ls swap external fuel pump kit

3 min read 04-02-2025

Swapping an LS engine into your vehicle is a popular upgrade, offering significant performance gains. However, a critical component often overlooked is the fuel system. The factory fuel pump in many donor cars may not be sufficient for the demands of a high-performance LS engine. This is where an LS swap external fuel pump kit comes in. This guide will walk you through everything you need to know about choosing and installing one.

Understanding the Need for an External Fuel Pump Kit

LS engines, especially modified ones, require a higher fuel volume and pressure than many original equipment (OE) fuel pumps can provide. Trying to run an LS on a low-pressure system can lead to lean conditions, poor performance, and even engine damage. An external fuel pump kit provides a dedicated, high-flow pump and all the necessary components for a reliable fuel delivery system.

Key Advantages of an External Fuel Pump Kit:

Increased Fuel Flow: Delivers the necessary fuel volume for high-performance applications.
Higher Fuel Pressure: Ensures consistent fuel delivery even under high demand.
Improved Reliability: A dedicated pump reduces strain on the OE system and improves longevity.
Easy Installation: Kits typically come with all the necessary components for a smoother installation process.
Flexibility: Allows for easy modifications and upgrades as your performance needs evolve.

Choosing the Right LS Swap External Fuel Pump Kit

Selecting the right kit depends on several factors:

1. Engine Specifications:

Engine size and modifications: A naturally aspirated 5.3L will have different fuel requirements than a supercharged 6.0L. Consider horsepower and torque outputs to determine the necessary flow rate.
Fuel type: Ensure the pump is compatible with your chosen fuel (e.g., gasoline, E85).

2. Fuel Pump Capacity:

GPH (Gallons Per Hour): This rating indicates the volume of fuel the pump can deliver. Higher GPH is generally better for higher-performance builds.
PSI (Pounds Per Square Inch): This rating specifies the pressure the pump can deliver. Consult your engine's specifications and fuel injectors' requirements for the appropriate pressure.

3. Kit Components:

Pump: The heart of the system, ensure it's from a reputable manufacturer known for reliability.
Wiring harness: A properly sized and insulated harness is crucial for safe and effective operation.
Filter: A quality fuel filter protects the pump from debris.
Mounting hardware: Ensure all necessary brackets and clamps are included for a secure installation.
Fuel lines and fittings: Use fuel-resistant lines and fittings rated for the pump's pressure.

Installation Considerations:

Installing an external fuel pump kit involves several steps. While the exact process varies depending on the kit, here's a general overview:

1. Planning and Preparation:

Consult your kit's instructions: Each kit has specific installation guidelines.
Gather necessary tools: Wrenches, pliers, wire strippers, etc.
Safety precautions: Always work in a well-ventilated area. Fuel is flammable.

2. Mounting the Pump:

Secure location: Choose a location that’s protected from damage and provides easy access for maintenance.
Proper mounting: Securely fasten the pump using the provided hardware.

3. Wiring the Pump:

Connect the wiring harness: Follow the kit's instructions carefully to avoid short circuits.
Relays and fuses: Use appropriate relays and fuses for protection.
Grounding: Ensure a proper ground connection for reliable operation.

4. Fuel Line Connections:

Connect the fuel lines: Use fuel-resistant clamps to ensure secure connections.
Bleed the system: Purge the air from the lines after installation to avoid cavitation.

5. Testing and Adjustment:

Test the system: Start the engine and check for leaks and proper fuel pressure.
Adjust pressure: If necessary, adjust the fuel pressure regulator to meet the engine's requirements.

Conclusion

An LS swap external fuel pump kit is an essential component for a successful and reliable LS engine swap. By carefully selecting a kit appropriate for your engine and performing a meticulous installation, you can ensure consistent fuel delivery and maximize your engine's performance. Remember to always prioritize safety and consult professional guidance if needed. This comprehensive guide serves as a starting point; always refer to your specific kit's instructions for detailed installation procedures and safety precautions.