Replacing Fuel Injectors In 1999 Toyota Tacoma Trucks

If you're experiencing issues with your 1999 Toyota Tacoma's fuel injector, it may be time for a replacement. Fuel injectors are fuel management components that spray atomized fuel into your car's engine, and they can be either mechanical or electronic. Newer models like the 1999 Toyota Tacoma are fitted with electronic fuel injectors. While fuel injectors typically fail after 80,000 miles and don't need frequent replacement, you may need to replace yours if you're experiencing issues such as engine misfires, low fuel economy, acceleration deficits, a fuel smell, or a Check Engine Light that keeps lighting up.

Replacing a fuel injector can be a complex task and is not recommended as a DIY job due to the risk of fire and the potential for further vehicle damage if the repair is done incorrectly. It's best to leave this to a professional mechanic. The cost of replacing a fuel injector can vary depending on your location, but on average, you can expect to pay around $946, with $736 for parts and $210 for labor.

Disconnecting the fuel injector from the fuel rail and electrical connector

Step 1: Relieve the Pressure in the Fuel Rail

Before beginning any work on the fuel system, it is essential to relieve the pressure in the fuel rail. This can be done by briefly running the engine with the fuel pump fuse removed. This step is crucial for safety and should not be skipped.

Step 2: Remove the Upper Plenum and Any Obstructing Components

Locate and remove the upper plenum on the intake manifold, along with any cables, hoses, or wiring that may restrict access to the fuel injector and fuel rail. Make sure you have a safe and accessible workspace.

Step 3: Disconnect the Supply and Return Lines

The supply and return lines will need to be disconnected from the fuel rail. Carefully remove these lines, ensuring not to damage any components or cause fuel leakage. Place them safely aside.

Step 4: Disconnect the Electrical Connectors

The electrical connectors to each fuel injector will need to be unlocked and removed. These connectors supply power to the fuel injectors, so it is important to disconnect them before proceeding. Take note of their orientation for proper reassembly.

Step 5: Unbolt the Fuel Rail

With the supply and return lines, as well as the electrical connectors, disconnected, you can now unbolt the fuel rail from the intake manifold. Carefully lift or slide the fuel rail out, exposing the fuel injectors. Be cautious not to damage any components or allow debris to enter the exposed openings.

Step 6: Remove the Fuel Injector

At this point, you should be able to access the fuel injector that requires replacement. Gently remove it from the fuel rail, taking care not to damage the O-ring seal or allow debris into the opening. The O-ring seal typically holds the injector firmly in place, so you may need to use a suitable tool to carefully pry it out.

Remember to exercise extreme caution when working with the fuel system. Ensure proper ventilation and take the necessary precautions to prevent fires or injuries. If you are uncomfortable or unfamiliar with any part of this process, it is best to consult a professional mechanic.

Removing the intake manifold

To remove the intake manifold from a 1999 Toyota Tacoma, you'll first need to relieve the pressure within the fuel rail by briefly running the engine with the fuel pump fuse removed. Next, remove the upper plenum on the intake manifold, along with any cables, hoses, or wiring that restricts access.

Now, you can remove the fuel rail. First, remove the supply and return lines from the fuel rail, then the electrical connectors to each fuel injector. With these disconnected, you can unbolt and remove the fuel rail from the intake manifold. Be careful, as when the fuel rail is separated from the injectors, gasoline will leak out. Make sure to ventilate the area and take the necessary precautions to avoid any risk of fire.

With the fuel rail removed, you can now pull the injectors out of the intake manifold. Pull and use a slight twisting motion, and they should come out easily.

Now, drain the coolant by loosening the petcock at the bottom of the radiator. Don't fully remove the plug. Remove the hose clamp and separate the top radiator hose from the fitting on the intake manifold.

The plastic timing belt cover is held on by six bolts, but only five need to be removed. The hardest one to reach is the lower bolt on the passenger side, but this can be left in place. With the other bolts removed, the cover can be pulled out of the way.

The intake manifold is held to the heads with eight bolts. These bolts have a torx head within the hex bolt. After these are removed, there are four nuts on studs holding the manifold in place, one at each corner. There is also a bracket held onto the intake manifold with two bolts that needs to be removed.

Finally, there is one last nut holding the intake manifold in place. It is located on the rear driver side of the manifold and secures the fuel line. With this removed, the intake manifold can be lifted off the studs and removed.

Diagnosing a faulty fuel injector

• Engine Misfires: A faulty fuel injector can cause the engine to misfire, making the motor feel like it is sputtering and sending vibrations through the car. This happens when the delicate balance between fuel and air entering the engine is disrupted.
• Rough Idling: If your vehicle sputters and shakes when idle, it may be a sign of a faulty fuel injector. Rough idling is characterised by varying RPMs, even when your foot is off the gas pedal. It can also be accompanied by engine stalling, where the RPMs and engine noise suddenly stop, feeling like the car has run out of gas.
• Poor Gas Mileage: Faulty fuel injectors can lead to decreased gas mileage, causing more frequent visits to the gas station.
• Unstable RPM Needle: A faulty fuel injector can cause the needle on the tachometer (RPM gauge) to move erratically, indicating changes in RPM when the car isn't switching gears.
• Engine Won't Start: In rare cases, issues with the fuel injector can lead to engine failure and prevent your car from starting.
• Check Engine Light: The check engine light on your dashboard may illuminate, indicating a dirty or malfunctioning fuel injector. This can lead to a decrease in overall engine performance and fuel economy.
• Fuel Leak: Over time, heat and moisture can cause cracks in the rubber seals or the fuel injector itself, leading to a fuel leak. If you suspect a fuel leak, it is important to check the condition of your fuel injector.
• Engine Does Not Reach Full RPM: A faulty fuel injector can prevent the engine from reaching its full RPM, affecting the vehicle's performance.
• Increased Fuel Consumption: If your car is consuming more fuel than usual, it could be a sign that the fuel injectors are not functioning optimally.
• Rough Engine Performance: A faulty fuel injector can cause the engine to run roughly, with surging and bucking under various throttle loads.
• Smoke from the Tailpipe: If you notice smoke coming from the tailpipe, it could be an indication of a faulty fuel injector causing an overly rich fuel-air mixture.
• Engine Knock or Detonation: A faulty fuel injector can lead to engine knock or detonation, which, if left unchecked, can result in catastrophic engine failure.
• Odor of Raw Gas or Visible Leaks: If you smell fuel around your car or notice visible leaks, it could be a sign of a leaking fuel injector. It is important not to start the car in this case due to the fire hazard.
• Check Engine Light Illuminated: A faulty fuel injector can cause the check engine light to illuminate, indicating that there is an issue that requires immediate attention.

Choosing a replacement fuel injector

Fuel injectors are designed to deliver fuel into the engine’s cylinders at the precise moment and in the correct quantity, ensuring optimal combustion. They are a small electric valve fitted between the fuel rail and the intake manifold, combustion chamber, or throttle body.

When choosing a replacement fuel injector, it is important to consider the following:

• Type of fuel injector: There are different types of fuel injectors available, such as port fuel injectors and direct fuel injectors. It is important to choose the correct type that is compatible with your vehicle.
• Vehicle compatibility: Not all fuel injectors are compatible with all vehicles. It is important to choose a fuel injector that is specifically designed for your vehicle's year, make, and model.
• Quality: It is important to choose a high-quality fuel injector from a reputable manufacturer. This can help ensure that the injector will perform optimally and last for a long time.
• Price: Fuel injectors vary widely in price, ranging from under $50 to several hundred dollars. It is important to consider your budget when choosing a replacement injector.
• Symptoms of failure: There are several signs that can indicate a failing fuel injector, such as rough idle, loss of power, misfiring, and a check engine light. If you are experiencing any of these issues, it is important to have the injector diagnosed and replaced if necessary.
• Maintenance: To prolong the life of your fuel injectors, it is important to follow the recommended maintenance schedule, including cleaning the fuel delivery system and injectors.
• Safety: Working on the fuel injection system can be dangerous, so it is important to take the necessary safety precautions. Always disconnect the battery, wear safety gear, and have a fire extinguisher nearby when working on the fuel injectors.
• Professional installation: Replacing a fuel injector can be a complex task, so it is often recommended to have it installed by a professional mechanic. This can help ensure that the job is done correctly and safely.

Safety precautions and risks

Before attempting to replace the fuel injector on your 1999 Toyota Tacoma, it is important to be aware of the potential risks involved and to take the necessary safety precautions. Here are some detailed instructions to ensure your safety during the replacement process:

Precautions:

• Disconnect the battery before starting any work on the fuel injection system. This will prevent any accidental electrical surges or sparks that could ignite fuel vapors.
• Allow the engine to cool down completely before beginning work. Working on a hot engine can cause burns and makes it difficult to handle certain components.
• Wear protective gear, including safety glasses, gloves, and long sleeves to protect your eyes, skin, and body from any fuel spills or debris.
• Have a fire extinguisher nearby in case of a fire. Fuel is highly flammable, and any sparks or open flames could potentially cause an explosion.
• Relieve the fuel pressure before removing any components. This can be done by pressing a valve on the fuel line or pulling the fuel pump relay and cranking the engine for a few seconds.
• Work in a clean area to prevent dirt and debris from contaminating the fuel injection system and engine.
• Follow the manufacturer's instructions for replacing the fuel injector. These instructions will provide important safety information specific to your vehicle.
• Consider isolating the engine cooling system that flows through the cylinder head. This will reduce the risk of high-temperature water escaping and causing burns.
• Check the tolerances for the injector sleeve and cylinder head to ensure a proper fit. Mismatched tolerances can lead to the injector sleeve pulling free, resulting in the release of high-temperature water.
• Use the manufacturer's lapping tool for reconditioning any sealing surfaces. This will help ensure a proper seal and reduce the risk of fuel leaks.

Risks:

• Fire and Explosion: Fuel is highly flammable, and any sparks or open flames can lead to a fire or explosion. Always disconnect the battery and relieve fuel pressure to minimize this risk.
• Burns and Scalding: The engine cooling system uses high-temperature water, which can cause severe burns if it escapes under pressure. Isolate the cooling system and wear protective gear to shield yourself from potential scalding.
• Fuel Contamination: Fuel spills or leaks can contaminate the engine, leading to performance issues and further damage. Always work in a clean area and avoid spilling fuel on any engine components.
• Electrical Hazards: Working on the fuel injection system involves electrical components, such as the engine control unit (ECU) and fuel injector solenoid. Be cautious to avoid any electrical shocks or short circuits.
• Damage to Engine: Improperly replacing the fuel injector can lead to further engine damage. Ensure you follow the correct procedures and seek professional assistance if needed.
• Carbon Monoxide Poisoning: Working in a poorly ventilated area can expose you to carbon monoxide fumes, which can be deadly. Ensure the work area is well-ventilated to mitigate this risk.

Frequently asked questions