TM-9-2320-387-24 HMMWV Direct Support & General Support Maintenance Manual Volume 1 Download
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TM 9-2320-387-24-l -- REFERENCE INFORMATION Watch the fuel pump pressure while slowly accelerating the engine from idle to maximum speed. The pressure should always be greater than zero. If you can drive the vehicle while measuring the pressure, check to be sure it is still above zero even during maximum acceleration (maximum engine power). You can use STUICE-R test 24 with control function 02 (minimum). NOTE Rapidly accelerating the engine with the transmission in neutral doesn’t work for this engine because the fuel supply can’t increase as fast as the engine can accelerate so you won’t get good test results. Proper engine performance depends upon the availability of the correct fuel volume to the injection pump. Pay attention to when the engine runs rough. If it runs rough only while warming up after a cold start, it may be a glow plug problem and you should run the Glow Plug Circuit tests. Rough running may also be caused by air leaks in the fuel supply lines. Air in the fuel should purge itself while idling. If rough running occurs after a period of high speed or high power running but seems to go away after idling, then look for air leaks in the fuel supply lines and fittings. If rough running occurs while driving but idles ok, check the fuel return check valve for any malfunctions (para. 3-36). Try to adjust the engine idle speed by turning the idle speed screw (para. 3-45). Continue testing if you can adjust the speed property. If you cannot, notify DS maintenance (chapter 14). Engine must be at normal operating temperature when making speed checks. Air filter must be in place and all accessories (lights, heater fan, etc.) must be turned off. Thts engme has a min-max governor which controls engine speed at both idle and full thronle. FUEL SYSTEM I FUEL PUMP VOLUME TEST 1. Disconnect fuel line at injection pump inlet and route fuel line into a suitable 1 quart (1 liter) container. I 2. Crank the engine for 30 seconds. 3. If the pump and lines are ok, you should gE about 1 pint (l/2 quart) (.5 L) in 30 second5 FUEL PUMP PRESSURE STE/lCE-R TEST 24 (SLUICE already connected to DCA and turned on) 1. Select Fuel Supply Pressure test, Test 24. 2. Perform CAL. 3. Crank (or start) the engine. NOTE : STE/ICE-R can display a pressure below 0. Be sure to notice if the display is negative. I FUEL PUMP PRESSURE TEST PRESSURE GAUGE 1. Connect a tee into the fuel line between the fuel filter outlet and the injection pump inlet. 2. Attach gauge to tee. 3. Crank (or start) engine. ENGINE RPM STEIICE-R TEST 10 1. Start Test 10. Engine RPM. 2. Crank or start the engine. Displayed reading is RPM. Cranking rpm should be at least 100 rpm. Idle rpm should be 700-750. 2-103