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 If the engine cranks ok (or starts), then the batteries are good enough for testing the glow plugs. If the engine starts, shut it off. You can use STEXE Test 10 to measure cranking speed. The engine should crank at least 100 rpm in cold weather and at least 180 rpm in warm weather. GLOW PLUGS CIRCUIT NOTE The WAIT-TO-START lamp is NOT diagnosed in this section. If the lamp does not work properly, the glow plug circuit may be affecting Its operation. Run these tests to check out the glow plug circuit. If the lamp still does not work properly, go to the INSTRUMENT section for a full diagnosis of the lamp’s problem. WARNING Disconnect negative battery cable before disconnecting and reconnecting PCB harness. WARNING There is battery voltage at the PCB at all times. Failure to disconnect battery cable will result in damage to equipment or injury to Personnel. BAD CONNECTIONS ARE THF MOST COMMON PROBLEM ! Sometimes just disconnecting, cleaning, and reconnecting will solve a problem. BE THOROUGH! The time you save may be your own. Refer to the functional flow schematic and check the following: 1. BAlTERY - make sure all connections are clean and tight. including the shunt and power stud. 2. PROTECTIVE CQNTROL BOX - remove BOTH connectors and look for bent or broken pins, pins pushed out of their socket. or dirt and corrosion in the connections. 3. GLOW PLUG CONTROLLER - pop the controller connector off (squeeze the sides) and check the pins in both the controller and the connector. Look for bent. broken or pushed out pins, die, or corrosion. Check for broken wires at the connector. Take note that pin 2 of the glow plugs controller connector has no pin in it. 4. GLOW PLUGS - check that all the glow plug wires are snug. Don’t just look with your eyes. Many problems are solved by looking with your fingers to be sure a connection is snug. NORMAL GLOW PLUG OPERATION The glow plugs first come ON when the engine temperature is below 120 “F (49°C) and the rotary switch is turned lo RUN. They stay ON for up to 9 seconds and then go OFF. They will stay OFF for about 7-15 sewnds then come ON CONTROLLER HARNESS again for about 1 second. NOTE BAlTERY CURRENT MULTIMETER 1. Set the voltmeter to a DC volts scale of about 1 volt. 2. Connect the BLACK lead to the battery side of the current shunt and the RED lead to the other end of the current shunt. 3. Current shunt voltage is proportional lo battery current, 100 millivolts = 1,000 amps. To get current, multiply millivolts x 10. I BAlTERY CURRENT STEIICE-R TEST 80 I To check for glow plug current draw, start STE/lCE-R Test 80, Battery Current. Turn off all accessories (lights, heater, wipers, etc.). STE/ICE-R should immediately measure at least 74 amps. Take note, however, that if all your glow plugs are working, the current draw should be close to or more than 100 amps, especially if it’s cold. If it’s near freezing and the glow plugs only draw 75-60 amps, you probably have a few bad glow plugs. 2-291