Acura NSX 1990-2005 Electrical System Bolt Torque Specifications & Ground Points
Acura NSX 1990-2005

Acura NSX 1990-2005 Electrical System Bolt Torque Specifications

Comprehensive list of electrical bolt torque specifications for the 1990-2005 Acura NSX, covering various electrical components and connections.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

Always use a calibrated torque wrench and follow specifications exactly.

Incorrect Torque Sequence

Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

Clean and inspect all threads before assembly. Use new thread locker if specified.

Reusing TTY Bolts

Torque-to-yield bolts are designed to stretch and must not be reused.

Prevention:

Always replace TTY bolts with new ones. They are single-use only.

Dry vs. Lubricated

Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

Torque Wrench Care

  • Calibrate annually or after 5,000 clicks
  • Store at lowest setting
  • Keep clean and lubricated

Search Specifications

Search by component name, bolt size, or description

Torque Calculator

Convert between different torque units

Ignition System

Torque specifications for components of the ignition system.

1

Ignition Coil Mounting Bolt

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Ensure proper coil grounding. Do not over-tighten.

Starting System

Torque specifications for the starter motor and related components.

1

Starter Motor Mounting Bolts

M12 x 1.25
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Proper torque ensures secure mounting and good electrical ground. Ensure mating surfaces are clean.

Charging System

Torque specifications for the alternator and related components.

1

Alternator Mounting Bolts

M10 x 1.25
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Ensure proper alignment and ground connection. Do not over-tighten.

Battery System

Torque specifications for battery terminals.

1

Battery Terminal Nuts

M8 x 1.25
Torque Value
5 ft-lbs (7 N·m)
Important Notes
Avoid over-tightening which can damage terminals. Ensure terminals are clean and free from corrosion.

Electrical Grounding

Torque specifications for ground cable connections.

1

Ground Cable Mounting Bolts (Engine Block/Chassis)

M10 x 1.5
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Critical for reliable ground path. Ensure clean contact surfaces. Value is estimated.

Electrical Distribution

Torque specifications for fuse boxes, relay boxes and related components.

1

Fuse Box/Relay Box Mounting Bolts

M8 x 1.25
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Ensure secure mounting to prevent rattling. These often serve as ground points, so ensure clean mating surface. Value is estimated.

Engine Control

Torque specifications for ECU/PCM mounting.

1

ECU/PCM Mounting Bolts

M6 x 1.0
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Secure mounting for grounding. Do not over-tighten. Value is estimated.

Sensors

Torque specifications for various engine sensors.

1

Sensor Mounting Bolts (Crank, Cam, MAP, TPS, etc.)

M6 x 1.0
Torque Value
9 ft-lbs (12 N·m)
Important Notes
Ensures proper sensor ground. Estimated range. Do not over-tighten, as it can damage the sensor.

Wiring Harness

Torque specifications for wiring harness connectors.

1

Wiring Harness Connector Bolt

M4 x 0.7
Torque Value
3 ft-lbs (4 N·m)
Important Notes
Secure connector to prevent loosening and corrosion. Do not over-tighten. Value is estimated.

Lighting System

Torque specifications for headlight and tail light assemblies.

1

Headlight Mounting Bolts

M8 x 1.25
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Ensures correct alignment and ground connection. Value is estimated.
2

Tail Light Mounting Bolts

M8 x 1.25
Torque Value
7 ft-lbs (9.5 N·m)
Important Notes
Ensures correct alignment and ground connection. Value is estimated.
3

Interior/Exterior Lighting Fixture Screws

M4 x 0.7
Torque Value
3 ft-lbs (4 N·m)
Important Notes
Ensure good connection for electrical conductivity. Do not over-tighten. Value is estimated.

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

Common Issues

Bolt stretching, stripped threads, uneven torque patterns

Loose Components

Symptoms:
  • Rattling or vibration noises
  • Visible movement in components
  • Uneven panel gaps
Solutions:
  • Clean threads and mounting surfaces
  • Replace damaged fasteners
  • Apply proper torque in sequence
  • Use thread locker if specified

Stripped Fasteners

Symptoms:
  • Unable to achieve proper torque
  • Fastener spins freely
  • Visible thread damage
Solutions:
  • Use thread repair kit if appropriate
  • Install thread insert (HeliCoil)
  • Replace component if threaded hole is damaged
  • Upgrade to higher grade fastener if recommended

Overtightened Components

Symptoms:
  • Cracked or deformed parts
  • Broken fasteners
  • Compressed gaskets or seals
Solutions:
  • Replace damaged components
  • Use new fasteners
  • Follow proper torque sequence
  • Verify correct torque specifications

Diagnostic Steps

Visual inspection, torque verification, thread assessment

1

Visual Inspection

Inspect the affected area for any visible signs of damage or wear

  • Check for cracks or deformation
  • Look for signs of excessive wear
  • Verify proper fastener installation
2

Torque Verification

Verify the torque applied to the fasteners

  • Check the torque wrench calibration
  • Verify the torque specification
  • Compare the applied torque to the specification
3

Thread Assessment

Assess the condition of the threads

  • Check for signs of thread damage
  • Verify the thread type and size
  • Check for proper thread engagement

Prevention Guidelines

Best practices, maintenance tips, tool care

Best Practices

  • Always follow the recommended torque specification
  • Use the correct type and size of fasteners
  • Verify the torque wrench calibration regularly

Maintenance Tips

  • Regularly inspect the affected area for signs of wear or damage
  • Replace damaged or worn-out components promptly
  • Keep the work area clean and organized

Tool Care

  • Regularly clean and maintain the torque wrench
  • Store the torque wrench in a dry and secure location
  • Verify the torque wrench calibration before each use

Frequently Asked Questions

Find answers to common questions about torque specifications

Q1

Why are torque specifications important for electrical connections?

Correct torque ensures proper electrical contact, minimizing resistance and preventing overheating, which can lead to component failure or fire. Over-tightening can damage connectors or wires, while under-tightening results in loose connections and potential arcing.

Q2

What happens if I overtighten an electrical bolt?

Overtightening can deform connectors, strip threads, and damage wiring. This leads to unreliable connections, increased resistance, and possible electrical faults. In severe cases, it can cause wires to break or the connection housing to crack.

Q3

What happens if I undertighten an electrical bolt?

Undertightening an electrical bolt can lead to a high-resistance connection. This increased resistance generates heat, which can melt insulation and lead to intermittent electrical issues or fire hazards. A loose connection is also susceptible to vibration and can disconnect completely.

Q4

Can I use a general torque specification for all electrical bolts on my NSX?

No. Torque specifications vary depending on the bolt size, material, and the component it’s securing. Always refer to the specific torque specification in the NSX service manual for each connection. For example, the torque spec for a battery terminal connection will be different than the spec for an ECU ground.

Q5

Should I use anti-seize compound on electrical bolts?

Generally, anti-seize is NOT recommended for electrical connections. It can act as an insulator and increase resistance. Unless specifically stated in the service manual, keep electrical connections clean and dry.

Q6

What type of torque wrench is best for working on electrical connections?

A good quality, calibrated torque wrench is essential. For most electrical work on the NSX, a 1/4” or 3/8” drive wrench with an inch-pound or Newton-meter scale will be suitable due to lower torque requirements. A digital torque wrench is preferable for more precise applications.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

Temperature Effects

Includes: High Heat, Cold Weather, Thermal Cycling

Temperature can significantly impact torque values and fastener behavior

Cold Weather

Effects:
  • Increased material brittleness
  • Higher torque required due to thread contraction
  • Reduced thread lubricant effectiveness
Recommendations:
  • Allow components to warm to room temperature when possible
  • Consider using winter-grade thread lubricants
  • Check torque values more frequently during winter months

Hot Weather

Effects:
  • Thermal expansion of components
  • Decreased friction in threads
  • Accelerated lubricant breakdown
Recommendations:
  • Check torque when components are at normal operating temperature
  • Use temperature-resistant thread lockers
  • Consider re-torquing after heat cycles

Humidity and Corrosion

Covers: Rust Prevention, Salt Exposure, Moisture Control

Moisture and corrosion can affect fastener integrity and torque values

High Humidity

Effects:
  • Accelerated corrosion formation
  • Reduced friction coefficient
  • Potential thread seizing
Prevention:
  • Use corrosion-resistant fasteners
  • Apply appropriate anti-seize compounds
  • Maintain proper protective coatings

Salt Exposure

Effects:
  • Rapid corrosion development
  • Thread damage
  • Seized fasteners
Prevention:
  • Regular underbody washing
  • Use of sacrificial anodes where appropriate
  • Application of protective coatings

Seasonal Maintenance

Spring, Summer, Fall, and Winter maintenance schedules

Spring

  • Inspect for winter damage
  • Clean and protect exposed fasteners
  • Check torque on critical components

Summer

  • Monitor heat-affected components
  • Check expansion-related loosening
  • Inspect cooling system mounts

Fall

  • Prepare for winter conditions
  • Apply corrosion protection
  • Verify all fasteners are properly torqued

Winter

  • More frequent inspection of critical fasteners
  • Check for salt damage
  • Monitor suspension component torque

Related Resources

Tools, service procedures, and technical bulletins

Recommended Tools

Torque Wrench (3/8" Drive)

A 3/8" drive torque wrench is essential for accurately tightening electrical connections to specified torque values. It allows for precise control over applied force, preventing damage to components and ensuring proper electrical conductivity.

  • Click-type mechanism for audible and tactile feedback
  • Wide torque range suitable for various electrical connections (e.g., 5-25 ft-lbs)
Learn more

Torque Wrench (1/4" Drive)

A 1/4" drive torque wrench is necessary for smaller and more delicate electrical connections where lower torque values are required. It offers greater precision and is well-suited for sensitive components.

  • Click-type mechanism for accurate torque application
  • Low torque range suitable for smaller fasteners (e.g., 1-10 ft-lbs or inch-lbs)
Learn more

Socket Set (3/8" and 1/4" Drive)

A comprehensive socket set is needed to access various electrical connections, ensuring a proper fit on fasteners. Both 3/8" and 1/4" drive sizes are essential for different applications.

  • Variety of SAE and Metric socket sizes
  • Shallow and deep sockets for accessibility in confined spaces
Learn more

Extension Bars (3/8" and 1/4" Drive)

Extension bars are essential for reaching electrical connections that are located in tight or hard-to-reach areas. They provide added length and flexibility to socket wrenches.

  • Various lengths for different applications
  • Durable construction for reliable torque transfer
Learn more
Service Procedures

Battery Terminal Torque Procedure

This procedure outlines the steps for properly tightening the battery terminals on a 1990-2005 Acura NSX, ensuring optimal electrical connection and preventing corrosion or damage.

  • Disconnect the negative battery terminal.
  • Inspect terminals and clean any corrosion.
  • Position the terminal connector on the battery post.
  • Using the appropriate size socket, tighten the bolt to the specified torque value (typically 5-8 ft-lbs).
  • Reconnect the negative battery terminal.
  • Verify all connections are secure.
View full procedure

Ground Connection Torque Procedure

This procedure specifies the steps for properly tightening the various chassis and engine ground connections, ensuring proper grounding for electrical components.

  • Locate the specific ground connection.
  • Inspect connection surfaces and clean if necessary.
  • Position the ground terminal on the chassis or engine point.
  • Using the appropriate size socket, tighten the bolt to the specified torque value (typically 10-14 ft-lbs).
  • Verify connection is secure.
View full procedure

Sensor/Relay Connector Torque Procedure

This procedure details tightening various sensor and relay connector bolts, ensuring correct connection without damage.

  • Locate the connector and identify the bolt.
  • Position the connector and bolt.
  • Using the appropriate size socket, tighten the bolt to the specified torque value (typically 6-10 ft-lbs, check repair manual for each sensor).
  • Verify connection is secure.
View full procedure
Technical Service Bulletins

Corrosion Issues on Battery Terminals

1999-07-15

This bulletin addresses common corrosion issues found on the battery terminals in the 1990-2005 Acura NSX due to exposure to the elements.

1990-2005

Resolution: Clean battery terminals regularly and apply an anti-corrosion spray. Ensure proper torque on terminal bolts is maintained during reconnect to ensure optimal conductivity and prevent further issues.

Grounding Point Degradation on Engine Block

2002-03-20

This bulletin highlights the degradation of engine block grounding points which can cause intermittent electrical problems in the 1990-2005 NSX.

1990-2005

Resolution: Inspect engine block ground points regularly for corrosion or damage. Clean all grounding points thoroughly with a wire brush. Check grounding bolts and ensure they are tightened to the specified torque. Replace any damaged components.

About the Author

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Alan Montanye - Automotive Technical Specialist
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Alan Montanye

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