SECTION 3 - CHASSIS & TURNTABLE
3121160
– JLG Lift –
3-141
Table 3-12. LPF Fuel System Diagnosis
STEP
ACTION
VALUE(S)
YES
NO
1
Were you referred to this procedure by a DTC diagnostic chart?
- -
Go to Step 3
Go to Step 2
2
Perform the On Board Diagnostic (OBD) System Check.
Are any DTCs present in the ECM?
- -
Go to the
applicable DTC Table
Go to Step 3
3
Verify that the LPG fuel tank has a minimum of 1/4 tank of fuel, that the manual
valve is open and the tank quick connect is fully engaged
Does the vehicle have fuel?
- -
Go to Step 4
- -
4
1. Connect a water column gauge or a manometer to the secondary test port of
the low pressure regulator (LPR).
2. Start the engine and allow it to reach operating temperature.
Does the engine start and run?
- -
Go to Step 5
Go to Step 8
5
With the engine idling, observe the pressure reading for the LPR secondary
pressure.
Does the fuel pressure fluctuate rhythmically OUTSIDE the specified range?
-1.0" to
-2.0" w.c
Go to Step 25
Go to Step 6
6
1. Disconnect the EPR electrical connectors. NOTE: This action will cause a
DTC to be set by the ECM
2. With the engine idling observe the pressure reading on the secondary test
port.
Is the fuel pressure WITHIN the specified range?
-1.0" to
-2.0" w.c
Go to Fuel Control
System Diagnosis
Go to Step 7
7
1. Inspect the air intake stream between the mixer assembly and the throttle
body for leaks.
2. Inspect the fuel hose connection between the LPR and mixer assembly for
damage or leakage.
3. Inspect any vacuum hoses for leaks
Was a problem found and corrected?
- -
Go to Step 26
Go to Step 22
8
1. Connect a water column gauge or a manometer to the secondary test port of
the low pressure regulator (LPR).
2. Crank the engine and observe the pressure reading for the LPR secondary
pressure.
Does the fuel pressure indicate a vacuum is present?
- -
Go to Step 12
Go to Step 9
9
1. Remove Air induction hose to the mixer
2. Observe the air valve for movement while the engine is cranking. Note: Move-
ment of the air valve will be minimal at cranking speeds.
Does the air valve move when the engine is cranked?
- -
Go to Step 11
Go to Step 10
10
1. Inspect the air intake stream to the mixer assembly and the throttle body for
vacuum leaks.
2. Inspect the vacuum hoses from the mixer for proper connection and condition.
Was a problem found and repaired?
- -
Go to Step 26
Go to Step 24
11
Inspect the fuel hose connection between the LPR and the mixer assembly for
damage or leakage.
Was a problem found and repaired?
- -
Go to Step 26
Go to Step 12
12
1. Connect a 0-10 psi gauge to the primary test port of the low pressure regulator
(LPR).
2. Crank the engine and observe the pressure reading for the LPR primary pres-
sure.
Is the fuel pressure ABOVE the specified value?
1- 3 PSI
Go to Step 22
Go to Step 13
Summary of Contents for 740A
Page 1: ...Service and Maintenance Manual Models 740A 740AJ P N 3121160 January 8 2013 ...
Page 2: ......
Page 52: ...SECTION 2 GENERAL 2 12 JLG Lift 3121160 NOTES ...
Page 109: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 57 Figure 3 39 Swing Hub ...
Page 135: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 83 Figure 3 48 Rotary Coupling Port Location ...
Page 153: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 101 Figure 3 54 EFI Component Location ...
Page 156: ...SECTION 3 CHASSIS TURNTABLE 3 104 JLG Lift 3121160 Figure 3 55 ECM EPM Identification ECM EPM ...
Page 173: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 121 Figure 3 65 EMR2 Fault Codes Sheet 1 of 5 ...
Page 174: ...SECTION 3 CHASSIS TURNTABLE 3 122 JLG Lift 3121160 Figure 3 66 EMR2 Fault Codes Sheet 2 of 5 ...
Page 175: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 123 Figure 3 67 EMR2 Fault Codes Sheet 3 of 5 ...
Page 176: ...SECTION 3 CHASSIS TURNTABLE 3 124 JLG Lift 3121160 Figure 3 68 EMR2 Fault Codes Sheet 4 of 5 ...
Page 177: ...SECTION 3 CHASSIS TURNTABLE 3121160 JLG Lift 3 125 Figure 3 69 EMR2 Fault Codes Sheet 5 of 5 ...
Page 244: ...SECTION 4 BOOM PLATFORM 4 28 JLG Lift 3121160 Figure 4 14 Rotator Assembly HELAC ...
Page 286: ...SECTION 4 BOOM PLATFORM 4 70 JLG Lift 3121160 NOTES ...
Page 307: ...SECTION 5 HYDRAULICS 3121160 JLG Lift 5 21 Figure 5 17 Variable Displacement Pump Rexroth ...
Page 316: ...SECTION 5 HYDRAULICS 5 30 JLG Lift 3121160 NOTES ...
Page 319: ...SECTION 6 JLG CONTROL SYSTEM 3121160 JLG Lift 6 3 Figure 6 2 ADE Block Diagram ...
Page 328: ...SECTION 6 JLG CONTROL SYSTEM 6 12 JLG Lift 3121160 Figure 6 11 Control Module Location ...
Page 374: ...SECTION 6 JLG CONTROL SYSTEM 6 58 JLG Lift 3121160 NOTES ...
Page 406: ...SECTION 7 BASIC ELECTRICAL INFORMATION SCHEMATICS 7 32 JLG Lift 3121160 NOTES ...
Page 407: ......