Installation Method for ISUZU 24V Generator

I. Pre-installation Preparation

1. Vehicle Status & Safety Precautions

• Park the vehicle firmly, engage the parking brake, shift to neutral/parking gear, and disconnect the negative terminal of the 24V battery to prevent short circuits.

• Wait for the engine to cool down completely to avoid scalding.

2. Tools & Accessories

3. Component Inspection

• Verify that the generator model is compatible with the ISUZU engine. Check that the carbon brushes, rectifier, and bearings are in good condition with no leakage.

• Check the labels of wiring terminals: B+ (main output), D+ (excitation), W (speed signal), GND (ground), etc.

II. Detailed Installation Steps

1. Removal of the Old Generator

1. Use a belt tensioner tool to loosen the belt, remove it, and mark its routing direction.

2. Disconnect the generator wiring harness connector and the B+ terminal cable, and clearly mark the corresponding relationship between terminals and wires.

3. Remove the fixing bolts and adjusting arm bolts of the generator, then take off the old unit.

4. Clean oil stains, rust, and debris from the mounting surface. Check if the bracket and shock absorbers are intact; replace them if necessary.

2. Installation of the New Generator

1. Place the new generator into the mounting position, install the fixing bolts and adjusting arm bolts, pre-tighten them without final tightening to reserve adjustment allowance.

2. Connect the wiring harness connector and B+ cable according to the marks. Add lock washers to the terminals and tighten them to the specified torque (usually 12–18 N·m). Protect the B+ wire with an insulating sleeve.

3. Install the belt following the original routing direction. Adjust the tension with a tensioner: press the middle of the belt with your thumb—the deflection should be about 10–15 mm; or set it according to the torque value specified in the vehicle manual.

4. After rechecking the position to ensure accuracy, finally tighten the fixing bolts to the torque specified by the manufacturer (generally 25–35 N·m) to ensure no looseness.

3. Circuit Restoration & Inspection

• Reconnect the negative terminal of the battery, and check that all connections are tight with no exposed conductors.

• Use a multimeter to measure the voltage between B+ and GND. The voltage should be 27–29 V at idle speed and stably maintained at 26–28 V under load, confirming normal power generation.

Key Precautions for Installation of ISUZU 24V Generator

I. Precautions for Circuit Safety Operation

1. Power-off First PrincipleThe negative terminal of the 24V battery must be disconnected throughout the installation process. Live operation is strictly prohibited to prevent short circuits in the wiring harness that could burn the generator regulator or vehicle electrical components.
2. Wiring Specifications

• Wire strictly in accordance with terminal markings: The B+ (main output) terminal must be connected to a thick cable with a lock washer installed, and the torque should be controlled within 14–16 N·m. The D+ (excitation) terminal must not be reversed or left unconnected; otherwise, the generator will fail to build a magnetic field and generate no electricity.

• The cross-sectional area of the B+ cable shall not be less than 16 mm² to avoid heating due to high current. All wiring harness joints must be insulated to prevent short circuits caused by oil contamination or rain erosion.

3. Inspection Before Power RestorationAfter reconnecting the battery negative terminal, first use a multimeter to measure the static voltage between B+ and ground (it should be around the battery's rated 24V). Then start the engine to test the generated voltage, so as to avoid component damage caused by incorrect wiring.

II. Precautions for Mechanical Installation

1. Pre-treatment of Mounting SurfaceClean oil stains, rust, and impurities from the mounting surfaces of the generator bracket and shock absorbers. If the shock absorbers are aged or cracked, replace them immediately; otherwise, resonance noise will occur and bearings will be damaged.
2. Requirements for Bolt Fastening

• Install flat washers and spring washers on the fixing bolts. Pre-tighten first before final tightening; the final tightening torque shall comply with the vehicle manual (28–32 N·m for mainstream models). Over-tightening that could break the bolts is forbidden.

• Reserve adjustment allowance for the adjusting arm bolts and lock them only after the belt tension is properly adjusted to prevent position deviation.

3. Belt Tension Control

• Tension Standard: Press the middle of the belt with your thumb; the deflection should be controlled within 10–15 mm. Alternatively, calibrate with a dedicated tension meter to avoid errors from manual judgment.

• Hazards of Improper Tension: Excessively tight tension will accelerate wear on the generator bearings and water pump bearings, and shorten the belt service life. Excessively loose tension will cause belt slippage and speed loss, leading to insufficient power generation and high-temperature belt noise.

• When installing the belt, follow the original routing direction strictly; reverse winding is prohibited.

III. Precautions for Testing and Acceptance

1. Pre-start InspectionConfirm that all wiring connections are tight with no exposed conductors, the belt is free of distortion or misalignment, and there is no interference between the generator and surrounding components (such as the exhaust pipe and oil pipe).
2. Operational Test

• After starting the engine, listen for any abnormal noise from the generator at idle speed (such as bearing noise or belt slippage noise). If any abnormality is detected, stop the engine immediately for troubleshooting.

• Use a multimeter to measure the generated voltage at idle speed: 27–29 V is normal. When high-power electrical appliances (such as air conditioners and lights) are turned on, the voltage should be stably maintained at 26–28 V. If the voltage fluctuation exceeds 1 V, inspect for faults.

3. Long-term ProtectionApply anti-rust agent to the bolt threads and wiring terminals after installation. Especially under humid and dusty working conditions, regularly check the terminal insulation and belt condition.

IV. Precautions for Compatibility and Compliance

1. The generator model must match the ISUZU engine model (e.g., dedicated generators for 4HK1/6HK1 models). Mixing generators with different voltages or power ratings is forbidden to avoid incompatibility of the charging system.

2. Unauthorized modification of the excitation circuit or removal of the voltage regulator is strictly prohibited; otherwise, the battery will be overcharged and bulge, and vehicle electrical components will be burned.

3. The installation work must comply with maintenance safety specifications. Do not touch high-temperature components (such as the generator housing and exhaust pipe) when the engine is not cooled down to prevent scalding.

References：

I. Core Authoritative Sources

1. ISUZU Official Service Manual

   It covers core parameters such as the tightening torque of generator mounting bolts, definitions of wiring terminals (e.g., B+, D+), belt tension standards, and generator-engine compatibility requirements, serving as the fundamental basis for the content.
2. ISUZU Engine Model-specific Documentation

   It specifies generator installation standards for mainstream models such as 4HK1 and 6HK1, including details like mounting surface treatment for brackets, replacement criteria for shock absorbers, and circuit wiring procedures.
3. Universal Automotive Maintenance Industry Standards

   These include safety specifications for 24V generator circuit wiring, belt tension detection methods, and requirements for bolt anti-loosening and insulation protection, all of which comply with the general operational guidelines of the automotive maintenance industry.

II. Supplementary Reference Sources

1. Content from Industry Maintenance Platforms

   General generator installation procedures from platforms such as Autohome and PCauto are referenced to verify the universality of the operational logic.
2. General Technical Documentation for Generators

   It covers inspection points for components such as carbon brushes and rectifiers, as well as voltage testing standards (e.g., 27–29V at idle speed), with reference to the universal technical specifications for automotive generators.

III. Notes