ls header spark plug wires

Lemon

3 min read

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05-02-2025

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Routing spark plug wires correctly on your LS engine swap is crucial for performance and reliability. Improper routing can lead to misfires, poor engine performance, and even damage to your engine's components. This guide will walk you through the process, covering best practices and troubleshooting common issues.

Understanding the Importance of Proper Routing

LS engines, known for their power and efficiency, are popular choices for engine swaps. However, the intricate design necessitates meticulous attention to detail, especially when it comes to spark plug wire routing. Poorly routed wires can cause:

• Misfires: A poorly routed wire can pick up electromagnetic interference (EMI) from other components, causing misfires and inconsistent engine operation.
• Reduced Performance: Misfires directly impact horsepower and torque output.
• Engine Damage: Severe misfires can lead to damage to the catalytic converter, oxygen sensors, and even the engine itself.
• Difficult Diagnostics: Tracing the source of intermittent issues becomes significantly more complex with improperly routed wires.

Factors Affecting Wire Routing

Several factors influence how you route your LS spark plug wires:

• Header Type: The design of your headers (long tube, shorty, etc.) will dictate available space and the paths the wires must take. Long tube headers often present more challenges due to their proximity to the engine block and other components.
• Wire Length and Type: Using the correct length wires is essential. Too short, and they'll be under stress; too long, and they'll be prone to interference and damage. The type of wire (silicon, etc.) also plays a role in its flexibility and resistance to EMI.
• Engine Bay Components: The location of other components in your engine bay—like the alternator, power steering pump, and AC compressor—will influence your routing options.
• Grounding: Proper grounding of the engine and associated components is critical for minimizing EMI.

Step-by-Step Routing Guide

While specific routing will vary based on your setup, these general steps provide a solid foundation:

1. Identify Firing Order: Begin by confirming the correct firing order for your specific LS engine. This information is usually found in your engine's service manual.

2. Start with the Longest Wire: Typically, the longest wire connects to the furthest spark plug. This is often cylinder #7 or #8 depending on your engine configuration. Route this wire first, ensuring it's held securely but has enough slack to avoid excessive tension. Avoid sharp bends and keep the wire away from high-heat areas.

3. Route Subsequent Wires: Work your way through the remaining wires, following the firing order. Maintain consistent spacing between wires to prevent interference.

4. Secure the Wires: Use wire looms, clamps, or other appropriate fasteners to secure the wires and prevent them from moving around. Ensure the wires aren't pinched or touching hot surfaces.

5. Inspect for Interference: Once routed, carefully inspect the wires for any potential interference from other engine components. Adjust as needed to ensure clear spacing.

6. Test and Adjust: After installation, thoroughly test the engine to check for any misfires or performance issues. Adjust the routing if necessary.

Troubleshooting Common Issues

• Misfires: If you experience misfires after routing the wires, double-check the firing order, wire routing, and securement. Inspect the wires for any damage or signs of interference.
• Intermittent Issues: Intermittent misfires may indicate a grounding issue or EMI interference. Check your engine's ground points and consider using shielded spark plug wires.

Conclusion

Correctly routing LS header spark plug wires is a crucial aspect of any LS engine swap. By following these steps and paying close attention to detail, you can ensure optimal performance, reliability, and prevent potential engine damage. Remember to consult your engine's service manual for specific details and diagrams. If you're unsure about any aspect of the process, it's always best to seek the help of a qualified mechanic.