Installing An Aem Fuel Pressure Regulator: A Step-By-Step Guide

Installing an AEM fuel pressure regulator can be a tricky task, but with the right tools and procedure, it is certainly achievable. AEM, or Advanced Engine Management, offers a comprehensive fuel system for Hondas and other high-horsepower engines, addressing common issues with fuel delivery to the injectors. The process of installation involves removing the bolt at the top of the fuel filter, dealing with the spray of fuel as the system depressurizes, replacing the stock FPR with the AEM unit, and ensuring the system is repressurized before starting the engine. Adjustments can then be made with a fuel pressure gauge, wrench, and Allen wrench. The AEM regulator is designed to be adjustable, allowing users to match regulator pressure and flow with their fuel pump output.

Removing the old regulator

Locate the fuel filter bolt at the top of your fuel filter. This will be attached to the fuel rail, which is where you will be installing your new AEM fuel pressure regulator. Before you begin, ensure you have the necessary tools, including a fuel pressure gauge, a wrench, and an Allen wrench. It is also important to have a good understanding of your vehicle's fuel system and to exercise extreme caution when working with fuel-related components.

Once you have located the fuel filter bolt, it is time to break out your tools. Loosen and remove the bolt, being cautious as fuel will spray out as the system depressurizes. This is a normal part of the process, but it underscores the importance of wearing protective gear and taking the necessary safety precautions. After removing the bolt, set it aside in a safe place, as you will need it again later.

With the bolt removed, you can now take off the old fuel pressure regulator. Be gentle and careful during this step to avoid causing any damage to the surrounding components or fuel lines. Once the old regulator is removed, wipe down the area to ensure that any residual fuel or debris is cleared away, creating a clean surface for the new installation.

Now, it's time to prepare for the new installation. Inspect the O-ring that was used with the old regulator. If it is in good condition and the correct size, you can reuse it. Otherwise, you will need to obtain a new O-ring to ensure a proper seal. Additionally, take this opportunity to inspect the fuel lines and other nearby components for any signs of damage or wear. Addressing any issues now will prevent future problems.

Finally, before proceeding to install the new AEM fuel pressure regulator, carefully review the instructions that came with your new regulator. Understanding the specific steps and requirements for your new regulator will ensure a smooth and accurate installation process. By following these detailed steps, you can confidently remove the old regulator and prepare for the installation of your new AEM fuel pressure regulator.

Installing the AEM regulator

First, locate the bolt at the top of your fuel filter and remove it. Fuel will spray out as the system depressurizes, so be cautious and prepared for this. Once the system has depressurized, remove the stock FPR (Fuel Pressure Regulator). You may need to remove two bolts from the rail to do this. Then, install the new AEM FPR in its place. Ensure that you have the O-ring and a fuel pressure gauge.

Next, hook everything back up and tighten down the bolt for the fuel filter. This is the bolt on top of the banjo bolt. Now, get into the car and turn the key to the 'ACC' position 5 or 6 times. You should hear the fuel pump priming, which indicates that the system is repressurizing. After that, you can start the car.

To adjust the fuel pressure, you will need a fuel pressure gauge, a wrench, and an Allen wrench. Remove the vacuum line from the FPR and pinch it off. This will show you the current fuel pressure on the gauge. You can then adjust the pressure as needed. It is recommended to use a dyno with a wideband to get the most accurate adjustment.

The AEM regulator is adjustable from 20 psi to the maximum output of any fuel pump. The fuel pressure is controlled by a setscrew on top of the regulator, which changes the preload on an internal spring that contacts the diaphragm. The amount of preload determines the base fuel pressure. The AEM regulator also includes interchangeable discharge ports of three different sizes (0.100-inch, 0.150-inch, and 0.200-inch) to match the output of your fuel pump.

By following these steps and paying close attention to safety, you can successfully install and adjust the AEM fuel pressure regulator.

Reattaching the fuel filter bolt

First, make sure you have the necessary tools and parts, including the fuel filter bolt, a wrench, and an Allen wrench. It is also important to work with caution and wear the appropriate safety gear, as you will be working with fuel. Before beginning this process, ensure that you have already removed the old fuel pressure regulator and installed the new AEM fuel pressure regulator.

Next, locate the fuel filter. The fuel filter bolt is typically found on top of the fuel filter. Take note of the O-ring, as it is crucial for creating a tight seal and preventing fuel leaks. Position the fuel filter bolt securely in place, ensuring that it is properly aligned with the fuel filter.

Using your wrench, begin to tighten the fuel filter bolt. Apply firm and steady pressure to ensure a tight fit. Be careful not to over-tighten the bolt, as this can damage the fuel filter or strip the threads. Once the bolt is securely tightened, check to ensure that it is properly secured and will not come loose during operation.

After tightening the fuel filter bolt, it is important to check for any signs of fuel leaks. This may involve starting the engine and observing for any leaks around the fuel filter area. If a leak is detected, immediately turn off the engine and re-inspect your work. Ensure that all connections are tight and that the O-ring is properly seated and intact.

Finally, once you have confirmed that the fuel filter bolt is securely tightened and there are no leaks, you can move on to the final steps of the installation process. This may include reconnecting any disconnected hoses or components and performing any necessary adjustments to the fuel pressure regulator. Always refer to the manufacturer's instructions or seek professional assistance if you are unsure about any part of the installation process.

Repressurising the system

First, enter the car and turn the key to the 'ACC' position 5 or 6 times. You should be able to hear the fuel pump priming during this process. This step is crucial for repressurising the system. Avoid starting the engine until you have completed this step.

Next, you will need to adjust the fuel pressure. To do this, you will require a fuel pressure gauge, a wrench, and an Allen wrench. Remove the vacuum line from the FPR and pinch it off. This action will display the current fuel pressure on the gauge. Make any necessary adjustments at this point.

For optimal results, it is recommended to use a dyno with a wideband. This setup will help you fine-tune the fuel pressure accurately. Keep in mind that you will need more than just the FPR for this tuning process.

Once you have completed the above steps and made any necessary adjustments, you can start the engine. Always exercise caution when working with fuel systems and ensure that you have the necessary tools and knowledge to perform the installation safely.

Adjusting the fuel pressure

First, ensure you have the necessary tools: a fuel pressure gauge, a wrench, and an Allen wrench. The sizes of the wrenches may vary depending on your specific setup. Start by removing the vacuum line from the FPR. This will allow you to measure the current fuel pressure using the gauge. Pinch off the vacuum line to get an accurate reading on the gauge.

Now, you can begin adjusting the fuel pressure. The AEM fuel pressure regulator has a set screw on top that adjusts the preload on an internal spring, which contacts the diaphragm. Turning this set screw clockwise will increase the fuel pressure, while turning it counterclockwise will decrease the pressure. Make your adjustments in small increments to avoid overdoing it.

It is important to note that the AEM regulator is boost dependent. For every psi of boost, the fuel pressure will increase by one psi. Therefore, you need to ensure that the regulator pressure and flow match the output of your fuel pump. AEM provides interchangeable discharge ports of three different sizes (0.100-inch, 0.150-inch, and 0.200-inch) to accommodate different fuel pump sizes. Choose the appropriate orifice size to ensure consistent fuel pressure and flow to the injectors.

To determine the correct orifice size, AEM recommends the following procedure: First, install the regulator and the fuel pressure gauge. Then, adjust the set screw in quarter-turn increments. If the pressure is challenging to adjust, the orifice size is too large for your delivery system. Conversely, if you put the car on a dyno and observe that the fuel pressure remains high for more than 0.5 seconds at idle immediately after full-throttle operation, the orifice size is too small.

By carefully following these steps and making the necessary adjustments, you can fine-tune your AEM fuel pressure regulator for optimal performance and ensure your engine receives the correct fuel delivery.

Frequently asked questions