ARMY TM 9-2815-256-24 AIR FORCE TO 38G1-96-2 MARINE CORPS TM 2815-24/5 c. Install nozzle (5) in cylinder head using a slight twisting motion as nozzle is seated in bore. d. Install bolt (4).  Do not tighten bolt (4) at this time. CAUTION Always  use  two  wrenches  when  loosening  or  tightening  fuel  lines  at  nozzles  to  avoid  damage  to equipment. e. Remove caps and connect fuel pressure line to nozzle.  Leave connection slightly loose until air is bled from system. f. Tighten nozzle hold-down bolt (4) to 27 ft-lbs (37 Nm). g. Install leak-off line assembly.  Secure with new grommet (2) and coupling nut (3). h. Bleed fuel system, refer to paragraph 3-23. 3-30. AFTER ENGINE INSTALLATION TESTING. 3-30.1. Test Fuel Injection Noz7les (Engine Running). a. Operate engine at intermediate speed and no load. CAUTION Always  use  two  wrenches  when  loosening  or  tightening  fuel  lines  at  nozzles  to  avoid  damage  to equipment. b. Slowly  loosen  fuel  pressure  line  at  one  nozzle  until  fuel  escapes  at  the  connection  (fuel  not  opening  nozzle valve). c. If  engine  speed  changes,  injection  nozzle  is  probably  working  satisfactory.    If  engine  speed  does  not  change, nozzle is faulty and must be checked and/or replaced. d. Repeat test for each remaining nozzle assembly. e. Remove faulty injection nozzles and replace, refer to paragraph 3-29. 3-30.2. Fuel Drain Back Test. NOTE Fuel draining back through fuel system may cause hard starting.  This procedure will determine if air is entering system at connections and allowing fuel to siphon back to fuel tank. a. Disconnect fuel supply line and fuel return line at fuel tank, refer to end item maintenance manual. CAUTION Fuel return line must extend below fuel level in fuel tank before performing this test.  Fill fuel tank if necessary. 3-137