TUBE ASSEM. (L.H.) 4V8307 - Caterpillar

Fuel ratio control group.Test procedures, adjustments and operation of the fuel ratio control group are given in the Service Manual.
Use the procedure given in the Service Manual, 3406B Truck Engine, Testing And Adjusting Section, to adjust the dynamic fuel ratio control setting correctly. All NSFS fuel ratio controls should be dynamically adjusted.The new fuel ratio control groups are direct replacements for the former groups as shown in Chart A.
The new fuel ratio controls are in effect as shown in Chart B. For engines not shown in Chart B, check the identification tag attached to the control group, for the part number shown in Chart A.
Chart C shows the parts that are different between the new and former fuel ratio control groups.
Unless a failure occurs there is no need to upgrade earlier controls with new components. If a failure does occur, use the diagnostic procedure given in the 3406B Truck Engine Service Manual to determine the cause of the failure. If new parts are needed to repair the fuel ratio control, all of the new parts shown in Chart C should be used together.