TM-9-2815-220-24 Maintenance Manual for AVDS-1790-2CA AVDS-1790-DA and AVDS-1790-2DR Engines Download
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TM 9-2815-220-24 ENGINE ROUGH OPERATION 0014 00 MALFUNCTION 1: (Continued) Engine misfires (more noticeable at idle operation). PROBABLE CAUSE CORRECTIVE ACTION g. Return fuel line disconnected or restricted. (1) Inspect fuel line (WP 0088, Manifold Heater Assembly and Related Parts Replacement). h. Manifold heater solenoid defective. (1) Check solenoid operation as follows: PROCEDURE OBSERVATION ANALYSIS Evidence of action indicates normal solenoid valve operation. Press heater switch intermittently "ON" and "OFF". Note audible "click" or opening and closing valve action (by touch) of both solenoid valves (fuel supply and fuel return). No audible "click" or action indicates solenoid valve(s) is defective. Fuel flow indicates solenoid valve is operating properly and fuel filters are satisfactory. With switch in "ON" position, note fuel flow from tee opening with each purge pump stroke. No fuel or restricted flow indicates manifold heater filter or felt filters in solenoid valve are restricted or clogged. If fuel flow stops, solenoid valve is closing properly. To Check Solenoid Valve and Fuel Filter: Disconnect one fuel tube from engine front solenoid valve outlet tee, operate purge pump and press heater switch "ON" and "OFF". With switch in "OFF" position note that fuel flow stops. If fuel flow continues, solenoid valve is defective (stuck open). Moderate flow indicates solenoid valve is operating properly and check valve is opening properly. With switch in "ON" position, note fuel flow from check valve opening. No fuel or restricted flow indicates check valve stuck closed or felt filters in solenoid valve are restricted or clogged. If fuel flow stops, solenoid valve is closing properly. To Check Return Fuel Solenoid Valve and Check Valve: Remove fuel return solenoid outlet tube after the check valve at rear of engine, operate purge pump and press heater switch "ON" and "OFF". With switch in "OFF" position, note that fuel flow stops. If fuel flow continues, solenoid valve is defective (stuck in open position). WP 0014 00-3