Introduction
The roar of a Fox Body Mustang’s engine is a symphony of American muscle. These classic cars, built to devour asphalt, have a rich history and a loyal following. However, when it comes to building a high-performance Fox Body, one area often presents a significant challenge: fuel delivery. The factory fuel system, designed for less demanding applications, can become a major bottleneck when you start adding modifications that boost horsepower. Fuel starvation, a condition where the engine doesn’t receive enough fuel, can lead to poor performance, engine damage, and a frustrating driving experience.
This article dives deep into a crucial upgrade that addresses this very problem: the fuel tank sump. We’ll explore the limitations of the stock fuel system, explain what a fuel tank sump is and how it works, highlight the benefits of installing one in your Fox Body Mustang, offer guidance on selecting the right components, provide a detailed installation guide, and cover essential maintenance tips to ensure your fuel system performs optimally. This knowledge will empower you to build a Fox Body that not only looks amazing but also delivers the power and reliability you crave.
Understanding the Need for Improved Fuel Delivery
The stock fuel system in a Fox Body Mustang, while adequate for its original purpose, can struggle to keep pace with the demands of modified engines. Several factors contribute to this inadequacy, particularly when the goal is to significantly increase horsepower.
The original fuel tanks were engineered with a specific set of performance parameters in mind. They weren’t designed to handle the increased fuel demands of high-performance engines, large fuel pumps, and the aggressive driving styles that often accompany such builds. As the engine’s power output increases, so does its need for fuel. The stock tank and fuel lines, unfortunately, often become the weak links in the chain.
Fuel starvation is a common issue in high-performance applications with the stock fuel system, particularly during hard cornering or aggressive acceleration. Under these conditions, the fuel sloshes around inside the tank, and the fuel pump can find itself temporarily starved of fuel, especially when the fuel level is low. This can lead to a lean condition, which can be detrimental to the engine.
Additionally, the factory fuel pump is often located inside the fuel tank. In certain situations, the pump can suck air due to the lack of a robust collection point. This phenomenon, known as cavitation, can damage the fuel pump and further compromise fuel delivery.
What, then, is the solution? This is where the fuel tank sump enters the picture.
A fuel tank sump is, in essence, a low-profile reservoir that is mounted on the bottom of your fuel tank. It provides a dedicated collection point for fuel, ensuring that the fuel pump is always submerged in fuel, even during extreme driving maneuvers or when the fuel level is low. This continuous access to fuel is essential for consistent fuel delivery and engine performance. A well-designed sump is a cornerstone for a reliable fuel system upgrade in any performance application.
Advantages of a Fuel Tank Sump in Your Fox Body
Installing a fuel tank sump provides a substantial upgrade over the factory fuel system, delivering several key benefits that significantly improve performance and reliability. These advantages are especially important for those seeking to extract maximum power from their Fox Body.
One of the primary benefits is vastly improved fuel delivery. By creating a dedicated collection point at the lowest portion of the fuel tank, the sump ensures a consistent supply of fuel to the fuel pump. This continuous fuel supply prevents the fuel starvation that can plague high-performance applications, particularly during hard cornering, launches, and other situations that cause fuel to slosh in the tank. Your engine gets the fuel it needs, when it needs it.
Furthermore, a fuel tank sump contributes to enhanced fuel pump performance and longevity. By ensuring the fuel pump is always submerged in fuel, the sump mitigates the risk of cavitation, which can damage the fuel pump’s internal components. This also helps to cool the fuel pump, as the fuel circulating through the pump acts as a coolant. The result is a more reliable fuel pump and potentially a longer lifespan for the entire fuel delivery system.
Importantly, a fuel tank sump acts as a foundation for higher horsepower builds. When upgrading the fuel system, the sump is often installed to accommodate a larger, higher-flowing fuel pump. The sump’s design provides adequate fuel supply to keep up with the demands of a more powerful engine. It opens the door to significantly more power, and provides an important safeguard against fuel starvation.
Considering the Details Before Installation
Before you start the installation process, it’s crucial to carefully consider several factors to ensure a smooth and successful upgrade. These considerations include choosing the right type of sump, verifying tank compatibility, selecting a fuel pump with appropriate flow rates, and assembling the necessary tools and safety equipment.
There are several types of sumps available on the market. Bolt-on sumps are designed to be mounted on the fuel tank with bolts, making the installation relatively straightforward. Weld-on sumps, on the other hand, require welding to securely attach them to the tank. Bolt-on sumps are often a good choice for those who are not comfortable with welding. Weld-on sumps can provide a very robust and leak-proof seal.
Before purchasing a sump, confirm that it is compatible with your specific Fox Body Mustang model and year. There can be variations in tank designs across different years. Make sure you measure carefully. Compatibility is crucial for a perfect fit and optimal performance.
The choice of a fuel pump is another critical aspect of this upgrade. A higher horsepower engine will need a fuel pump with a higher flow rate. Consider your horsepower goals carefully, and select a fuel pump that can provide enough fuel for your engine’s needs. Factor in future upgrades to make sure you can support them.
The fuel lines will also need to be selected for your build. You will need to consider the size of fuel lines required to supply the fuel to the engine. Many high-performance builds utilize braided stainless steel fuel lines with AN fittings, which provide superior durability and sealing compared to standard rubber hoses and clamp fittings. These are essential when upgrading to a higher flow fuel system.
Furthermore, having the right tools and the necessary skills will make the installation significantly easier and safer. If you are opting for a weld-on sump, having experience with welding is essential. Basic mechanical knowledge and skills are required for fuel system work, including disconnecting fuel lines, wiring the fuel pump, and ensuring everything is connected properly. Make sure you have the necessary tools, like a fuel tank strap wrench, an assortment of wrenches and sockets, and safety glasses.
Safety is always paramount when working on a fuel system. Gasoline is highly flammable, so working in a well-ventilated area away from any open flames or sparks is crucial. Disconnect the battery before starting any work on the fuel tank. Have a fire extinguisher readily available. Always use appropriate safety glasses and gloves.
Putting It All Together: Step-by-Step Installation
Now that you’ve considered all the important factors, it’s time to install the fuel tank sump. The steps below will guide you through the process. Remember to always prioritize safety and consult the manufacturer’s instructions for your specific sump and fuel pump.
The first step is always preparation. Ensure your vehicle is parked on a level surface, and disconnect the negative battery terminal. Drain the fuel tank. You can siphon the fuel, or the fuel tank might have a drain plug at the bottom. It’s always a good idea to have a container ready to catch any spilled fuel.
Next, remove the fuel tank. This typically involves disconnecting the fuel lines, the sending unit wiring, and any vent hoses. If your vehicle is equipped with fuel tank straps, you may need to use a specialized tool to release them. Gently lower the fuel tank from the vehicle. Clean the area around the fuel tank thoroughly.
Now, it’s time to install your selected sump. The procedure changes a little depending on whether it’s a bolt-on or weld-on type.
If you have a bolt-on sump, start by cleaning the area on the bottom of the fuel tank where the sump will be mounted. Position the sump and align it according to the manufacturer’s instructions. Install the bolts and tighten them to the recommended torque specifications. It’s important to create a good seal.
If you have a weld-on sump, you must first clean the area on the fuel tank where the sump will be welded. The tank should be free of fuel vapors. You will need to follow all welding safety precautions. Use a MIG welder to weld the sump to the fuel tank, following the manufacturer’s recommended welding procedure. It’s best to weld in short, overlapping passes to minimize heat buildup and potential damage to the tank.
After welding, it’s crucial to perform a pressure test to check for any leaks. This can be done by pressurizing the tank with compressed air (be very careful and use a low pressure) and checking for any bubbles or leaks around the weld.
Once the sump is secured, you can start connecting the fuel lines and the fuel pump. Attach the fuel lines to the sump and the fuel pump, using the appropriate fittings and sealing methods. Make sure all connections are tight and leak-free.
Next, wire the fuel pump. Connect the pump’s power and ground wires to the vehicle’s electrical system, ensuring the wiring is properly fused and protected. The fuel pump may be controlled by a relay that is activated by the ignition system. Consult a wiring diagram for your specific vehicle.
Finally, it’s time to reinstall the fuel tank. Carefully place the tank back in position, connect the fuel lines, and connect the sending unit wiring and vent hoses. Refill the fuel tank, and inspect for any leaks around the sump, fittings, and fuel lines.
Start the engine and let the fuel pump prime. Listen for any unusual sounds, and double-check for leaks. Your fuel system will be primed and ready for action.
Maintenance and Troubleshooting for Long-Term Reliability
Once the fuel tank sump is installed, proper maintenance is essential to ensure its long-term reliability and optimal performance. Regular inspections, preventative maintenance, and proactive troubleshooting can help prevent problems.
Regularly inspect your fuel filter. The fuel filter is a vital component of the fuel system. Over time, it will accumulate debris and contaminants, which can restrict fuel flow and damage the fuel pump. Inspect and replace the fuel filter at the intervals recommended by the manufacturer. It’s much cheaper to replace than the fuel pump itself.
Conduct routine inspections for fuel leaks. Walk around the fuel tank area, sump, and fuel lines looking for any signs of leakage, such as fuel stains or drips. Any leaks should be addressed immediately to avoid a fire hazard and prevent fuel system issues.
Pay attention to the fuel pump. Listen for any unusual noises or changes in the fuel pump’s operation. A failing fuel pump might make whining, clicking, or grinding sounds. Any sudden changes in fuel pressure or engine performance could indicate a problem with the fuel pump.
Common problems include fuel leaks, fuel starvation, and fuel pump failure.
If you experience a fuel leak, first, identify the source of the leak. Tighten loose fittings, or replace any damaged lines or components. If the leak is from the sump itself, check the bolts or the weld (if applicable).
If you experience fuel starvation, it could be due to a clogged fuel filter, a failing fuel pump, or an inadequate fuel supply. Inspect the fuel filter, and replace it if needed. Check the fuel pump’s voltage and make sure it’s receiving the proper power.
Fuel pump failure is often caused by cavitation, overheating, or wear and tear. If your fuel pump fails, replace it with a new one.
Conclusion
The fuel tank sump is a critical upgrade for any Fox Body Mustang owner who is looking to increase their engine’s power output and achieve reliable performance. By addressing the limitations of the factory fuel system, a well-installed sump provides a consistent fuel supply, enhances fuel pump performance, and supports higher horsepower builds. With its many benefits, it’s a key component in building a high-performance Fox Body Mustang.
Take the time to assess your power goals and the needs of your engine. Research the various sump and fuel pump options available. Take the necessary precautions to ensure a safe and successful installation.
By following the guidelines outlined in this article, you can successfully install a fuel tank sump, giving your Fox Body the fuel delivery it deserves. Unleash the full potential of your Mustang!
Additional Resources
You can find high-quality fuel tank sumps from many reputable manufacturers, such as Aeromotive, Holley, and Fore Innovations. Search online for “fuel tank sump Fox Body” for specific product listings.
YouTube is an invaluable resource. Search for installation videos by typing “Fox Body fuel tank sump installation”.
Many online forums are dedicated to Fox Body Mustangs. These forums provide a wealth of information. Search for “Fox Body Mustang forum” to find a community of enthusiasts.