TM 5-3895-383-24 Problem 5:  Engine Stall At Low RPM Probable Cause(s): Fuel Pressure Is Low Low Idle RPM Too Low Engine Accessories Defect In Fuel Injector(s) Fuel Injector Control Linkage Binding Problem With Governor Air In Fuel Combustion Gas, Or Water In Fuel 1. Fuel pressure is low: Make  sure  there  is  fuel  in  the  fuel  tank.    Look  for leaks  or  bad  bends  in  the  fuel  line  between  fuel tank and fuel transfer pump.  Look for air in the fuel system.  Make sure the fuel filters are clean, then check fuel pressure.  The outlet pressure of the fuel transfer pump must be a minimum of 200 kPa (29 psi) at full load speed.  If fuel pressure is lower than the  above  pressure,  check  the  fuel  transfer  pump and fuel pressure regulating orifice at the fuel return line. 2. Low idle rpm too low: Make adjustment to governor so low idle rpm is the same   as   given   in   the   Fuel   Setting   And   Related Information Fiche. 3. Engine accessories: Check  engine  accessories  for  damage  and  make repair or replacement.  If necessary, disconnect the accessories and test the engine. 4. Defect in fuel injector(s): Refer    to    Problem    No.    4,    Engine    Misfiring    Or Running Rough. 5. Fuel injector control linkage binding: Disconnect   the   governor   output   shaft   from   the   fuel injector  control  linkage.    Check  the  linkage  for  smooth operation.  If linkage still appear to be binding, remove injectors.      With   injector   springs   compressed,   check injector  racks  for  smooth  operation.    Replace  injectors with  "sticky"  racks.    Check  linkage  again  for  smooth operation.  If still binding, loosen bolts holding linkage to cylinder head.  Operate the linkage by hand.  If binding is  still  present  after  retightening  the  bolts,  replace  the control linkage. 6. Problem with the governor: Bench test the governor.  If the governor cannot be properly adjusted during bench testing, repair or replace the governor.  Bench test the repaired or replacement governor. 7. Air in fuel: Check   for   inlet   fuel   line   or   transfer   pump   leak. Repair as needed or install new components. 8. Combustion gas, or water in fuel: Check injector sleeve.  Repair as needed or install new components. Problem 6:  Knock Or Miss At Idle Probable Cause(s): Miscalibrated Injector Broken Or Missing Injector Rocker Arm Insert 1. Miscalibrated Injector Determining which injector is causing the misfire or knock can sometimes be difficult on diesel engines. One injector delivering a different quantity of fuel to its  cylinder  can  cause  an  engine  to  produce  an audible misfire or knock at low idle.  Either condition can  contribute  to  idle  instability.    Three  methods which help to find the injector that is delivering an incorrect amount of fuel at idle are listed below. a. With the engine operating at low idle, and at normal jacket  water  operating  temperature,  measure  the exhaust  manifold  temperature  at  each  pot  using 1U8865 Infrared Thermometer.  The temperature of exhaust  Port  1  should  be  within  20C   (40F)   of exhaust Port 6.  The temperature of exhaust Port 2 should  be  within  20C  (40F)   of   exhaust   Port   5. The temperature of exhaust Port 3 should be within 20C (40F) of exhaust Port 4.  If the temperatures are not within 20C (40F), check rack synchronization. 6-36