameter that is viewable on Cat ET."Grid Status" has two states: "On" and "Off" of the grid. When, the "Grid Status" switch input is grounded the "Grid Status" is "On" the grid.Primary governor gains for (off-grid) applications:
"Governor (Proportional) Gain Percentage"
"Governor (Integral) Stability Percentage"Auxiliary governor gains for (on-grid) applications:
"Governor Auxiliary 1 (Proportional) Gain Percentage"
"Governor Auxiliary 1 (Integral) Stability Percentage"The default values should be sufficient for initial start-up. However, the values may not provide optimum performance.These adjustments are provided in order to obtain optimum responses to changes in the load and in the speed. The adjustments also provide stability during steady state operation.If you have a problem with instability, always investigate other causes before you adjust the governor. For example, diagnostic codes and unstable gas pressure can cause instability.To change the parameters, use the "Real Time Graphing" feature on the "Information" drop-down menu of Cat ET. The graph provides the best method for observing the effects of your adjustments.For details on these parameters, refer to Systems Operation/Testing and Adjusting, "Electronic Control System Parameters". After you make adjustments, always test the stability by interrupting the engine speed and/or load. Operate the engine through the entire range of speeds and of loads in order to ensure stability.Note: Adjustment of the "Governor (Proportional) Gain Percentage" directly affects the speed of the throttle actuator during the correction between the actual engine speed and the desired engine speed. An excessive increase of this parameter may amplify instability.To set the "Governor (Proportional) Gain Percentage", increase the value until the actuator becomes unstable. Slowly reduce the value in order to stabilize the actuator. Observe that the engine operates properly with little overshoot or undershoot.The adjustment of "Governor (Integral) Stability Percentage" dampens the throttle actuator response to changes in load and in speed. Increasing this value provides less damping. Decreasing the value provides more damping. In order to adjust, perform the following:
To reduce overshoot, increase the value.
To reduce undershoot, decrease the value.Note: An increase of the "Governor (Integral) Stability Percentage" may require a decrease of the "Governor (Proportional) Gain Percentage" in order to maintain a stable operation.Illustration 1 shows some typical curves for transient responses.
Illustration 1 g01017530
(Y) Engine speed
(X) Time
(1) The "Governor (Proportional) Gain Percentage" is too