Doosan G420F G420FE Engine Service Manual LP Dual Fuel Forklift PDF

Description

Doosan G420F G420FE Engine Service Manual LP Dual Fuel Forklift – PDF DOWNLOAD

DESCRIPTION

This comprehensive Doosan G420FE and G420F Engine Service Manual (Document SB4241E00, April 2007) provides complete technical documentation for servicing and repairing LP/dual fuel and LP/gasoline engines used in Doosan industrial forklifts. This professional-grade manual is essential for certified technicians, fleet maintenance personnel, and authorized service centers working on EPA 2007 compliant forklift power plants.

Engine Models Covered

G420FE Engine – EPA/CARB 2007 Emission Regulation Compliant

• LP/Dual Fuel configuration with electronic control
• Closed loop LP carburetion system
• Closed loop MPI gasoline system
• 3-way catalytic muffler standard

G420F Engine – Standard LP/Gasoline/Dual Fuel System

• Electronic control by ECM
• Open loop LP carburetion system
• Closed loop MPI gasoline system
• Standard muffler (without catalyst)

Forklift Models Covered

Small Capacity Series:

• G15S-5, G18S-5, G20SC-5 (Standard cushion tire)
• GC15S-5, GC18S-5, GC20SC-5 (Cushion tire counterbalance)

Large Capacity Series:

• G20E-5, G25E-5, G30E-5 (Standard pneumatic tire)
• GC20E-5, GC25E-5, GC30E-5, GC33E-5 (Pneumatic tire counterbalance)

Engine Specifications

General Description:

• Engine Type: Water-cooled, inline 4-cycle, 4-cylinder
• Displacement: 1,975 cc (120.5 cubic inches)
• Bore x Stroke: 82mm (3.23 in) x 93.5mm (3.68 in)
• Compression Ratio: 9.4:1
• Valve Configuration: DOHC, 4 valves per cylinder
• Valve Lifter: Hydraulic lash adjuster with intake/exhaust rotator
• Camshaft Drive: Timing belt system (25.4mm toothed belt)
• Firing Order: 1-3-4-2
• Engine Rotation: Counter-clockwise (CCW) from flywheel end
• Dry Weight: 170 kg

Power Output:

• G15S/G18S Models: 33.6 kW (45 hp) @ 2,400 rpm
• G20E/G25E/G30E Models: 39.5 kW (53 hp) @ 2,550 rpm
• Maximum Torque: 147-160 N-m (108-118 lb-ft) @ 1,600 rpm
• Governed Speed: 2,450-2,600 rpm
• Low Idle: 750 rpm

Chapter 1: General Information

Safety Precautions:

• Comprehensive safety warnings and NOTICE labels
• Proper tools and equipment requirements
• Technical competence requirements
• Catalytic converter precautions

Technical Data:

• Tightening torque tables (M5 through M24 bolts)
• Recommended lubricants: API SJ or above, SAE 10W30 or 5W30
• Engine oil capacity: 4.0L (including 0.3L filter)
• Coolant capacity: 8.5L total (3.0L engine, 5.5L radiator/hoses)
• Antifreeze concentration: 50% normal, 40% tropical
• Engine model and serial number identification

Power and Torque Charts:

• Complete performance data for all forklift models
• LP, gasoline, and dual fuel configurations
• Rated power, maximum torque, and governed speed specifications

Chapter 2: Recommended Maintenance

General Maintenance Procedures:

• Fuel system leak testing with approved solutions
• Engine fluid leak inspection protocols
• Vacuum line and fitting inspection
• Electrical system connector checks
• Foot pedal operation verification

Engine Oil Service:

• API classification guide and SAE viscosity selection
• Oil level checking procedures
• Oil and filter replacement intervals
• Proper disposal requirements

Compression Testing:

• Standard compression: 15 kg/cm² (14 kg/cm² limit)
• Cylinder-to-cylinder differential: 1.0 kg/cm² maximum
• Wet vs. dry compression testing procedures
• Troubleshooting worn pistons, rings, valves

Timing Belt Adjustment:

• Tension specifications and measurement
• Deflection limits and adjustment procedures

Cooling System Maintenance:

• Coolant recommendation and concentration testing
• Coolant level checks and hose inspection
• Leak detection procedures
• Specific gravity testing
• Coolant concentration vs. specific gravity charts
• Drive belt checking and adjustment procedures
• Belt damage inspection criteria

Ignition System Maintenance:

• Battery system inspection
• Ignition timing inspection procedures
• Spark plug inspection and gap specifications (0.8mm)
• Platinum spark plug replacement

Fuel System Maintenance:

• LP fuel filter element replacement (40 microns maximum)
• Fuel lock-off operation testing
• Pressure regulator/converter inspection (N-2007 and N-2001)
• Air/fuel valve mixer assembly inspection
• Intake leak detection
• Throttle assembly inspection
• TMAP sensor checking

Exhaust System:

• Exhaust leak inspection procedures
• Catalytic converter service

Maintenance Schedule:

• Comprehensive interval-based maintenance chart

Chapter 3: Engine Mechanical System

General Information:

• Engine outline diagrams
• Complete specifications tables
• Torque specifications for all fasteners
• Special tools required with part numbers
• Troubleshooting flowcharts

Timing Belt System:

• Component identification and layout
• Removal procedures with timing mark alignment
• Inspection criteria for belt wear and damage
• Assembly procedures with proper tensioning
• Timing mark verification

PCV Valve:

• Operation principle and functional description
• Service procedures and replacement

Intake and Exhaust System:

• Intake manifold removal and installation (aluminum with injector ports)
• Exhaust manifold service (cast iron, dry type)
• Gasket replacement procedures

Cooling System:

• System description and operation
• Testing and adjusting procedures
• Coolant pipe and hose routing
• Water pump service (V-belt drive, clockwise rotation)
• Thermostat testing (opening: 82°C, fully open: 95°C)

Cylinder Head Assembly:

• Complete disassembly procedures
• Valve train component inspection
• Cylinder head resurfacing specifications
• Valve seat insert service
• Assembly with proper torque sequences

Lubrication System:

• System description and oil flow diagrams
• Testing and adjustment procedures
• Oil pressure specifications: 167 kPa (24 psi) @ low idle
• Oil temperature ranges: 80°C minimum, 125°C maximum, 99-110°C recommended
• Oil pressure switch testing
• Front case and oil pump service
• Oil pump clearance specifications

Camshaft, HLA, Timing Chain:

• Component identification
• Removal procedures with proper timing
• Hydraulic lash adjuster inspection and testing
• Camshaft bearing clearances
• Timing chain wear measurement

Crankshaft Service:

• Main bearing clearance specifications
• Crankshaft runout and wear limits
• Journal diameter measurements
• Thrust bearing clearances

Flywheel and Housing:

• Flywheel runout specifications
• Housing alignment verification
• Bolt torque specifications

Piston and Connecting Rod:

• Piston-to-cylinder clearances
• Ring gap specifications and installation
• Connecting rod bearing clearances
• Piston pin clearances
• Assembly procedures with ring positioning

Cylinder Block:

• Cylinder bore measurement and wear limits
• Deck surface flatness specifications
• Main bearing bore alignment

Chapter 4: Engine Electrical System

Specifications:

• Complete electrical system specifications
• Voltage and resistance values

Ignition System:

• Coil-on-plug (COP) distributorless ignition
• Electronic control by ECM
• Component identification and location
• Ignition timing inspection procedures
• Ignition coil driver (power transistor) testing
• Ignition coil inspection and resistance testing
• Spark plug inspection (platinum type, 0.8mm gap)
• 12V operation, 4 coils system

Charging System:

• General description and operation
• Troubleshooting procedures and flowcharts
• Alternator specifications: 13.5V, 90 amp output
• Disassembly and installation procedures
• Voltage regulator testing
• Stator and rotor testing

Starting System:

• General description
• Diagnosis procedures with test flowcharts
• Start relay testing procedures
• Troubleshooting no-crank conditions
• Starter motor specifications: 12V, 1.7 kW
• Starter removal and installation

Chapter 5: Engine Management System (EMS)

General Information:

• System specifications
• Service standards
• Component location diagrams

G420FE EMS Overview:

• General system description
• Electronic control architecture
• LPG fuel system operation with closed loop control
• MPI gasoline system operation with closed loop control
• Electronic throttle system (drive-by-wire)
• Ignition system control
• Exhaust system with 3-way catalyst
• SECM (Simplified Engine Control Module) functions

SECM Wiring Diagrams:

• Complete wiring schematics for G420FE
• Connector pin-outs
• Signal flow diagrams

G420F EMS Overview:

• System description for non-EPA version
• LPG fuel system operation with open loop control
• MPI gasoline system operation
• Electronic throttle system
• Ignition system
• Exhaust system without catalyst
• SECM functions

SECM Wiring Diagrams for G420F:

• Complete electrical schematics
• Sensor and actuator connections

EMS Inspection and Repair:

• Engine Control Module (SECM) testing and replacement
• Camshaft position sensor (Hall sensor type)
• Crankshaft position sensor (magnetic inductive type)
• MAP (Manifold Absolute Pressure) sensor testing
• IAT (Intake Air Temperature) sensor verification
• Oxygen sensor testing – Pre-catalyst (gasoline dual fuel system)
• Oxygen sensor testing – Post-catalyst (dual oxygen sensor system)
• ECT (Engine Coolant Temperature) sensor for ECM
• ECT sensor for gauge on instrument panel
• LP fuel temperature sensor
• Accelerator angle sensor (two-output signals in pedal)
• Transmission oil temperature switch
• Ground speed limit switch (optional feature)
• Electronic throttle body with TPS (throttle position sensor)

Chapter 6: LPG Fuel Delivery System

G420FE LP System:

• System removal and installation procedures
• Hose connection routing diagrams
• N-2007 regulator removal and installation (two-stage negative pressure type)
• CA100 mixer removal and installation (diaphragm type air valve, downdraft)
• Testing and adjustment procedures
• N-2007 regulator service testing
• AVV (Air Valve Vacuum) testing procedures
• MI-07 service tool connection
• Idle mixture adjustment with dual dither system
• Fuel trim valve (FTV) dual dither system operation
• Parts description with exploded diagrams
• CA100 mixer component breakdown
• N-2007 regulator specifications

G420F LPG System:

• Removal and installation procedures
• Fuel system connection diagrams
• N-2001 regulator/converter service (two-stage negative pressure)
• CA100 mixer for G420F specifications
• Testing and adjustment procedures
• N-2001 regulator service testing
• AVV testing without FTV
• MI-07 service tool procedures
• Idle mixture adjustment for open loop system
• Parts descriptions and exploded views

Chapter 7: MPI Gasoline Fuel Delivery System

Specifications:

• Fuel pressure: 3.5 bar
• Injector specifications: 12V electric

Special Tools:

• Required tools with part numbers
• Fuel pressure test equipment

Components Location:

• In-tank fuel pump module layout
• Fuel filter and strainer positioning
• Gasoline pressure regulator
• Electric fuel injector locations

Fuel Pressure Test:

• Test procedures and pressure specifications
• Diagnostic procedures for low/high pressure
• Fuel pump performance verification

Fuel Injector:

• Injector removal and installation
• Electrical connector procedures
• O-ring replacement

Injector Inspection:

• Resistance testing
• Spray pattern evaluation
• Flow rate testing
• Cleaning procedures

Fuel Pump:

• In-tank electric fuel pump (12V)
• Removal and installation procedures
• Electrical testing
• Fuel strainer service

Chapter 8: Basic Troubleshooting

Preliminary Checks:

• Before starting inspection checklist
• Visual/physical inspection procedures
• Safety precautions

Basic Troubleshooting Guide:

• Customer problem analysis sheet
• Basic inspection procedure flowcharts
• Connector inspection procedures
• Pin-out diagrams for all connectors
• Continuity and resistance testing

Symptom Troubleshooting Chart:

• Comprehensive symptom-based diagnostic guide
• Probable causes and solutions

Specific Troubleshooting Procedures:

• Intermittents: Detection and diagnosis methods
• Surges and/or Stumbles: Fuel system, ignition, and sensor testing
• Engine Cranking but Will Not Start/Difficult to Start: Fuel delivery, spark, compression checks
• Lack of Power/Slow Response: Fuel pressure, air intake, exhaust restriction testing
• Poor High Speed Performance: Governor settings, fuel delivery, ignition timing
• Hesitation During Acceleration: Throttle body, fuel trim, sensor verification

Key Features & Technical Highlights

✓ EPA 2007 Compliant Documentation – Complete service information for emission-certified engines
✓ Dual Fuel Capability – Service procedures for LP, gasoline, and dual fuel configurations
✓ Electronic Engine Management – Comprehensive EMS diagnostics and repair
✓ Drive-by-Wire System – Electronic throttle body service and calibration
✓ Closed Loop Fuel Control – Advanced fuel trim and oxygen sensor systems
✓ Distributorless Ignition – Coil-on-plug system with electronic control
✓ DOHC 16-Valve Design – Hydraulic lash adjuster service procedures
✓ Timing Belt System – Complete removal, inspection, and installation procedures
✓ Catalytic Converter Service – 3-way catalyst maintenance and testing
✓ MI-07 Service Tool – Diagnostic tool connection and usage procedures

File Details

Manual Name: Doosan G420FE/G420F LP/Dual Fuel Engine Service Manual
Document Number: SB4241E00
Publication Date: April 2007
Manufacturer: Doosan Industrial Vehicle
Models Covered: G15S-5, G18S-5, G20SC-5, GC15S-5, GC18S-5, GC20SC-5, G20E-5, G25E-5, G30E-5, GC20E-5, GC25E-5, GC30E-5, GC33E-5
Total Pages: 326 pages
PDF Quality: High-quality factory manual with searchable text
File Size: 13.7 MB
Format: Fully searchable PDF with diagrams and illustrations