Fuel Injector Replacement: Suzuki Ltr 450 Guide

The Suzuki LTR 450 is a powerful ATV, but like any vehicle, it requires regular maintenance to keep it in top condition. One important task is ensuring the fuel injectors are clean and functioning correctly. This guide will take you through the steps to replace the fuel injectors on your LTR 450, so you can keep your all-terrain vehicle running smoothly.

Disconnect the battery

Disconnecting the battery is an important first step when changing the fuel injector on your LTR 450. This is a safety precaution to prevent any accidents or issues while you work on the engine.

Before you begin, ensure you have the necessary tools and safety equipment. You will need a ratchet and socket set, a flathead screwdriver, and pliers. It is also important to wear gloves and eye protection when working with fuel systems.

Now, locate the battery and identify the negative and positive terminals. It is important to disconnect the negative terminal first. Use the appropriate socket from your ratchet and socket set to loosen the clamp or bolt holding the terminal in place. Once it is loose, carefully move the terminal away from the battery post. You can cover the terminal and post with electrical tape or a plastic bag to prevent accidental contact.

Next, disconnect the positive terminal following the same steps. Ensure that both terminals are secure and cannot accidentally touch the battery posts. With the battery disconnected, you can now proceed with the rest of the fuel injector replacement process. Remember to reconnect the battery correctly once you have finished the work, ensuring that the positive and negative terminals are attached to their respective posts.

It is always important to take safety precautions when working with any vehicle, especially when working with the fuel system and battery. By taking your time and following the correct procedures, you can help ensure a safe and successful fuel injector replacement on your LTR 450.

Remove the top intercooler pipe

To remove the top intercooler pipe from the throttle body, you will need to disconnect the battery. This is a safety precaution to take before you start. Next, remove the plastic engine covers using the appropriate socket and set them aside.

Now, you can focus on the top intercooler pipe. First, use pliers to disconnect any electrical connectors attached to the pipe. Then, carefully lift the pipe away from the throttle body, ensuring that you do not use excessive force that could deform or bend the pipe. It is important to pull straight up for easier removal.

Once the top intercooler pipe is removed, you can continue with the next steps, such as removing the crankcase breather, oil breather, and vacuum hose from the fuel pressure regulator. Remember to refer to a repair manual for your specific vehicle to ensure you are following the correct procedure.

Remove the crankcase breather

To remove the crankcase breather on a Suzuki LTR 450, you will first need to disconnect the battery. Then, remove the top intercooler pipe from the throttle body, followed by the crankcase breather itself, which is located at the back of the throttle body. You will also need to remove the oil breather from the front of the throttle body, the vacuum hose from the fuel pressure regulator, the throttle body connection, the inlet manifold vacuum pipe, the IAT sensor connection, and the MAP sensor connection.

• Chock the front wheels of your LTR 450.
• Look under the vehicle, just in front of the rear wheel, for the sub-frame mounting bolts.
• Use an E18 socket to loosen these bolts, winding each until approximately 1/2 to 1 inch of thread is showing.
• Slowly jack up the vehicle until the rear wheel lifts off the ground.
• Now, loosen the corresponding engine subframe bolt at the rear, and slowly lower the vehicle until you have enough room to work. You may also need to slightly loosen the two nearside subframe bolts to allow for more movement.
• Remove the vacuum pipe from the fuel pressure regulator.
• Remove the connection to the throttle body.
• Reach around the back of the pipes and remove the rubber joining pipe from the crankcase. You may find it helpful to have an assistant pull on the remaining pipe section.
• Install the new pipe by reaching around the back and pushing it onto the connection. Ensure that the routing and angle of the pipes are correct, so that there are no twisting forces on the rubber joiners, which can cause premature failure.
• Reconnect the pipe to the throttle body.
• Reattach the vacuum pipe to the fuel pressure regulator.
• Raise the engine back up to the subframe and tighten the bolts.
• Lower the jack and remove the chocks.
• Finally, check that all subframe bolts are tight.

Please note that this procedure may vary depending on whether your LTR 450 is equipped with air conditioning. If you have air conditioning, you will have less space to work with, and the breather pipe connects to the crankcase just to the offside of the a/c pipes.

Loosen bolts and brackets holding the fuel rail

To loosen bolts and brackets holding the fuel rail, you will need to identify the correct bolts to loosen. In this case, there are two E10 bolts holding the fuel rail to the inlet manifold. These bolts can be loosened with the correct-sized wrench or socket. It is important to be careful when loosening these bolts, as they are holding the fuel rail in place, and you don't want to drop them into the engine.

Once the bolts are loosened, the fuel rail can be carefully tilted down to collect any remaining fuel in a small pot. The rail can then be swung back, and the injectors can be unplugged from the rail and their respective coils.

If the bolts are extremely tight, you may need to use a breaker bar or a long ratchet handle to get more leverage. In some cases, you may need to use a left-handed drill bit to loosen the bolts or even drill them out if they are seized. If the bolt head has snapped off, you can try grinding a slot in the remaining bolt piece to turn it with a screwdriver.

It is important to note that you should not drive the vehicle if the fuel rail bolts are loose or missing, as this can be dangerous.

Reassemble the manifold

To reassemble the manifold, you will need to reconnect all the lines, pipes, and leads. Ensure that the torque settings for the fuel rail to the inlet manifold are 8Nm, and the torque settings for the inlet manifold to the cylinder head are 12Nm, then 10Nm respectively.

First, carefully tilt the fuel rail to the right with a small pot to collect the remaining fuel. Swing back the whole rail, then plug in the new injectors to the rail and their respective coil.

Next, secure the fuel rail to the inlet manifold with the two E10 bolts. Reattach the inlet manifold using the seven remaining E10 bolts.

Finally, reconnect the inlet manifold vacuum pipe, IAT sensor connection, and MAP sensor connection.

Frequently asked questions