OM4202 Automatic Lubrication System - Section 42 Page 42-11 SYSTEM TROUBLESHOOTING CHART If the following procedures do not correct the problem, contact a factory authorized service center. POSSIBLE CAUSES SUGGESTED CORRECTIVE ACTION TROUBLE: Pump Does Not Operate Lube system not grounded. Correct grounding connections to pump assembly and truck chassis. Electrical power loss. Locate cause of power loss and repair. 24 VDC power required. Be sure keyswitch is ON. Timer malfunction. Replace timer assembly. Solenoid valve malfunctioning. Replace the solenoid valve assembly. Pump malfunction. Replace pump assembly. No supply pressure. Start the engine. NOTE:
On initial startup of the lube system, the timing capacitor will not contain a charge, therefore the first timing cycle will be about double in length compared to the normal interval. Subsequent timer cycles should be as TROUBLE: Pump Will Not Prime Low lubricant supply. Fill reservoir. Dirt in reservoir, pump inlet clogged. Clean pump and reservoir. Remove source of con- tamination. Pump Jammed. Repair/replace pump assembly. TROUBLE: Pump Will Not Build Pressure Air trapped in lubricant supply line. Prime system to remove trapped air. Lubricant supply line leaking. Check lines and connections to repair leakage. Vent valve leaking. Clean or replace vent valve. Pump cylinder worn or scored.
Repair or replace pump assembly. Reservoir empty. Fill reservoir. Check valves stuck open. Replace check valves. TROUBLE: Injector Indicator Stem Does Not Operate NOTE: Normally, during operation, the injector indicator stem will move into the body of the injector when pressure builds properly. When the system vents (pressure release) the indicator stem will again move out into the adjusting yoke. Malfunctioning injector - usually indicated by the pump building pressure and then venting. Note: Can be caused by overtightened fitting in delivery port of the injector. Replace individual injector assembly. All injectors inoperative - pump build up not sufficient to cycle injectors.
Pump build up not sufficient to cycle injectors. Repair/replace pump assembly. Check pump cylin- der pressure and line pressure at pump. Whole series of injectors inoperative. Check for broken or clogged intermediate supply line and replace.