how to direct wire a fuel pump

How to Direct Wire a Fuel Pump?

Direct wiring a fuel pump to a battery can be a useful technique to ensure a continuous supply of fuel to your vehicle’s engine. By bypassing the fuel pump relay and connecting the pump directly to the battery, you can improve fuel economy, performance, and even prevent potential issues with the electrical system. In this article, we will guide you through the process of direct wiring a fuel pump, highlighting important considerations and benefits.

Understanding the Fuel Pump

Before diving into the direct wiring process, it’s important to understand the role of a fuel pump in your vehicle. A fuel pump is an electronic device responsible for regulating the flow of fuel from the tank to the engine carburetor. In modern cars, the fuel pump is usually located inside the fuel tank for better efficiency and safety.

Considerations Before Direct Wiring

Before proceeding with direct wiring, there are a few considerations to keep in mind. Firstly, ensure that the voltage of your battery is compatible with the fuel pump. Most batteries are 12-volt, so using a compatible pump is crucial if your battery has a different voltage. Additionally, make sure all connections are secure and use a heavier gauge wire suitable for automotive applications to provide sufficient power to the fuel pump.

Step-by-Step Guide to Direct Wire a Fuel Pump

Follow these steps to successfully direct wire a fuel pump to your battery:

  • If using two fuel pumps, turn off both pumps and connect them using hose clamps to ensure a tight connection.
  • Cut the ECU stock wire and wire the pin 85 of the relay to supply 12V power to energize the relay.
  • Connect pin 86 of the relay to the ground, ensuring a clean connection.
  • Use a dedicated wire to connect pin 30 of the relay to the battery, providing a direct power source.
  • Route a wire from the recent aspects of the fuel pump to pin 87 of the relay.
  • Install a fuse in the battery feed connection to protect the circuit.
  • Disconnect the fuel pump wiring carefully, ensuring proper handling.

Benefits of Rewiring the Fuel Pump

Rewiring the fuel pump offers several benefits that can enhance the performance and safety of your vehicle. Firstly, it helps prevent potential problems with the fuel pump, ensuring a smooth operation. It can also improve the overall performance of the pump, resulting in better fuel delivery and engine efficiency. Additionally, rewiring the fuel pump can prevent fire hazards, especially if there are damaged wires. Moreover, it can save you money in the long run by avoiding costly repairs or replacements of internal wiring components.


Direct wiring a fuel pump to a battery can provide numerous benefits, including improved fuel delivery, enhanced performance, and increased safety. By following the step-by-step guide and considering the necessary precautions, you can successfully direct wire your fuel pump and enjoy a reliable and efficient driving experience. Always prioritize safety and consult a professional if you encounter any difficulties or uncertainties during the process.


If the fuel pump is not installed correctly, you may experience issues such as engine performance limitations, unstable voltage, and a decrease in fuel flow. It’s essential to check for any signs of fuel pump malfunction, such as engine sputtering, difficulty starting, or a noticeable decrease in power.

The fuel pump relay typically receives power from the engine’s electrical system, usually sourced from the battery. It plays a crucial role in regulating and controlling the flow of electricity to the fuel pump, ensuring the pump receives the right amount of power while protecting it from overloading.

Removing the fuel pump relay will interrupt the power supply to the fuel pump, resulting in the pump not receiving any electricity. As a result, the engine will not receive the necessary fuel for combustion and will eventually stall.

While it is possible to run a fuel pump directly to a battery, it is generally not recommended. Fuel pumps are designed to work with the vehicle’s electrical system and running them directly from the battery can put undue stress on the pump, potentially shortening its lifespan.

Running a fuel pump directly from the battery can lead to potential risks, such as increased chances of fire hazards if the wiring is not correctly done. Moreover, certain fuel pumps may not be compatible with direct wiring, further increasing the risk of damage or malfunction. It is advisable to consult a professional mechanic or electrician before attempting to wire a fuel pump directly to a battery.

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