SECTION 3 - CHASSIS & TURNTABLE
3-202
3121160
Exhaust System Checks
² Check the exhaust system for a possible restriction:
- Inspect the exhaust system for damaged or collapsed pipes
- Inspect the muffler for signs of heat distress or for possible internal failure.
² Check for possible plugged catalytic converter. Refer to Restricted Exhaust System Diagnosis
Hard Start
DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may start but immediately dies.
Preliminary Checks
² Refer to Important Preliminary Checks.
² Make sure the vehicle's operator is using the correct starting procedure.
Sensor Checks
²Check the Engine Coolant Temperature sensor with the scan tool. Compare the engine coolant temperature with the ambient air temperature
on a cold engine. IF the coolant temperature reading is more than 5 degrees greater or less than the ambient air temperature on a cold engine,
check for high resistance in the coolant sensor circuit. Refer to DTC 111
² Check the Crankshaft Position (CKP) sensor.
²Check the Throttle position (TPS) sensor.
Fuel System Checks
Important: A closed LPG manual fuel shut off valve will create an extended crank OR no start condition.
² Verify the excess flow valve in the LPG manual shut-off valve is not tripped.
² Check mixer module assembly for proper installation and leakage.
² Verify proper operation of the low pressure lock-off solenoids.
² Verify proper operation of the EPR
² Check for air intake system leakage between the mixer and the throttle body.
² Check the fuel system pressures. Refer to the Fuel System Diagnosis.
Ignition System Checks
Note: LPG being a gaseous fuel requires higher secondary ignition system voltages for the equivalent gasoline operating conditions.
² Check for the proper ignition voltage output with J 26792 or the equivalent.
² Verify that the spark plugs are correct for use with LPG (R42LTS)
² Check the spark plugs for the following conditions:
- Wet plugs
- Cracks
- Wear
- Improper gap
- Burned electrodes
- Heavy deposits
² Check for bare or shorted ignition wires.
² Check for moisture in the distributor cap if applicable.
² Check for loose ignition coil connections.
Important:
1. If the engine starts but then immediately stalls, Check the Crankshaft Position (CKP).
2. Check for improper gap, debris or faulty connections.
Engine Mechanical Checks
Important: The LPG Fuel system works on a fumigation principle of fuel introduction and is more sensitive to intake manifold leakage than the
gasoline fuel supply system.
² Check for the following:
- Vacuum leaks
- Improper valve timing
- Low compression
- Bent pushrods
- Worn rocker arms
- Broken or weak valve springs
- Worn camshaft lobes.
² Check the intake and exhaust manifolds for casting flash.
Exhaust System Checks
² Check the exhaust system for a possible restriction:
- Inspect the exhaust system for damaged or collapsed pipes
- Inspect the muffler for signs of heat distress or for possible internal failure.
² Check for possible plugged catalytic converter. Refer to Restricted Exhaust System Diagnosis or Exhaust System in the GM Base Engine Service
Manual
Table 3-15. Symptom Diagnosis
Checks
Action
Summary of Contents for 740AJ
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Page 116: ...SECTION 3 CHASSIS TURNTABLE 3 64 3121160 Figure 3 44 Swing Hub Prior to SN 0300074383...
Page 203: ...SECTION 3 CHASSIS TURNTABLE 3121160 3 151 Figure 3 77 EFI Component Location...
Page 206: ...SECTION 3 CHASSIS TURNTABLE 3 154 3121160 Figure 3 78 ECM EPM Identification ECM EPM...
Page 224: ...SECTION 3 CHASSIS TURNTABLE 3 172 3121160 Figure 3 83 Deutz EMR 2 Troubleshooting Flow Chart...
Page 228: ...SECTION 3 CHASSIS TURNTABLE 3 176 3121160 Figure 3 87 EMR 2 Engine Plug Pin Identification...
Page 229: ...SECTION 3 CHASSIS TURNTABLE 3121160 3 177 Figure 3 88 EMR 2 Vehicle Plug Pin Identification...
Page 230: ...SECTION 3 CHASSIS TURNTABLE 3 178 3121160 Figure 3 89 EMR2 Fault Codes Sheet 1 of 5...
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Page 303: ...SECTION 4 BOOM PLATFORM 3121160 4 31 Figure 4 20 Rotator Assembly HELAC...
Page 460: ...SECTION 5 BASIC HYDRAULIC INFORMATION AND SCHEMATICS 5 116 3121160 NOTES...
Page 467: ...SECTION 6 JLG CONTROL SYSTEM 3121160 6 7 Figure 6 2 ADE Block Diagram...
Page 534: ...SECTION 6 JLG CONTROL SYSTEM 6 74 3121160 NOTES...
Page 580: ...SECTION 7 BASIC ELECTRICAL INFORMATION SCHEMATICS 7 46 3121160 NOTES...
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