Changing Fuel Injectors: 2001 Nissan Ultima Guide

If you're looking to replace the fuel injector on your 2001 Nissan Altima, you've come to the right place. This is a job that can be done at home with the right tools and some automotive know-how. First, you'll need to depressurise the fuel system by disconnecting the fuse for the fuel pump and cranking the engine until it dies. Be sure to check your specific model for the location of the fuel fuse. Once the fuel system is depressurised, you can begin the process of removing the fuel injector. This will involve removing the upper intake plenum, unplugging electrical connectors, and removing screws. You may also need to remove the intake manifold for better access to the fuel injector. Be very careful when handling the fuel injector, as it is under high pressure. Be sure to follow safety procedures and consult a qualified mechanic if you are unsure about any part of the process.

Disconnect the fuel pump fuse and crank the engine

Disconnecting the fuel pump fuse and cranking the engine is a critical step in changing a fuel injector in a 2001 Nissan Ultima. This step is necessary to purge the fuel lines of any fuel before proceeding with the replacement. Here is a detailed guide on how to do this:

Locate the fuel pump fuse: The fuel pump fuse in a 2001 Nissan Ultima is typically located under the dash by the driver's door. It is usually a standard-size automotive blade fuse, not a mini fuse.

Disconnect the fuel pump fuse: Before disconnecting the fuse, it is recommended to turn off the car to ensure safety. Once the car is turned off, carefully remove the fuel pump fuse from the fuse box.

Crank the engine: After disconnecting the fuel pump fuse, crank the engine. This will cause the engine to die as it runs out of fuel, preventing the introduction of gas into the cylinders and reducing the risk of a hydrolocked engine.

Ensure the engine is completely off: Cranking the engine will eventually cause it to shut down as it runs out of fuel. Make sure the engine is completely off before proceeding with the next steps in changing the fuel injector.

Re-insert the fuel pump fuse: Once the engine has died and you have completed the replacement of the fuel injector, remember to re-insert the fuel pump fuse into the fuse box. This will restore the fuel supply to the engine.

This process of disconnecting the fuel pump fuse and cranking the engine is a crucial safety measure to avoid potential engine damage. It ensures that there is no residual fuel pressure in the lines, making it safe to work on the fuel system. Always exercise caution when working with automotive fuel systems to prevent injuries and accidents.

Remove the upper intake plenum

To remove the upper intake plenum, you will need to first disconnect the fuel lines and crank the engine to release any remaining pressure in the lines.

Next, you will need to remove the upper intake plenum. This will involve unplugging electrical connectors and removing screws. Once the plenum is removed, you will have access to the fuel injectors.

Be careful when removing the plenum as there are many hoses and wires attached to it. It is also important to make sure that all the old injectors have their O-rings still on. If any O-rings are missing or damaged, they should be replaced to prevent fuel leaks.

Unplug electrical connectors and remove screws

To replace the fuel injectors in a 2001 Nissan Ultima, you will need to unplug the electrical connectors and remove the screws. Here is a step-by-step guide to help you through the process:

Step 1: Disconnect the Battery

Before starting any work on your Nissan Ultima's fuel system, it is important to disconnect the negative battery terminal to avoid any accidental sparks or electrical shorts. This is a crucial safety step that must not be skipped.

Step 2: Relieve Fuel Pressure

Next, you will need to relieve the fuel pressure in the system. This can be done by removing the fuse for the fuel pump and cranking the engine until it dies. This step is important to prevent introducing gas into the cylinders and the potential risk of a hydrolocked engine.

Step 3: Locate the Fuel Injectors

The fuel injectors are located under the upper intake plenum. To access them, you will need to remove the air intake ductwork, wiring harnesses, and other components that may obstruct your access to the fuel injectors and fuel rail. This may include disconnecting components such as the cam sensor, coolant temperature sensor, OS sensor, throttle body connection, and purge volume control valve plug.

Step 4: Unplug Electrical Connectors and Remove Screws

Now, you will focus on the fuel injectors themselves. Unplug all the electrical connectors from the fuel injectors. These connectors provide power and control signals to the injectors, and they need to be disconnected before you can remove the injectors. Additionally, remove any screws or clamps that secure the fuel injectors in place.

Step 5: Remove the Fuel Injectors

The fuel injectors are typically held in place by a retaining clip. Use a suitable tool, such as needle-nose pliers, to release the clip and carefully pull the injector out. Be cautious not to damage any surrounding components or the injector itself. The injectors may require some wiggling and gentle force to remove as they are often tightly sealed in place.

It is important to note that some models may require removing the fuel rail to access and replace the fuel injectors. The fuel rail is usually secured by a few bolts that you can remove once the electrical connectors and screws around the injectors are detached.

When removing the fuel injectors, be cautious not to lose any small parts, such as O-rings or spacers, as these are crucial for proper sealing and need to be reinstalled with the new injectors.

Step 6: Install New Fuel Injectors

To install the new fuel injectors, follow the previous steps in reverse. Ensure that all O-rings and seals are properly lubricated and seated before installing the new injectors. Reattach the electrical connectors and secure the fuel injectors or fuel rail firmly in place.

Step 7: Reassemble and Reconnect the Battery

Once the new fuel injectors are in place, carefully reassemble all the components that were removed to access the fuel system. Reattach the air intake ductwork, wiring harnesses, and any other parts that were disconnected. Finally, reconnect the negative battery terminal.

Step 8: Test the Vehicle

After completing the installation, start the vehicle and check for any leaks or unusual noises. If everything seems normal, take the vehicle for a test drive to ensure that the new fuel injectors are functioning properly.

Remember to dispose of the old fuel injectors properly or consult a specialist for recycling options.

Remove the intake manifold

To remove the intake manifold as part of changing a 2001 Nissan Altima fuel injector, follow these steps:

Firstly, remove the upper intake plenum or manifold. This will give you access to the fuel rail and injectors. You will need to unplug electrical connectors and remove screws.

Now, you need to remove the fuel rail. It is attached by two 12mm bolts. These bolts are quite tight and can be tricky to access, so you may need to use a 12mm socket with a 1/4" socket wrench and some vice grips to break them loose. Once they are loose, do not use a wrench to remove them, just your fingers.

With the bolts removed, the fuel rail is now only attached by the pressure of the gaskets on the fuel injectors. Use a long-handled needle-nose plier to gently pry it out. You will not be able to remove the rail with the injectors still attached, so remove the first three injectors and then the rail will come out.

To remove the injectors from the fuel rail, use long-handled needle-nose pliers to grab the retaining clip and push it back. Then, grab the body of the injector with the pliers, wiggling it right to left while putting pressure downward and away from the fuel rail. The injector is only held in by a rubber gasket, so it should come out with some maneuvering.

Now that the fuel rail and injectors are removed, you can replace the injector or perform other necessary maintenance. Reinstallation is the reverse of the removal process, taking care to lubricate the o-rings on the fuel injectors with motor oil to make installation easier.

Remove the fuel rail

To remove the fuel rail from a 2001 Nissan Ultima, first depressurise the fuel rail. Remove the fuel pump fuse and crank the engine until it dies. Alternatively, start the car and then remove the fuse—the car will die when the remaining fuel has been consumed.

Next, remove the upper intake manifold (UIM). You will need to unbolt a bunch of components to do this. Once the UIM is off, you can access the bolts holding the fuel rail to the lower intake manifold (LIM).

Now, disconnect the fuel rail via the quick-release clip. You will need to push on the clip part and then pull on the rail. Be careful not to use too much force, as the fuel rail is still attached by the pressure of the gaskets on the fuel injectors.

Once the quick-release clip has been disconnected, loosen the bolts holding the fuel rail in place. There should be two 12mm bolts. You can use a 1/4" socket wrench and a 12mm socket to loosen them. Be careful not to fully remove the bolts yet, as the fuel rail is still attached by the fuel injectors.

At this point, you will need to remove the fuel injectors from the fuel rail. Use long-handled needle-nose pliers to remove the retaining clip from each injector. Then, grab the body of each injector with the pliers and wiggle it from side to side while applying downward pressure to remove it from the fuel rail.

With the fuel injectors removed, you can now finish removing the bolts and take off the fuel rail. Be sure to keep the bolts and spacers safe, as you will need to reinstall them when you are finished.

Frequently asked questions