Fuel Tank To Fuel Cell: Easy, Safe Conversion Guide

Replacing a behind-seat fuel tank with a fuel cell is a complex process that requires careful consideration and planning. This process is often undertaken to free up space, improve ground clearance, or address safety concerns. It is important to note that there may be legal restrictions on relocating fuel tanks, especially if the new location is within the cabin area. When choosing a new fuel cell, it is essential to select one that fits the specific make and model of your vehicle, ensuring that it maximizes fuel capacity and utilizes external fuel pumps for added safety.

Check if the rear tank is usable

Before relocating your fuel tank to a rear seat-mounted fuel cell, it is important to check if your rear tank is usable. Here are some factors to consider:

Tank Material

The material of your tank will determine its durability and safety. Plastic tanks are a good option as they are less prone to cracking and leaking compared to aluminum tanks. However, some people prefer aluminum tanks for their strength and rigidity. If you choose an aluminum tank, ensure that it is TIG welded for ultimate strength.

Tank Capacity and Dimensions

Consider the capacity and dimensions of the tank to ensure it fits behind the rear seat. The Motobilt fuel tank, for example, has a capacity of 18 US gallons and is designed to fit behind the rear seat of a Jeep YJ. It is CNC cut and press brake formed to maximize space. Ensure that the tank you choose has the appropriate capacity for your vehicle's needs and fits securely behind the seat.

Mounting Options

There are different ways to mount a fuel cell, and the choice depends on your preference and vehicle setup. Some people choose to mount the tank using straps and rubber mounts, which allow for some flexibility and movement. Others opt for rigid mounting using the tabs or ears of the tank. Consider the pros and cons of each method and select the one that best suits your requirements.

Fuel Pump and Level Sender

The choice between an internal or external fuel pump is important. Internal fuel pumps can be more challenging to work with and may require an external fuel level sender for accurate readings. External fuel pumps, on the other hand, are generally easier to install and access but may require additional fittings and modifications. Consider the ease of installation, maintenance, and reliability when making your decision.

Fumes and Ventilation

When relocating the fuel tank inside the vehicle, it is crucial to consider fumes and ventilation. Ensure that the tank is properly vented to prevent fuel odors from building up inside the vehicle. Some people choose to vent the tank to the charcoal canister, while others drill a hole through the wheel well for external ventilation. Assess your vehicle's setup and choose a ventilation method that suits your needs.

In summary, when checking if your rear tank is usable for relocation, consider the tank material, capacity, dimensions, mounting options, fuel pump setup, and ventilation. Ensure that the tank is safe, securely mounted, and does not pose any risks to the driver or passengers.

Ensure the fuel selector switch is still next to the driver's seat

When replacing a behind-seat fuel tank with a fuel cell, it is important to consider the placement of the fuel selector switch to ensure it remains easily accessible to the driver. Here are some detailed instructions and considerations to ensure the fuel selector switch is still next to the driver's seat:

• Firstly, assess the location of the existing fuel selector switch. In some vehicles, the fuel selector switch may already be located on the dash near the driver's seat, which simplifies the process.
• If your vehicle has a dash-mounted fuel selector switch, you may need to purchase a new electric fuel valve to replace the stock valve located under the driver's seat. This will involve understanding the wiring configuration of the switch. Typically, the switch should be a double pole, single throw switch, with the upper set of connections creating a ground circuit for the fuel senders/floats in the tank.
• When installing the new electric fuel valve, ensure that the wiring is set up correctly. Supply power to the center connection, and then run the feed to the electric valve for the auxiliary tank. This way, the switch will naturally default to the main tank, which is used most frequently.
• Consider the positioning of the fuel cell itself. While ensuring the fuel selector switch is accessible, you also want to make sure the fuel cell fits comfortably behind the seat. Take measurements of the space behind the seat and choose a fuel cell that will fit without modifications to the seat.
• Some fuel cells may require mounting with straps and rubber buffers to allow for some movement of the cell as the vehicle's body twists and turns while driving off-road. This can help prevent leaks and damage to the fuel cell.
• Finally, test the fuel selector switch and ensure it operates the new electric fuel valve correctly. You may need to make adjustments to the wiring if the switch does not align with the correct fuel tank.

By following these steps and considerations, you can ensure that the fuel selector switch remains easily accessible to the driver, even after relocating the fuel tank to a behind-seat fuel cell setup.

Verify the seat back can open/roll forward

To verify that the seat back can open/roll forward, you will need to inspect the seat and its mechanisms.

First, check that the seat back is not locked or fixed in place. Look for any levers, knobs, or buttons that may control the seat back's movement and ensure they are in the correct position to allow the seat back to move freely.

Next, try to move the seat back manually. If the seat is power-operated, ensure the vehicle is turned on so you can test the electronic controls. Try moving the seat back both electronically and manually to determine if there is an issue with the power function.

If the seat back does not move when you try to adjust it, there may be an obstruction blocking its path. Inspect the area behind the seat to ensure there are no objects preventing the seat back from opening or rolling forward.

Additionally, check for any damage or defects in the seat's mechanisms, such as broken levers, disconnected cables, or worn-out components. If the seat is power-operated, also check for any issues with the electrical connections or motors that may be preventing the seat back from moving.

If you identify any problems with the seat's mechanisms, you may need to repair or replace certain components to restore the seat's functionality.

Check for corrosion and ensure the sender works

When replacing a behind-seat fuel tank with a fuel cell, it is important to check for corrosion and ensure the sender works. Here are some detailed steps to help you with the process:

Checking for Corrosion:

• Fuel tank corrosion often occurs due to weather conditions such as heat, condensation, and UV light. It can also be caused by water formation inside the tank during warmer months, leading to bacterial contamination and sludge build-up.
• To detect corrosion, it is recommended to have fuel and tanks checked every six months by experts with confined space entry training. They will perform an internal inspection and clean the tank to expose any corroded areas.
• Additionally, Non-Destructive Testing (NDT) is used to measure metal thickness and identify damage or anomalies in the fuel. This is an important step to ensure the health of your fuel tank.
• If corrosion is detected, consider implementing techniques to prevent further damage, such as using a double-skinned tank, applying a corrosion-resistant paint coating, or installing secondary containment.

Ensuring the Sender Works:

• A faulty sender unit or fuel gauge can cause the fuel gauge to read full or empty all the time or behave erratically. Before assuming the sender is faulty, perform some simple inspections and tests.
• Check for OBD-II trouble codes if the check engine light is illuminated. Common codes related to the fuel sending unit include P0460, P0461, P0462, P0463, and P0464.
• Inspect the fuel gauge fuses. If other gauges are also acting up, it may be a fuse-related issue. Refer to your owner's manual to locate and check the fuses.
• Test the fuel gauge using a multimeter. Set it to 20V DC and check the voltage of the fuel gauge wire. If it's not receiving 12 volts, inspect the wires for damage or loose connections.
• Test the sending unit wiring connections. Remove the unit from the tank and inspect it for damage or corrosion. Clean the connectors if necessary and ensure a good ground connection.
• Verify the input and output voltage of the sending unit using a multimeter. Refer to the service manual for the proper voltage. If the voltage is different between the two ends of the wire, there may be corrosion or poor wiring.
• Finally, check the fuel sending unit ohms. Remove the unit from the tank and manipulate the float arm while measuring resistance with a multimeter. Refer to the service manual for the correct Ohms values. If the Ohms are correct but the fuel gauge is still inaccurate, there may be a wiring issue.

Consider using a universal aftermarket tank

Universal aftermarket fuel tanks are a great option for those looking to replace their behind-seat fuel tank with a fuel cell. These tanks are designed to be used in most vehicles, providing versatility and compatibility across different car models.

One of the key advantages of opting for a universal aftermarket fuel tank is the variety of materials available. Reputable suppliers like A Plus Rod and Kustom offer universal fuel tanks in aluminium, steel, stainless steel, and poly variants. This allows you to choose the material that best suits your needs and budget.

Another benefit of universal aftermarket fuel tanks is their applicability to various vehicle types. Whether you own a pickup truck, street rod, or muscle car, these tanks can be easily adapted to your vehicle. This flexibility is especially useful if you have multiple vehicles or plan to use the tank in a custom project.

When considering a universal aftermarket fuel tank, it's important to think about the specific dimensions and capacity that will suit your needs. For example, the RCI 2161a is a popular rectangular aluminium fuel cell that has been used behind the seat of a Jeep YJ. It's important to measure the available space in your vehicle and choose a tank that fits securely, ensuring it doesn't interfere with other components or the comfort of your passengers.

In addition to the tank itself, you may also need to invest in additional components, such as fuel pumps and accessories, filler hoses and couplers, fuel lines, filters, regulators, and fittings. Some suppliers, like Tank's Inc., offer a range of these supplementary parts, making it convenient to source everything you need for your fuel system upgrade.

Frequently asked questions