Installation Procedure for Mitsubishi 12V Generator

I. Pre-installation Preparation (Safety and Pre-inspection)

Power-off and Protection Measures

1. Disconnect the negative cable of the battery and wait for 5 minutes for complete discharge to prevent electrical short circuits. Wear insulating gloves and safety goggles to avoid electric arcs caused by metal tools touching the terminals.

2. Clean the work area to ensure no oil contamination or flammable materials are present. Do not perform operations when the engine is hot.

Tool and Part Pre-inspection

Generator and Mounting Surface Cleaning

1. Check that the generator bearings are free from looseness and abnormal noise, the rectifier is not burnt, and the carbon brush length meets the standard. Clean the generator mounting surface and engine bracket to remove oil, rust and ensure a tight fit.

2. Verify the markings of the generator terminals (B+, IG, L, S, etc.) to ensure they match the vehicle wiring harness.

II. Installation Steps (Precision Operations)

Generator Positioning and Mounting

1. Place the generator gently on the engine bracket, align it with the mounting holes, and insert the fixing bolts (do not tighten them yet) to ensure the generator fits the bracket without skew.

2. For generators equipped with an adjustment arm, install the fixing bolts first, then install the adjustment arm bolts, leaving space for belt tension adjustment.

Electrical Connection (Core of Short-circuit Prevention)

1. First connect the generator’s B+ terminal (thick wire), install a lock washer, tighten it to a torque of 7–10N·m, and put on the insulating protective cap.

2. Connect the wiring harness connectors (IG/L/S, etc.) to ensure the latches are securely engaged with no looseness. Prevent the wiring harness from interfering with the belt and cooling fan.

Belt Installation and Tension Adjustment

1. Install the belt according to the OEM routing direction, fit it over the generator pulley, crankshaft pulley, water pump pulley and other pulleys, ensuring the belt is not twisted.

2. Adjust the generator position (via the adjustment arm or tension bolt) to achieve the standard belt tension: press the middle of the belt, the deflection should be 10–15mm (or follow the vehicle manual), and the reading of the tension gauge shall comply with OEM specifications.

3. Tighten the generator fixing bolts to 23–27N·m and the adjustment arm bolts to the OEM-specified torque. Recheck the belt tension to ensure no changes.

Re-inspection and Protection

1. Manually rotate the generator pulley to ensure there is no jamming or abnormal noise. Check that the wiring harness is free from extrusion and the mounting surface has no leakage.

2. Install the generator protective cover (if equipped) to prevent foreign objects from getting caught in the pulley.

III. Post-installation Commissioning and Acceptance

Static Testing

1. Reconnect the negative battery cable, turn on the ignition switch, and check if the charging indicator light illuminates. Start the engine—the indicator light should turn off, confirming the normal initialization of the power generation system.

2. Use a multimeter to measure the voltage at the B+ terminal: 13.8–14.7V at idle speed, and stably maintain 14.0–14.5V at medium to high speeds with no significant fluctuations.

Dynamic Testing

1. At idle speed, check that the generator operates without abnormal vibration or noise, and the belt shows no signs of slipping. Turn on electrical loads such as the air conditioner and headlights—the voltage should remain stable with no obvious drop.

2. Test-drive the vehicle for 5–10km, then recheck the belt tension and bolt torque to ensure no looseness.

Prohibited Operations

1. It is strictly forbidden to connect the generator without disconnecting the negative battery cable to prevent short circuits that could damage electronic components.

2. Never strike the generator housing or bearings with a hammer to avoid deformation and damage to internal components.

3. Do not set the belt tension too tight (which causes premature bearing failure) or too loose (which leads to slipping and insufficient power generation).

Precautions for Installation of Mitsubishi 12V Generator

I. Pre-installation Safety and Pre-inspection Precautions

1. Power-off Protection Specifications

1. Disconnect the negative cable of the battery before operation and wait for 5 minutes to allow complete discharge of the capacitors in the electrical system. It is strictly forbidden to plug or unplug the generator wiring harness with power on, to prevent arc burns or damage to the voltage regulator.

2. For vehicles equipped with an electronic control unit (ECU), additionally disconnect the ECU power connector to avoid triggering fault codes accidentally during installation.

3. Operators must wear insulating gloves and safety goggles, and use tools with insulated handles. Never touch the generator’s B+ terminal and housing simultaneously with metal tools to prevent short circuits.

References：

1. This source attribution covers core authoritative standards, OEM technical documents, parameter sources, and verification approaches to ensure all information is traceable and verifiable. All sources are publicly available authoritative technical documents (Standardization Administration of the People's Republic of China).

3. I. Core Authoritative Standards

5. National Standards

1. GB/T 18488.1-2015 Technical Specifications for Drive Motor Systems of Electric Vehicles - Part 1

   Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and the Standardization Administration of the People's Republic of China on February 4, 2015, and implemented on September 1, 2015 (currently replaced by GB/T 18488-2024). It specifies the basic safety, electrical performance, and precision requirements for motor system installation, serving as the compliance reference basis for generator installation (Standardization Administration of the People's Republic of China).

2. GB/T 5764-2011 Friction Facings for Automobile Clutches

   Clarifies the technical requirements, test methods, and inspection rules for friction components of automotive transmission systems, which is used for the reference judgment of generator belt friction performance and wear limits.

6. General Industry Specifications

1. General Specifications for Installation of Automotive Electrical Systems: Specifies basic operation procedures such as power-off protection, wiring harness connection, and insulation safety, applicable to the installation of automotive electrical components including the Mitsubishi 12V generator.

2. General Regulations for Bolt Tightening in the Automotive Maintenance Industry: Defines operation standards such as step-by-step diagonal tightening and torque control to ensure the generator remains free from looseness and skew after installation.

8. II. Brand-specific OEM Technical Sources

10. Mitsubishi Original Factory Maintenance Manuals

1. Core Operational Basis: Specialized maintenance manuals for various Mitsubishi models (e.g., the maintenance manual for 4G63 engine, Maintenance Manual PWEE9409-D for 4M40 engine) clearly specify key parameters such as generator fixing bolt torque (23–27N·m), wiring terminal torque (7–10N·m), belt tension standards, and specialized tool models.

2. Parts Matching Standards: Requirements for generator model compatibility (e.g., MD317200 is matched with 4G63 engine), carbon brush length standard (≥5mm), bearing condition inspection specifications, etc., are all derived from the charging system chapter of the manuals.

11. Mitsubishi Official Technical Support Documents

1. User Instructions for Specialized Tools for Generator Installation: Standardizes the usage requirements for tools such as torque wrenches and belt tension gauges, prohibits the use of substitute tools to avoid installation deviations.

2. Electrical System Safety Operation Specifications: Requires disconnecting the negative terminal of the battery and waiting for 5 minutes for discharge before installation to prevent electrical short circuits. This specification is derived from the general safety chapter of Mitsubishi's full-vehicle maintenance manuals.