Replacing Fuel Rail In Evo 9: Step-By-Step Guide

The fuel rail is an essential component of a car's fuel system, delivering fuel to the injectors. Upgrading the fuel rail in an Evo 9 can improve performance and enhance the visual appeal of the engine. This process involves replacing the original stock rail with an aftermarket option, which often has a larger diameter to increase fuel flow and support higher horsepower. The Radium Engineering Fuel Rail Kit (Evo 4-9) is one such example, offering a more substantial bore to cater to fuel-hungry engines. This kit also includes fittings and hoses to facilitate the replacement process. Additionally, some Evo 9 owners opt to replace the factory bolts securing the fuel rail with titanium alternatives, reducing weight and adding a unique aesthetic touch to their vehicles.

The benefits of an aftermarket fuel rail

Upgrading to an aftermarket fuel rail can bring several benefits to your Evo 9. Here are some advantages to consider:

Improved Performance

An aftermarket billet fuel rail is designed to provide better fuel flow and pressure regulation. The stock fuel rail can be restrictive, especially for high-performance engines. With an aftermarket fuel rail, the fuel delivery is more efficient, allowing a higher volume of fuel to reach the engine's combustion chamber. This can result in increased torque and power.

Enhanced Durability

The aftermarket billet fuel rails are made from high-quality aluminum, which provides better corrosion resistance. They can withstand the harsh conditions of the engine bay, making them suitable for high-performance engines with high temperatures and pressure. The billet fuel rail is also designed to last longer, reducing the need for frequent replacements.

Improved Fuel Ignition

Aftermarket fuel rails can improve fuel ignition by offering better fuel flow. The enhanced flow delivers fuel to the combustion chamber more quickly and efficiently, improving the engine's combustion process. As a result, you'll experience increased horsepower and torque.

Environmental Benefits

Upgrading to an aftermarket fuel rail can lead to better fuel economy and reduced exhaust fumes. This upgrade can help optimise your engine's performance while also reducing your environmental impact.

Customisation and Aesthetics

Aftermarket fuel rails come in various materials and designs, allowing you to customise the look of your engine bay. Some enthusiasts choose to upgrade their fuel rails for aesthetic purposes or to add a "bling" factor to their engines.

Step-by-step installation instructions

Step 1: Purchase the necessary parts for the installation. This includes the fuel rail kit, which typically includes the fuel rail, adapters, hoses, and other necessary components.

Step 2: Remove the engine cover and locate the fuel rail on the engine.

Step 3: Disconnect the fuel lines and any electrical connections attached to the fuel rail. Make sure to relieve the fuel system pressure before proceeding.

Step 4: Unbolt and remove the factory fuel rail. Keep the bolts and hardware organized, as you will need them for the new fuel rail installation.

Step 5: Compare the new fuel rail with the factory fuel rail to identify any differences in fittings or connections. Ensure that all necessary adapters and fittings are included in your kit.

Step 6: Begin installing the new fuel rail. Secure it in place using the appropriate bolts and hardware. Make sure the fuel rail is firmly attached and all connections are secure.

Step 7: Connect the fuel lines and electrical connections to the new fuel rail, following the instructions provided with your kit. Ensure that all connections are tight and secure.

Step 8: Reattach any other components that were removed during the process, such as hoses, clamps, or covers.

Step 9: Check for any leaks or issues before starting the engine. Ensure that all connections are secure and there are no signs of fuel leaks.

Step 10: Start the engine and check for proper fuel pressure and performance. Ensure that there are no leaks and that the engine runs smoothly.

Note: It is important to refer to the specific instructions provided with your fuel rail kit, as different kits may have slightly different installation processes or requirements. Always exercise caution when working with fuel systems and ensure that you have sufficient knowledge and experience before attempting any installation or modification.

Required tools and parts

The Radium Engineering Fuel Rail Kit (Evo 4-9) is a popular choice for those looking to replace the fuel rail on their Mitsubishi Lancer Evolution 4-9. This kit offers two configurations:

Rail Only:

All fittings must be purchased separately.

OEM Configuration:

• Radium Engineering EVO VIII/IX fuel rail
• M14 inverted flare adapter to adapt the OEM hard line on the firewall to -6AN male
• Pre-fabricated -6AN PTFE hose to replace the OEM rubber hose and restrictive 2-bolt flange
• -6AN adapter for connecting the PTFE hose to the fuel rail inlet port
• Custom-machined fuel pressure regulator adapter for the 3/8" NPT end port to use the OEM pressure regulator
• Aluminium -8AN O-ring plug for the centre port

In addition to the above, you may also need the following tools and parts:

• Fuel pulse damper or adapter for OEM pressure regulator
• -AN male adapter fittings
• Gauge (can be fitted directly to the fuel rail)
• Billet adapter fitting (to replace the plug in the top port if you intend to install a gauge)

For the Evo 7/8/9, the following tools and parts are available:

• STM Fuel Feed and Return Kit with Rail
• STM -6AN E85 Fuel Tank to Rail Kit
• STM E85 Fuel Feed Kit (Hard Line to Rail)
• STM Fuel Rail in Black
• AEM Fuel Rail
• Aeromotive High Volume Fuel Rail
• FIC Fuel Rail
• HKS Purple Fuel Rail
• Radium Fuel Rail
• STM -6AN Fuel Rail Fitting
• STM -8AN Fuel Rail Fitting
• STM E85 -6AN O-Ring Boss to 7mm Barb Fitting
• Mitsubishi Fuel Rail Bolt
• Mitsubishi OEM Fuel Rail Spacer
• Radium OEM FPR Fuel Rail Adapter Fitting
• Radium M14 Inverted Flare to 6AN for Mitsubishi OEM Hard Line
• Mitsubishi OEM Fuel Line Clip
• JMF Billet Fuel Rail
• DeatschWerks Fuel Rail
• Skunk2 Composite Fuel Rail
• Mitsubishi OEM Fuel Line to Rail Oring
• STM Billet Fuel Rail Spacer

For the Evo X, the following tools and parts are available:

• STM Fuel Rail Fitting
• STM Billet Fuel Rail Spacer
• AMS Evo X Fuel Rail Kit
• DeatschWerks Fuel Rail
• Mitsubishi OEM Fuel Pressure Regulator to Rail O-Ring
• Mitsubishi OEM Fuel Rail Bolt
• Mitsubishi OEM Fuel Rail Spacer
• Radium Fuel Rail
• Radium Fuel Rail Install Kit
• Radium OEM FPR Fuel Rail Adapter Fitting

Fuel rail maintenance tips

A fuel rail is a pipe that delivers fuel to the fuel injectors in an internal combustion engine. Here are some tips to help you maintain your fuel rail and keep it in good condition:

• Refer to your car's owner's manual to identify the location of the fuel rails. This will help you access and maintain them more easily.
• Use a fuel injector cleaning kit to clean the fuel injectors at the fuel rail. This can be done as routine maintenance, and there are many kits available online or at your local auto parts shop. Cleaning the fuel injectors can help improve fuel mileage and engine performance.
• When cleaning the fuel injectors, it is important to disconnect the fuel rails and the fuel regulator pressure line (if your vehicle has one). This will allow you to access and clean the injectors properly.
• To prevent excess pressure build-up, remember to remove the fuel tank cover before cleaning the fuel injectors.
• Shut off the fuel pump by removing the fuel pump relay from the fuse box. This is an important safety precaution when working on the fuel system.
• Use an air compressor attached to the fuel injector cleaning kit to set the pressure between 40-50 PSI. This will help ensure the cleaning process is effective.
• After cleaning, reattach all the components securely and correctly. Turn on your car to double-check for any leaks or strange noises, which could indicate that a part has been reinstalled incorrectly.
• Consider upgrading your fuel rail if you are making more than 700 horsepower (HP). Aftermarket fuel rails can provide better fuel flow and are easier to adapt to aftermarket fuel pressure regulators.
• If you have a high-performance application, install a fuel supply pressure gauge to ensure correct fuel pressure at all times. Too much inlet fuel pressure can damage the fuel pump and injectors.
• Regularly change your fuel filter to protect your fuel rail and injectors from damage and contamination. This is especially important if your engine sits around a lot.

Troubleshooting common issues

Upgrading your fuel rail can help you avoid issues with fuel starvation in some cylinders, which can lead to overly lean conditions. Upgraded fuel rails can also increase the flow compared to stock fuel rails. For example, the stock fuel rail on an Evo is good enough for up to 740 whp, but if you're making more power than that, an upgraded fuel rail is necessary to avoid fuel starvation.

If you're experiencing difficulty starting your engine, or the engine is operating erratically, this could be a sign of a malfunctioning fuel rail pressure sensor. The fuel rail pressure sensor operates by reading the internal pressure of the rail itself, and when it malfunctions, it can cause issues with the fuel pump and the engine may cut out during normal operation.

If you're having issues with your fuel rail, it's important to verify the condition of the fuel rail sensor by checking for any engine lights on the dash, listening for any cylinders not firing correctly, and feeling for any vibrations during engine operation. If the fuel rail sensor has completely failed, the engine may not start.

When replacing the fuel rail sensor, it's important to disconnect the battery and remove any brackets that may be in the way. You'll also need to find the schrader valve or test port on the fuel rail, open the valve to bleed off the pressure in the fuel rail, and remove the harness and mounting hardware from the fuel rail sensor.

Another common issue with fuel rails is fuel leaks. It's important to check for leaks after replacing or repairing a fuel rail, as this can lead to dangerous situations. Use a combustible gas detector to check all of the connections for any leaks and sniff the air for any fuel odors.

Additionally, if your engine light comes on after replacing the fuel rail sensor, there may be further diagnosis of the fuel system needed or a possible electrical issue within the fuel system.

Frequently asked questions