Replacing Fuel Pumps In Vehicles With Dual Tanks

Changing the fuel pump in a vehicle with dual tanks can be a complex task, and there are a few things to consider. Firstly, it is important to determine if the vehicle has a shared fuel level gauge, as this will impact the process. Additionally, when upgrading to an electric fuel pump, you may need to change the fuel lines to accommodate the new pump and mount it after the dual tank switch. It is also recommended to install a fuel pressure regulator to maintain the appropriate fuel pressure for the engine. Furthermore, when plumbing the dual tanks, it is essential to consider the location of the tanks and the method of fuel draw. Some vehicles may require a transfer pump to move fuel between the tanks, while others may use a gravity feed system.

Electric fuel pump for dual tanks

Overview

If you have a dual-tank vehicle and want to install an electric fuel pump, you may be wondering if it's possible and what modifications are needed. The good news is that it can be done, and you have a few options to choose from. This guide will take you through the process step by step, offering detailed instructions and helpful tips from other dual-tank vehicle owners who have successfully made the switch.

Step 1: Compatibility

First, you need to determine if your electric fuel pump is compatible with your dual-tank setup. In most cases, it should be possible to use an electric fuel pump with a standard dual-tank system, but you may need to make some changes.

Step 2: Fuel Lines

You may need to change the fuel lines to accommodate the electric pump. This involves mounting the electric pump after the dual-tank switch and ensuring the lines are properly connected.

Step 3: Mounting the Pump

The electric fuel pump should be mounted between the dual-tank switch and the engine. This location ensures the pump can draw fuel from either tank and supply it to the engine.

Step 4: Fuel Pressure Regulator

It is recommended to install a fuel pressure regulator, especially if you are switching to a carbureted setup. This will help reduce the fuel pressure to the appropriate level for the carburetor.

Step 5: Additional Considerations

If you have a mechanical fuel pump in place, it is essential to remove it before installing the electric pump. Keeping the mechanical pump can lead to fuel ending up in the crankcase if the diaphragm fails, causing significant issues.

Additionally, consider the benefits of having two electric fuel pumps. While it is more expensive and challenging to install, having a backup pump can be useful if one fails, and it can reduce strain and noise if your tanks are far from the pump.

Step 6: Dual Tank Fuel Pump Kit

If you're looking for an all-in-one solution, consider purchasing a dual-tank fuel pump kit. These kits include everything you need for the installation, such as fuel pumps, filters, mounting hardware, and detailed instructions.

Installing an electric fuel pump on a dual-tank vehicle is a feasible project, but it requires careful planning and execution. By following the steps outlined above and seeking advice from other enthusiasts, you can successfully upgrade your fuel system for improved performance and reliability.

Fuel pressure regulator

A fuel pressure regulator is an important component of a dual-tank fuel system. When upgrading vehicles with two fuel tanks to EFI, a challenge arises: not only must a fuel source be selected, but the return-style fuel regulator must return the fuel to the same tank. This is where a fuel pressure regulator comes in.

A fuel pressure regulator ensures that the fuel pressure is maintained at the correct level for the engine. It does this by allowing excess fuel to return to the tank, thereby reducing the pressure. This is crucial for the engine's performance and fuel efficiency.

When choosing a fuel pressure regulator, it is important to consider the specific requirements of your vehicle. For example, if you have a carbureted vehicle switching to an EFI system, you will need a regulator that includes pressure regulation. It is also important to consider the fuel tank setup. If your fuel tanks are located close together, a single pump with a fuel pressure regulator may be adequate. However, if your tanks are located further apart, you may need to consider a dual-pump system to reduce strain on the pump and minimise noise.

Additionally, it is worth noting that some vehicles with dual fuel tanks use a dual-stage auto-changeover regulator. This type of regulator automatically switches from the empty tank to the full one, ensuring an uninterrupted fuel supply. This can be particularly useful for RVs, camping, and grilling, where a constant fuel supply is crucial.

Fuel lines

When changing the fuel pump on a vehicle with dual tanks, you may need to change the fuel lines to hook up to the electric pump. The fuel lines will need to be EFI-rated fuel hoses, with 3/8- and 5/16-inch EFI-rated hose clamps.

The fuel lines will need to be connected to the fuel pump, which should be mounted between the dual tank switch and the engine. The fuel pump will also need to be connected to the fuel tank return port, which returns the fuel to the same tank. This is done using a motorized valve for switching the fuel source, return, and sender.

If you are using a single fuel pump, it should be mounted close to both tanks, ideally within 18-24 inches (horizontally) from either tank. This will reduce strain on the pump and minimize the noise produced by the pump.

If you are using dual fuel tanks, you will need to consider how the tanks are plumbed together. One option is to use a Y-connector to join the supply lines from both tanks, as well as the return lines, and connect the vent lines between the two tanks. This will allow for equilibrium between the tanks, so the fuel level stays the same on both sides. However, it is important to note that you will need to add fuel to both tanks simultaneously when refueling, as the fuel will not equalize if you only fill one tank.

Another option for plumbing dual fuel tanks is to use a dual-circuit ball valve or a manual dual-port valve to switch between the two tanks. This will allow you to maintain separate fuel levels in each tank and avoid the need to fill up both tanks at the same time.

Mounting the pump

To mount the pump, you will need to decide on the location of the pump in relation to your dual tanks. The pump should be mounted after the dual tank switch and before the engine. The closer the pump is to the tanks, the better, as this will reduce strain on the pump and minimise the noise produced.

If your tanks are located very close together, you may only need one pump, which can be mounted near both tanks. If your tanks are further apart, you may need to consider installing two pumps, with one pump located near each tank. This will ensure that the fuel can be easily drawn from both tanks and will reduce the strain on a single pump.

When mounting the pump or pumps, follow the instructions provided with your fuel pump kit. For example, the EFI System Pro Dual Tank Fuel Pump Kit includes mounting brackets and clamps to secure the pump in place. You may also need to change the fuel lines to hook up to the pump, depending on your vehicle's setup.

It is important to note that the location of the pump can vary depending on the vehicle's make and model, as well as the specific fuel pump kit being used. Always refer to the manufacturer's instructions and consult a professional if you are unsure about the installation process.

Fuel tank return port

When upgrading vehicles with dual fuel tanks to an EFI system, a fuel return-style regulator is required to return the fuel to the same tank. If your tank does not have a return port, you will need to install one.

Bulkhead Fitting

This fitting requires a 9/16-inch hole for the fuel port. It uses a nut on the inside of the tank to secure the fuel port in place. It is recommended to use a step bit when drilling the hole. The installation can be made easier by drilling the hole in the sender "hat" and removing it from the tank to prevent debris from falling into the tank. The convoluted tube should be positioned near the pickup to prevent fuel starvation at low fuel levels. A 5/16-inch return line is usually adequate for fuel pumps that flow 255 LPH of fuel or less. If your fuel pump flows more, a 3/8-inch return port is required.

Weldless Fitting

This fitting requires a 1/2-inch hole for the fuel port. It does not require access to the inside of the tank, as it "balloons" the port inside the hole, allowing the port to self-secure. However, it is important to ensure that no shavings or debris are left inside the tank. This fitting can also be installed by drilling the hole in the sender "hat". The convoluted tube should be positioned near the pickup to prevent fuel starvation at low fuel levels. A 5/16-inch return line is usually adequate for fuel pumps that flow 255 LPH of fuel or less. If your fuel pump flows more, a 3/8-inch return line is required.

Return Line Kit

The Moroso 65385 EFI Fuel Return Line Kit is an example of a product that can be used to return fuel to the tank. It is made of stainless steel and aluminum and has a nominal wall thickness of 25.15 centimeters. It has received positive reviews for its ease of installation and functionality.

Frequently asked questions