Service Manual Owner's manual
Table Of Contents
- Section 1. Specifications
- Section 2. General
- Section 3. Chassis & Turntable
- 3.1 Tires & Wheels
- 3.2 Wheel Drive Assembly, 2WD
- 3.3 Drive Motor - 2WD (Prior to S/N 83331)
- 3.4 Drive Motor (S/N 83331 to Present)
- 3.5 Torque Hub
- 3.6 Wheel Drive Assembly, 4WD
- 3.7 Torque Hub (4WD Machines W/ Integral Brake)
- Roll, Leak and Brake Testing
- Tightening and Torquing Bolts
- Main Disassembly
- Input Carrier Disassembly
- Output Carrier Disassembly
- Housing-Spindle Disassembly
- Spindle-Brake Disassembly
- Input Carrier Sub-Assembly
- Output Carrier Sub-Assembly
- Spindle-Brake Sub-Assembly
- Housing-Spindle Sub-Assembly
- DW2B Integral Brake Check
- Main Assembly
- 3.8 Drive Brake, 2WD - Mico (Prior to S/N 83331)
- 3.9 Re-Aligning torque hub input coupling
- 3.10 Oscillating Axle Bleeding Procedure and Lockout Test
- 3.11 Swing Drive Hub
- 3.12 Swing Brake - Mico (Prior to S/N 66417)
- 3.13 Swing Motor (Prior to S/N 66417)
- 3.14 Swing Motor (S/N 66417 to Present)
- 3.15 Procedure For Setting Gear Backlash
- 3.16 Swing Bearing
- 3.17 Rotary Coupling
- 3.18 Generator
- 3.19 Ford EFI Engine
- 3.20 Deutz EMR 2 (S/N 85332 to Present)
- 3.21 GM Engine General Maintenance
- 3.22 GM Engine Dual Fuel System
- Fuel Filter
- Electric Lock Off
- EPR Assembly
- Low Pressure Regulator (LPR)
- Air Fuel Mixer
- Electronic Throttle Control (ETC)
- Engine Control Module
- Heated Exhaust Gas Oxygen Sensor
- Gasoline Multi Point Fuel Injection System (MPFI)
- Gasoline Fuel Pump
- Gasoline Pressure And Temperature Sensor Manifold
- Fuel Filter
- Fuel Injector Rail
- Fuel Injector
- 3.23 GM Engine Fuel System Repair
- Propane Fuel System Pressure Relief
- Propane Fuel System Leak Test
- Propane Fuel Filter Replacement
- Electronic Pressure Regulator (EPR) Assembly Replacement
- Temperature Manifold Absolute Pressure (TMAP) Sensor
- Electronic Throttle Control Replacement
- Mixer Replacement
- Coolant Hose Replacement
- Vapor Hose Replacement
- Engine Control Module Replacement
- Heated Exhaust Gas Oxygen Sensor Replacement
- 3.24 GM Engine LPG Fuel System Diagnosis
- Section 4. Boom & Platform
- Section 5. Hydraulics
- Section 6. JLG Control System
- Section 7. Basic Electrical information & schematics
SECTION 3 - CHASSIS & TURNTABLE
3121139 – JLG Lift – 3-127
OPEN LOOP AND CLOSED LOOP OPERATION
The ECM will operate in the following two modes:
• Open loop
• Closed loop
When the engine is first started, the system is in "open
loop" operation. In open loop, the ECM ignores the signal
from the heated oxygen sensor (HO2S). it uses a pre-pro-
grammed routine to calculate the air/fuel ratio based on
inputs from the TP, ECT, and MAP sensors.
The system remains in open loop until the following condi-
tions are met:
• The HO2S has a varying voltage output showing that it
is hot enough to operate properly (this depends on
temperature).
• The ECT has reached 160°F (71°C).
• Seven minutes has elapsed since starting the engine.
After these conditions are met, the engine is said to be
operating in "closed loop." In closed loop, The ECM con-
tinuously adjusts the air/fuel ratio by responding to signals
from the HO2S (except at wide-open throttle). When the
HO2S reports a lean condition (low sensor signal voltage),
the ECM responds by increasing the "on" time of the fuel
injectors, thus enriching the mixture. When the HO2S
reports a rich condition (high sensor signal Voltages the
ECM responds by reducing the "on" time of the fuel injec-
tors, thus leaning out the mixture.
CAMSHAFT POSITION (CMP) SENSOR
The CMP sensor uses a variable reactor sensor to detect
camshaft position. The CMP signal is created as piston #1
is a predetermined number of degrees after top dead cen-
ter on the power stroke.
CRANKSHAFT POSITION (CKP) SENSOR
The crankshaft position (CKP) sensor provides a signal
used by the engine control module (ECM) to calculate the
ignition sequence. The sensor initiates the reference
pulses which the ECM uses to calculate RPM and crank-
shaft position.
ELECTRONIC IGNITION
The electronic ignition system controls fuel combustion by
providing a spark to ignite the compressed air/fuel w mix-
ture at the correct time. To provide optimum engine perfor-
mance, fuel economy, and control of exhaust emissions,
the ECM controls the spark advance of the ignition sys-
tem. Electronic ignition has the following advantages over
a mechanical distributor system:
• No moving parts
• Less maintenance
• Remote mounting capability
• No mechanical load on the engine
• More coil cooldown time between firing events
• Elimination of mechanical timing adjustments
• Increased available ignition coil saturation time