W-BODYTECH • ENGINE TECHNICAL LIBRARY

Ignition & Tune-Up

Spark plugs, plug gaps, wire sets, coil packs, firing orders and practical ignition-system service information for GM W-Body engines.

GM W-Body ignition coil packs
IGNITION BASELINE

Start with the exact engine and a known-good ignition system.

W-Body vehicles span multiple engine families, ignition layouts and service parts. Match the engine before selecting plugs, wires or coils, then verify the firing order and connections before startup.

Identify the engineModel year, VIN and engine family
Verify plug gapUse the applicable specification below
Route wires correctlyConfirm the firing-order diagram
Inspect connectionsCoils, module, boots and harness
IGNITION SERVICE

Tune-Up Procedure

Basic ignition maintenance covering plug and wire removal, inspection, coil service and reassembly.

TOOLS NEEDED

Before You Start

Preparation

  1. Ensure the engine is cool before starting.
  2. Disconnect the negative battery terminal to prevent any electrical shorts.

Removing Old Wires & Spark Plugs

  1. Locate the spark plugs. They are usually found on the top or side of the engine depending on OHV or DOHC engine.
  2. Label and remove all plug wires from the coils. Firing order can be found below for the 3800 and the 60° V6.

Inspecting and Gapping New Spark Plugs

  1. Check the gap on the new spark plugs using a spark plug gap tool. Adjust the gap according to your vehicle’s specifications.
  2. Apply a small amount of dielectric grease to the threads of the new spark plugs.

Installing New Spark Plugs

  1. Carefully thread the new spark plugs into the engine by hand to avoid cross-threading.
  2. Use the torque wrench to tighten the spark plugs to the manufacturer’s recommended torque specification.

Replacing Ignition Coils

  1. Using the 5.5mm socket, remove both screws from each coil pack.
  2. Using the 7mm socket, unscrew the connector from the bottom of the module. 60° V6 engines just have three plugs.

Prepping and Cleaning the Coils and Module

  1. Using the electronic cleaner, spray the top and bottom of the coils where they connect to the wire and tabs, then clean using the copper brush.
  2. Using the electronic cleaner again, clean the connections on the module at the point where the coils connect and the connector(s) itself.
  3. Using the electronic cleaner one last time, clean the connector(s) from the engine harness.
  4. Let dry.
  5. Once everything is dry, apply the Di-Electric Grease to all connections, coil top and bottom, module connector(s), and plug boots.
  6. Install the new coils in the reverse order, ensuring all connections are secure.

Reconnecting the Battery

  1. Reconnect the negative battery terminal.
  2. Start the engine to ensure everything is functioning correctly.

Tips for Optimal Performance

  • Regularly check and replace spark plugs and ignition coils as part of your vehicle’s maintenance schedule.
  • Use high-quality replacement parts to ensure longevity and performance.
  • Keep the ignition system clean and free of debris to prevent misfires and other issues.
REFERENCE

Firing Orders

Use the diagram that matches the engine family before reconnecting plug wires.

2.8, 3.1 & 3.4

2.8, 3.1 and 3.4 V6 firing order

3100 & 3400

3100 and 3400 V6 firing order

3800

3800 V6 firing order
IGNITION SPECIFICATIONS

Spark Plugs

Plug references and gaps from the existing W-BodyTech ignition guide, organized by engine family.

2.8 V6 & 3.1 V6

  • ACDelco CopperR44LTSM
  • Autolite Copper5245
  • Plug Gap0.45

3.1 Turbo VIN V

  • ACDelco CopperR42LTS
  • Autolite Copper103
  • Plug Gap0.45

3.4 DOHC V6

  • ACDelco Iridium41-993
  • Autolite XP IridiumXP5243
  • Autolite Copper5243
  • Plug Gap0.45

3100 & 3400 V6

  • ACDelco Double Plat41-940
  • Autolite Copper606
  • Plug Gap0.60

3.6 DOHC V6

  • ACDelco Iridium41-109
  • Autolite XP IridiumXP5263
  • Autolite PlatinumAP5263
  • Plug Gap0.45

3800 N/A

  • ACDelco Double Plat41-902
  • Autolite PlatinumAP606
  • Autolite Copper606
  • Plug Gap0.60

3800 SC

  • ACDelco Double Plat41-902
  • Autolite PlatinumAP606
  • Autolite Copper606
  • Colder Autolite Copper104 & 103
  • Plug Gap0.60
Colder 104 & 103 plugs require a tune.
REPLACEMENT REFERENCE

Wire Sets & Boots

Existing W-BodyTech wire-set and ignition-boot references grouped by engine.

2.8 & 3.1 V6

  • Delphi WiresetXS10206
  • ACDelco Wireset9706R
  • Duralast Gold WiresetD801163

3.4 DOHC V6

  • Duralast Gold Wireset4877

3100 & 3400 V6

  • Delphi WiresetXS10226
  • NGK Wireset51107
  • Duralast Gold WiresetD801096

3.6 DOHC V6

  • NGK Boots58984
  • Duralast Gold Boots90098

3800 V6

  • ACDelco Wireset9746BB
  • NGK Wireset51031
  • Duralast Gold WiresetD801110
COIL REFERENCE

Coil Pack Readings

Low-voltage and high-voltage readings retained from the existing W-BodyTech ignition page.

Std Emotec Coil Packs

Gray Bottom
Low Voltage Side • Bottom
0.90.90.90.90.90.80.90.90.9
High Voltage Side • Top
580056805750580058005700581058005700

L67 Coil Packs

Blue Bottom
Low Voltage Side • Bottom
0.80.90.90.90.90.90.80.90.9
High Voltage Side • Top
564057305750580058005750580058005750

MSD Coil Packs

Gray Bottom
Low Voltage Side • Bottom
0.80.80.8
High Voltage Side • Top
566056405790
W-BODYTECH COMMUNITY

The Garage Never Closes.

Use the website for organized technical reference and the W-BodyTech community when you need help with a specific engine, ignition problem or parts combination.

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