How To Run Fuel Pump Direct To Battery – [In 5 Steps!]

Have you been wondering what can spice up an excellent long-distance driving time? Is it the function of the engine, or is it how the battery is connected?

Any upgrades can make things look better, but you can do a few tricks as well!

Here, you may want to know how to run the fuel pump directly to the battery.

The process required for this is connecting the battery to the fuse and fuel relay and then grounding the connections. After that, you will be connecting the pin to the relay and route the wiring connections. At the end of it, you have to ensure that you are avoiding any unstable voltage issues

So, are you up for the run? Don’t go away, see what more you can know!

Why Do You Need to Run Fuel Pump Directly To Battery

By running the fuel pump directly to the battery, you can enjoy a few benefits. This is if the wiring connections are compatible and secure enough.

How do you figure out the availability then?


Source: Shomespeed

See, how the fuel pump is placed, it is customized with the wiring configuration that is connecting to the battery. There are often chances of batteries misfiring due to a complex configurated mechanism. 

By wiring a direct system, you will be removing a few obstacles, let us explore the reasons!

Comparison FactorsDirect Wired Fuel PumpRegular Wired Fuel Pump
Operational EfficiencyBetterNot Good Enough
Overheating And DamagePrevention PossibleEasily Overheats The System
Cost SavingsYesNo
ReliabilityMore Less

Reason 1: Operational Efficiency

A complete rewiring will improve operational performance. The signals will be direct without impacting the other parts that lose their functions sooner. 

The fuel pump will be benefited from no short-circuiting issues with a direct wiring system. There is no capacity for any part to intrude and play with the durability context of the pump placement. 

Reason 2: Prevent Overeating And Damage

As mentioned before, there are always areas for the engine and batteries to overheat easily. This is due to many external and internal reasons, mostly associated with the wires that are rusting fast. 

With a direct connection, it is possible to prevent some damages that can come about with the parts. 

Reason 3: Saving Cost

Frequent issues surfacing with the wires, cables, and different parts mean spending money on repairs. You are saving a lot of costs when the connection is directed.

As the battery and fuel pump is working with no barriers, the system will be more efficient. This means the parts do not default quickly and so you will be saving on those maintenance costs. 

Reason 4: Reliability

A direct connection releases a lot of havoc. It makes the parts more reliable due to better operational efficiency. This means the battery and the fuel pump are going to be more durable. 

A non-direct electric configuration of the fuel pump is associated with a few dangers. They reach lower levels of safety standards on most occasions. 

How To Run Car Fuel Pump Direct To Battery?

It is not a difficult process, especially if you understand how the system is wired. A clear picture will make things work for you when the right steps are applied.

Apart from this, do seek expert hands in case you are not comfortable doing the job yourself. See what a visit to the service center reveals.

You will be working on it depending on how you are professionally advised to do so!

Checklist Before Directing Fuel Pump To Battery

Few conditions should meet the needs when you are working on the rewiring scenario. Before heading into the checklist, do confirm if the battery functions are reducing the engine power

A good rewiring possibly can solve this issue from appearing. Keeping the logical allocations under concern, here is what you need to ensure:

  • Check if the battery voltage is compatible with the fuel pump
  • Understand if the wiring outlet is supportive enough for the grounding 
  • The power distribution should be sufficient and effective. You may have the option of introducing heavier gauge wire for better output.

If these requirements are met, there shouldn’t be any drawbacks to the rewiring process. 

5 Steps To Run Car Fuel Pump Direct To Battery

In the initial stages, the work is mostly done involving the relay. You need to uncover a direct route from the fuel pump cable set up and to the battery. 

As the battery terminals are connected to the control box, the direction will mostly go there. 

Check out how taking a few steps separately, will make things work in the right way. 

Step 1: Battery Connecting To The Fuse And Fuel Relay

The first thing you need to do is work with the positive terminal of the battery. The wires must be cut or trimmed to the perfect measurement. This is to allow the cables appearing from the relay to connect properly. 

Here comes the attribute of the fuse holder. The fuse must be placed adequately with the soldered fuse holder. 

The wire from the holder will go directly to the bottom end of the battery terminal. This should be clipped precisely the way it is directed in the manuals. 

After that, you will need another cable, soldered or cut to the right measurement. The cable will be connecting the fuel relay. 

The hard work involving the initial step is done, let’s move on to the next… 

Step 2: Grounding

Grounding is an essential part of the process, it simply means connecting the wires and cables together. One end of the relay cable will hit the positive terminal of the battery. The other end would connect through the screwed system of the fuel pump. 

See, how it is working here- 


Source: Vasttuning

The right wire that is coming out of the pump should be cut a few inches. This is when it appears out of the tank to connect the relay. The left wire is grounding itself to the electronic system. 

As stated before, the relay will take out the cable to connect one end of the battery. 

Step 3: Connecting Pin To The Relay

So, what have we learned with the grounding process, where is the line going? Let’s look further – 

Relay diagram

Source: AAMP Global 

The grounding mechanism is appearing directly to the battery-positive terminal. It is amplifying the fuse. We do have to make sure there is the right voltage capacity present. This should be a 12v power relay connection. 

The pin connection to the relay will make the overall electrical system function. This means the whole mechanism is directing all the parts to perform their functions. 

Here, you will be noticing how the fuel pump has taken up the stage for a direct connection to the battery. 

Step 4: Routing The Wiring Connections

A good routing process will make the complex mechanism look much simple. We will be getting rid of the clusters that are happening with all those wires. 

First, look at how the battery terminals are appearing with the fuse. The fuse is going to bypass the system with a simplified wiring spread from the fuel pump.

The relay will be connecting the switches to allow a proper flow of electronic distribution. This is when the vehicle is in operation. 

All the soldered parts must fit in sufficiently to let the electric system work. 

As the new configuration is administered, a turned-on engine will let the system run smoothly. 

Step 5: Avoiding Unstable Voltage Issues

Don’t run into the driving seat to start the engine right away. There is a little more thing to do concerning how the newly connected battery is working. 

There shouldn’t be any problems if the combability is there with the fuel pump. We have stated this before! Also, if the battery is working at its best, you wouldn’t be worried about unstable voltage issues. 

Remember, if you have rewired the system, you have to check if there are any errors made by you. A few conditions with the parts may drain the battery to block engine performance

Do ensure the fuses and the ignition switches have not defaulted. Use a voltmeter to understand if there is any fluctuation in voltage is happening. 

When everything seems right, you are ready to start the engine!

Safety and Precautionary Measures

Your safety can be guaranteed 100% when you are confident about your work. Working alongside professionals will make things easier. This is with zero possibility of bad things happening. 

Make sure to put on protective gear, involving goggles and gloves.

Other than that, your work should encounter a few important factors. This is mostly related to the prevention of any negative outcomes, such as a fire eruption. 

Here are they:

  • Ensure that the pump is not stressed when the rewiring is done
  • Also recognize that the right fuel pump is used which is designed specifically for the direct wiring function
  • Follow professional directions provided by mechanics in terms of battery storage and charging. Do not let these things rest in a high-heat area. 

All the matters will solve themselves naturally and your work output will reflect satisfactory results. 

Tips On How To Make Fuel Pumps Last Longer

There are a lot of things you can do so that the fuel pump doesn’t die down sooner. In contrast, to improve the lifespan, some good implications will assist the matter.

  • Always keep the tank full, don’t wait for the fuel gauge to read zero for the refueling
  • Make sure you have installed a high-quality fuel pump from the best manufacturer out there
  • Also, ensure that the wiring is done with high-quality materials that are durable
  • Replace fuel filters every year
  • Keep the pump away from dirt and debris
  • Clean regularly and the take the vehicle to the service center more often

As much as you love your car, you can be enjoying the maintenance scenario. It will just promote a longer lifespan for not only the parts but your car as well. 

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Can you bypass a fuel pump relay?

Yes, it is possible to do the bypassing where the relay bypass switch will be plugged. This is to provide the fuel pump relay to have direct control over the circuit connecting the fuel pump. 

What voltage should a fuel pump have?

Most lithium car batteries are of 12 voltage. For direct running, the compatibility of the fuel pump has to be around 12 voltage also. It may not hurt if the voltage goes around 12.5 to 13 volts. 

Why does a fuel pump need a relay?

The fuel pump needs a relay for the engine to run efficiently. The combustion engine model will not run without a relay as the fuel distribution won’t happen. It is the job of the fuel pump relay to ensure that the engine gets what it requires. 


It is evident that the right facts are provided for you to know how to run the fuel pump directly to the battery. Few directions may have taken a deeper and in-detail path, but it is for your own good.

We wish you all the best with your projects, it is time to leave… 


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