Replacing Fuel Injectors: E34 535I Guide

Replacing the fuel injectors on the E34 535i is a complex task that requires a good amount of automotive knowledge. The fuel injectors regulate the amount of pressurised fuel used for each engine cycle and there is one injector per cylinder. Before starting, it is important to disconnect the battery and take proper precautions to prevent a fire. The first step is to remove the intake manifold to access the fuel injectors. This may involve draining the coolant and oil and removing many engine components. Once the fuel injectors are accessible, they can be disconnected from the fuel rail and electrical connector. At this point, the new fuel injectors can be installed, ensuring that the intake manifold gasket is replaced and all components are securely fastened. Finally, the vehicle should be checked for fuel leaks and a DME calibration should be performed to ensure optimal engine performance.

Disconnect the air intake hose over the fuel rail

Disconnecting the air intake hose over the fuel rail is a crucial step in accessing the fuel injectors on your E34 535i. Here's a detailed guide on how to do this:

Tools Required:

• Socket wrench
• Screwdriver

Procedure:

• Locate the air intake hose: The air intake hose is connected to the fuel rail, which sits on top of the fuel injectors. It provides air to the engine and needs to be carefully removed before accessing the fuel injectors.
• Loosen the connection: Use a socket wrench to loosen the clamp that secures the air intake hose to the fuel rail. Be gentle to avoid damaging any nearby components.
• Detach the air intake hose: Once the clamp is loose, carefully pull the air intake hose away from the fuel rail. You may need to wiggle it gently to detach it completely.
• Set the air intake hose aside: Place the disconnected air intake hose in a safe location, away from any flammable materials or sources of heat.

At this point, you should have successfully disconnected the air intake hose over the fuel rail, and you can now proceed to the next steps in accessing and replacing the fuel injectors. Remember to refer to a reliable repair manual or seek assistance from a qualified mechanic if you're unsure about any part of the process.

Remove the electrical plug plate

To remove the electrical plug plate from the fuel injectors of your E34 535i, you will need a 25mm socket wrench.

First, disconnect the air intake hose over the fuel rail with a socket wrench to access the fuel rail. Then, remove the plastic caps that cover the fuel rail.

Next, remove the pair of screws that attach the electrical plug plate to the fuel injectors with your 25mm socket. Now, simply unplug the electrical plate from the fuel injectors.

At this point, the electrical plug plate should be removed. However, if you need to, you can continue with the following steps to remove the fuel injectors themselves. Disconnect the three mounting bolts on the fuel rail with a socket wrench and lift the fuel rail from the intake manifold. Detach the electrical plugs from the fuel injectors. Remove the retainers from the fuel injectors and disconnect the fuel injectors from the fuel rail.

Disconnect the mounting bolts on the fuel rail

To disconnect the mounting bolts on the fuel rail of your E34 535i, you will first need to access the fuel rail by disconnecting the air intake hose with a socket wrench. Once you have removed the air intake hose, you can then remove the plastic caps that cover the fuel rail.

With the fuel rail now exposed, you will need to locate the mounting bolts. There should be three mounting bolts attaching the fuel rail to the intake manifold. Using a socket wrench, proceed to disconnect these bolts. Be sure to have a jar and a rag ready to catch any fuel that may come out as there is still pressure in the system.

Once the mounting bolts have been disconnected, you can then lift the fuel rail away from the intake manifold, providing access to the fuel injectors for further maintenance or replacement. Remember to cap off the opening on the fuel rail to prevent any foreign material or debris from entering the fuel system.

When reinstalling the fuel rail, torque the mounting bolts to between 6.5 and 8.0 ft-lbs with a torque wrench to secure the fuel rail firmly in place.

Remove the retainers from the fuel injectors

To remove the retainers from the fuel injectors of your E34 535i, you will first need to disconnect the air intake hose over the fuel rail with a socket wrench to access the fuel rail. Next, remove the plastic caps that cover the fuel rail. Then, remove the pair of screws that attach the electrical plug plate to the fuel injectors with a 25mm socket. Now, unplug the electrical plate from the fuel injectors.

At this point, you will need to disconnect the three mounting bolts on the fuel rail with a socket wrench and lift the fuel rail from the intake manifold. Detach the electrical plugs from the fuel injectors. Finally, you can remove the retainers from the fuel injectors and disconnect the fuel injectors from the fuel rail.

If you are having trouble accessing the fuel injectors, you may need to remove the intake rubber boot first. You can use a screwdriver to release the clip on each one, moving from front to rear as you pull up gently on the plastic wiring enclosure.

Install the fuel injectors to the fuel rail

To install the fuel injectors to the fuel rail of your E34 535i, you will need to follow these steps:

Firstly, you will need to clean and lubricate the O-rings on the fuel injectors with petroleum jelly. This is important to ensure that the O-rings are in good condition and can create a tight seal when installed.

Next, you can install the fuel injectors onto the fuel rail. Make sure that the injectors are securely attached to the fuel rail before proceeding to the next step.

Once the fuel injectors are in place, you can plug the electrical connectors into the fuel injectors. Ensure that the connections are secure and that there is no damage to any of the connectors or wires.

Now, you can mount the fuel rail to the intake manifold. Torque the mounting bolts to between 6.5 and 8.0 ft-lbs with a torque wrench. It is important to ensure that the fuel rail is securely mounted before moving on.

Finally, connect the electrical plug plate to the fuel rail and fasten it in place with the appropriate screws. You may also need to replace the cover and plastic plugs for the fuel rail at this point.

By following these steps, you will have successfully installed the fuel injectors to the fuel rail of your E34 535i.

Frequently asked questions