Replacing Fuel Injector In Bmw 328I: Step-By-Step Guide

If you're looking to replace the fuel injector on your 2008 BMW 328i, it's important to note that this is not a simple DIY job. Fuel injectors regulate the amount of pressurised fuel used for each engine cycle, and there is one injector per cylinder in an engine. When replacing fuel injectors, it is recommended to use high-quality, OEM parts to ensure even power across the engine and a proper air-fuel mixture for all cylinders. The average cost for a BMW 328i fuel injector replacement ranges from $350 to $1,272, with labour costs estimated between $126 and $250, and parts priced between $600 and $1,113.

Before attempting to replace the fuel injector, it is crucial to relieve the fuel system pressure to minimise fuel spillage. This can be done by removing the fuel rail pressure testing cap and pressing the Schrader valve to drain the fuel rail. The fuel supply line can then be removed by pressing the plastic collar towards the fuel line and sliding it off the fuel rail.

To access and replace the fuel injectors, the intake manifold will need to be removed. This process may involve draining the coolant and oil and removing multiple engine components. Once the fuel injector is accessible, it can be disconnected from the fuel rail and electrical connector. When installing a new injector, it is important to lubricate the sealing O-rings with silicone grease to ensure a proper fit.

It is important to note that driving with a faulty fuel injector can be hazardous. It can cause the car to stall, accelerate unpredictably, and even fail to start. Therefore, it is recommended to have a professional replace the fuel injector to ensure the job is done safely and correctly.

Disconnect the battery and relieve fuel system pressure

Disconnecting the battery and relieving the fuel system pressure is an important step when changing the fuel injector on a BMW 328i 2008. Here is a detailed, step-by-step guide on how to do this:

Step 1: Disconnecting the Battery

Before disconnecting the battery, it is important to take a few precautionary measures. First, remove the key from the vehicle and store it in a safe place. Also, make a note of your radio presets as these may be lost during the process. Once you are ready, follow these steps:

• Locate the battery: The battery in BMW E90 models is typically found in the right side of the trunk, behind a trim panel.
• Disconnect the negative (-) battery cable: Using a ratchet and a 10mm socket, carefully disconnect the negative battery cable first. Move the cable aside and cover it to prevent accidental contact with the battery terminal.
• Open the battery safety terminal cover: Release the locking clips and open the cover. There are usually two plastic locks on each side that need to be released.
• Open the battery power module cover: Release the locking clip and open this cover as well. There should be a black locking tab that needs to be pressed toward the front of the vehicle.
• Remove the battery power module nut: Use a ratchet and a 13mm socket to remove this nut.
• Loosen the positive (+) battery cable: Again, use a 10mm socket to loosen this cable.
• Remove the battery: Lift the battery power module up and out of the battery. You may need to detach the clips at the side that lock onto the battery. Be careful when handling the battery as it is quite heavy. Ensure that you keep the cables out of the way as you remove the battery.

Step 2: Relieving Fuel System Pressure

Now that the battery is disconnected, it is time to relieve the fuel system pressure. Here is how you can do this:

• Remove the fuel rail pressure testing cap: Place a rag under the port to catch any spilled fuel.
• Press the Schrader valve: Use a small flathead screwdriver to press the Schrader valve and relieve the fuel pressure. Wrap the rag around the screwdriver to minimize fuel spillage.

By following these steps, you will have successfully disconnected the battery and relieved the fuel system pressure in your BMW 328i 2008, preparing you for the next steps in changing the fuel injector. Remember to work in a well-ventilated area and wear gloves and eye protection for your safety.

Remove the fuel rail pressure testing cap

To remove the fuel rail pressure testing cap, follow these steps:

• Relieve the fuel system pressure by removing the fuel pressure test port cap and pressing the Schrader valve to drain the fuel rail.
• Place a rag under the port.
• Use a small flathead screwdriver to press the Schrader valve and relieve fuel pressure.
• Wrap the rag around the screwdriver to minimise fuel spillage.

Disconnect the fuel injector harness strip from the fuel injectors

Disconnecting the fuel injector harness strip from the fuel injectors is a crucial step in replacing the fuel injectors in your BMW 328i 2008. Here is a detailed, step-by-step guide on how to do it:

Step 1:

Locate the fuel injector harness strip. It is connected to the fuel injectors and can be found near the intake manifold.

Step 2:

Before disconnecting the harness strip, make sure to relieve the fuel system pressure. This will minimize fuel spillage during the process. The best way to do this is by removing the fuel pressure test port cap and pressing the Schrader valve to drain the fuel rail. Place a rag under the port to catch any spilled fuel.

Step 3:

Once the fuel system pressure is relieved, use a large flathead screwdriver to gently pry up at each fuel injector. This will release the spring clips that hold the electrical harness to the fuel injectors. Be sure to lever straight up and position the flathead screwdriver next to the fuel injector connector you are releasing.

Step 4:

Work your way down the injector electrical harness and disconnect each fuel injector. Gently pry up and release the spring clips one by one, ensuring a safe and controlled disconnect.

Step 5:

After all the fuel injectors are disconnected from the harness strip, set the harness strip aside and proceed with the fuel injector replacement process. Remember to work with a cool engine and take the necessary precautions when working with fuel and electrical systems.

Remove the fuel rail fasteners and pull the rail straight up and out of the cylinder head

To remove the fuel rail, you will first need to relieve the fuel system pressure. This can be done by removing the fuel rail pressure testing cap and using a small flathead screwdriver to press the Schrader valve and relieve the fuel pressure. Remember to wrap a rag around the screwdriver to minimise fuel spillage.

Next, disconnect the fuel supply line by pressing the plastic collar towards the fuel line and sliding the fuel line off the fuel rail. Place the disconnected fuel line on the valve cover, wrapped in a rag, to collect any excess fuel and keep dirt from entering the fuel line.

Now, release the fuel injector harness strip from the fuel injectors by gently prying up at each fuel injector with a large flathead screwdriver. Work your way down the injector electrical harness and disconnect each fuel injector.

Then, remove the four 10mm fuel rail fasteners. Finally, pull the fuel rail straight up and out of the cylinder head, being careful not to damage the fuel injectors. If the O-rings are stuck, you can lightly pry the fuel rail up using a flathead screwdriver. It is recommended to pry between the edge of the valve intake manifold and the fuel rail.

Remove the retaining clip and pull the fuel injector straight out of the fuel rail

To remove the retaining clip, use a flathead screwdriver to pry it free from the ring it is attached to. Then, slide the clip back to remove it from the injector. Now, simply pull the fuel injector straight out of the fuel rail.

• Using a flathead screwdriver, carefully pry the retaining clip off the injector. Be gentle to avoid damaging the clip or any other components.
• Once the retaining clip is loose, slide it back along the injector to fully remove it. Set the clip aside in a safe place so you can reinstall it later if needed.
• With the retaining clip removed, you can now pull the fuel injector straight out of the fuel rail. It may require some force, but make sure to pull it out slowly and evenly to avoid damaging the injector or the fuel rail.
• If the injector is difficult to remove, you can try using a small amount of silicone spray or a recommended lubricant to help loosen it. Do not use excessive force, as this may damage the injector or fuel rail.
• Once the injector is removed, set it aside in a safe place. If you are replacing multiple injectors, make sure to label or mark each injector to ensure proper reassembly.
• Before reinstalling a new injector, inspect the sealing O-rings and replace them if necessary. It is also recommended to lubricate the O-rings with a small amount of silicone grease or a recommended lubricant to aid in installation and prevent damage.
• When you are ready to install the new injector, simply insert it into the fuel rail, ensuring it is properly aligned and seated.
• Once the injector is in place, reinstall the retaining clip by sliding it onto the injector and securing it in place. Make sure the clip is fully engaged and seated correctly.
• Repeat these steps for each injector you need to replace.

Frequently asked questions