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HomeTips & GuidesHow to Run Fuel Pump Direct to Battery: Connecting Fuel Pump to Battery

How to Run Fuel Pump Direct to Battery: Connecting Fuel Pump to Battery

How to run fuel pump direct to battery

Connecting the fuel pump directly to the battery without involving the relay may sound bizarre. But it works well in some scenarios, especially when you have a fuel pump pressure issue.

So the underlying question is, when should you make a direct connection? Also, are there some downsides to bypassing the relay, especially in the long run? 

Join us as we take you on a journey of improving your car’s fuel efficiency through this proven method.   

Why Do You Need to Run Fuel Pump Directly To Battery

A qualified mechanic with a car's fuel pump. 

A qualified mechanic with a car’s fuel pump. 

Wiring your pump directly to the battery is a quick-fix solution to boosting the gasoline flow. 

What are some of the conditions that may compel you to do so? 

Increased Pressure

The cardinal aim of this setup is to improve the fuel pressure. 

In turn, this improves the car’s performance while, at the same time, ensuring excellent fuel economy/efficiency. 

More Consistent Flow

Fluctuations in the fuel flow can also hamper performance. Directly connecting the pump is key in curtailing this problem as it ensures fuel runs constantly. 

Overall this enhances the overall performance of the vehicle, and it guarantees engine reliability.

Better Lighting

You can also make a direct connection to your car lights. It’ll have similar outstanding results as with the fuel pump. 

Doing so increases the power flow to the electrical systems, which is critical in those that require a power boost. 

Hence, a direct connection will significantly solve the problem of dimming and flickering lights. 

Prevent Corrosion

You’ve probably had corroded terminals if you’re in a high-humidity area. And you can solve the issue by having a direct battery connection. 

It’ll help prevent fuel pump terminal corrosion, which is common in such zones. 

Car Fuel Pump Wiring. 

Car Fuel Pump Wiring. 

Improve Performance

Overall, the car’s performance significantly improves when you avoid wiring issues. One way to achieve this is bypassing the relay if it’s the primary issue. 

Save Money

If your relay is damaged, you wouldn’t have to worry about fixing it if you have the direct connection option. 

Nonetheless, as earlier asserted, this is a short-term fix. Hence, a direct connection gives you room to repair the relay without pressure. 

How to Run a Fuel Pump Directly to a Battery

Note that this exercise may have slight variations in the parts and process depending on the car type. 

So we’re providing you with a generic formula to make the direct connection. 

Parts You Need

A disassembled car fuel tank. 

A disassembled car fuel tank. 

  • A Jumper wire
  • Fuel Pump
  • Car Battery
  • Fuse Holder
  • Soldering Iron
  • Electrical Tape
  • Safety Goggles 
  • A pair of pliers
  • Solder
  • A 30-amp fuse
  • Clamp 
  • Wire Cutter

Below is the connecting procedure: 

Attach a Fuse to the Battery

Electrical fuses. 

Start by attaching a fuse box to the battery. This process is significant in shielding the battery from potential damage.

 For this exercise, you’ll need to use your wire cutter to cut a small wire and connect it to the battery’s positive terminal. 

Next, connect the fuse holder to the other terminal using the soldering iron. 

An engineer with a car battery

An engineer with a car battery

Next, you must link the fuel pump relay to the battery. This component is critical in feeding current to the fuel pump. 

So the hard task here is finding where your relay is located. Your car’s user manual will come in handy in finding it. 

Next, using the wire cutter/pliers, cut a long cable. Its length should be sufficient to run from the fuel relay to the battery terminals. 

Attach this cable and ensure to insulate the points of connection to prevent power loss and possible electrical shorts. 

Connect the Ground Wire

The ground connection is highly critical. It’s the last piece of connector that completes the circuit, so you need to install it correctly.

 Locate a metal part in your car. It should be within the vicinity of the fuel pump. 

Next, link this point with your relay via a jumper wire. 

Connect the Trigger Wire

Using the wire cutter, slice the fuel pump wires to prepare a way to connect the trigger wire. 

When you switch on the car, the trigger wire links the fuel pump and the battery. 

Usually, the fuel pump wires are in a wire harness. So, split it to expose the two wires; 

  • Power Wire
  • Trigger Wire

You can tell the trigger wire from its white and black color. Connect the trigger wire terminal to the relay. 

Connect the Power Wire

Now, connect the power wire and one of its ends to the relay and the other to the fuel pump. 

It will be responsible for powering the fuel pump as the engine runs. 

Connect the Fuse and Test

Testing connections. 

Testing connections. 

You are almost done with your connections. But the remaining part is inserting the fuse in its port and testing. 

So please put it in its terminals then start the car. Allow it to be in idling mode, then check if the modification has worked. 

Confirm if your settings have improved the fuel pressure. If you did everything right, then it should work perfectly. 

If there’s no improvement, measure the voltage across the terminals using a multimeter. 

It will help you know if there’s been a significant improvement in the fuel pump current.

 If nothing works, engage a professional mechanic to help you out. 

Considerations to Keep in Mind When Rewiring

A thick wire gauge. 

A thick wire gauge. 

  • First, you must use a heavy gauge wire in your connections. It will help curtail potential power drops synonymous with thin gauge connectors. 
  • Also, a wiring harness will come in handy as you make the connections safe. An exposed wire will likely lose power or even experience a short circuit. Hence after making all the connections, use a wiring harness. 
  • Before embarking on a long journey, test your connections after making the modifications. Because if you make a wiring error, you’ll have difficulty finding the problem when your car breaks down. 
  • Finally, most importantly, confirm if there’s an improvement in the fuel pressure. Ensure it’s not too high, which can harm the engine’s functionality. 

Tips On How To Make Fuel Pumps Last Longer

Car Servicing. 

Car Servicing. 

  • Always ensure that you refuel before depleting what’s in the fuel tank. Allowing it to run low until the engine wipes up everything will strain the fuel pump. 
  • Also, when replacing your fuel pump, avoid low-quality models, which may be pricey in the long term. 
  • Similarly, use high-quality wires and make sure you have the most ideal gauges for your application. 
  • Don’t allow a fuel filter to run for more than a year. It will save you the higher cost of replacing the fuel pump. 
  • Again, refrain from fuelling from untrustworthy gas stations, as you may have debris-filled, low-quality gasoline. 
  • Clean and service your vehicle regularly. 


Fuel pressure is a cardinal determinant of the overall performance of your vehicle.

 And before you find time to take it to the mechanic, there’s a quick fix to help restore the pressure. 

Connecting the fuel pump directly to the battery works, albeit in the short term. 

It is also easy to execute, as highlighted in this article. Most importantly, involve a mechanic if you’re uncomfortable fixing the problem yourself. 

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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