Replacing Fuel Injectors In A Nissan Pathfinder: Step-By-Step Guide

Fuel injectors are electronically-controlled mechanical devices that play a crucial role in the combustion of the air-fuel mixture in modern internal combustion engines. They regulate the amount of pressurised fuel used for each engine cycle and ensure even power across the engine. When a fuel injector fails, it can cause reduced engine performance, difficulty in acceleration, and even engine failure. This article will provide a step-by-step guide on how to replace fuel injectors in a Nissan Pathfinder, including safety precautions and tips for a successful replacement.

Average cost of replacement

The average cost for a Nissan Pathfinder Fuel Injector Replacement is between $715 and $888, with labour costs estimated between $210 and $323, and parts priced between $476 and $505. However, prices may vary depending on location and the year and model of your Nissan Pathfinder. For example, the fuel injector replacement service for a 1997 Nissan Pathfinder V6-3.3L is estimated to cost between $3146.68 and $4790.20, whereas the service for a 2018 Nissan Pathfinder V6-3.5L is estimated to cost between $3766.41 and $5799.23.

It is important to note that fuel injector replacement should be left to a professional, as there is a risk of fire and the repair can be complicated.

Signs of a bad fuel injector

Fuel injectors regulate the amount of pressurised fuel used for each engine cycle. There is one injector per cylinder in an engine. When a fuel injector fails or clogs, engine power is reduced and misfires will occur. The check engine light will turn on and, as the issue progresses, the engine may stall immediately after starting, fail to start, hesitate under throttle or vibrate roughly.

• Engine misfires and reduced power: When a fuel injector fails or clogs, engine power is reduced and misfires will occur.
• Check engine light comes on: This could be due to a number of issues, but a faulty fuel injector is one of them.
• Engine stalling: As the issue progresses, the engine may stall immediately after starting or even fail to start at all.
• Hesitation under throttle: You may experience a delay in response when you press the accelerator pedal.
• Rough idling and vibration: A faulty fuel injector can cause the engine to vibrate roughly, and you may notice your Nissan Pathfinder is idling roughly.
• Increased fuel consumption: If your vehicle is using more fuel than usual, it could be a sign that the fuel injectors are not spraying the correct amount of fuel.
• Difficulty starting the engine: This could be due to fuel leaking into the engine after the car is shut off, which is a common issue with faulty fuel injectors.
• Engine splutter and accelerator hesitation: A failing fuel injector can cause the engine to splutter and hesitate, especially during acceleration.

How to identify a bad injector

Fuel injectors regulate the amount of pressurised fuel used for each engine cycle. There is one injector per cylinder in an engine. When a fuel injector fails, it can cause a range of problems with your Nissan Pathfinder's engine. Here are some common symptoms of a bad fuel injector:

• Rough idle: When the injectors are not providing a consistent flow of fuel, the engine will operate unevenly, resulting in a rough idle.
• Poor fuel economy: The Pathfinder's PCM (powertrain control module) constantly adjusts the air/fuel ratio and timing for optimal combustion. When fuel injectors aren't functioning properly, the ratio will be off, leading to decreased fuel mileage.
• Misfires and loss of power: Bad fuel injectors can cause misfires due to an incorrect air-fuel ratio, resulting in a loss of power and acceleration.
• Difficulty starting the engine: Clogged or damaged injectors may not deliver enough fuel to start the engine, making it challenging to get your vehicle going.
• Engine stalling: A faulty injector can cause the engine to stall, especially when idling. In severe cases, the engine may not run at all.
• Poor acceleration: If the fuel injectors are not supplying the proper amount of fuel, your Pathfinder may experience sluggish performance and a lack of responsiveness when you press the accelerator.
• Unusual exhaust smell: A damaged fuel injector can release excess fuel or unburned fuel through the exhaust system, resulting in an unusual smell.
• Check engine light: A malfunctioning fuel injector can trigger a diagnostic code, illuminating the check engine light on your dashboard.
• Vibrating engine: A faulty injector can cause the engine to vibrate roughly, indicating a potential issue with the fuel injector.
• Dark grey smoke upon starting: Dark grey smoke when starting your Pathfinder may indicate fuel injector issues.
• Unusually high oil levels: Keep an eye on your oil levels, as high oil levels can be a sign of fuel injector problems.
• Strong gasoline smell in the oil: If your oil smells strongly of gasoline, it could be due to a faulty fuel injector leaking fuel.

If you suspect a bad fuel injector, it is essential to diagnose the problem correctly as symptoms can be similar to those of a failing fuel pump or clogged fuel filter. Consider checking the fuel pressure at the rail before replacing injectors to pinpoint the root cause of the issue.

How to replace a fuel injector

Disclaimer: This is a complicated process that should only be performed by a professional mechanic.

Step 1: Prepare the Vehicle

Before starting, relieve the fuel system pressure by disconnecting the fuel line (hose) and the fuel rail. Ensure the engine is cold to the touch and disconnect the battery.

Step 2: Disconnect Components

Remove any plugs connected to a wiring harness. Using pliers, disconnect the electrical connector on each injector.

Step 3: Remove the Fuel Injector

Lift the fuel rail off the intake manifold. Use fuel injector pullers to avoid damaging the injectors. Examine the injector and gently pull it back and forth to disconnect it from the fuel rail.

Step 4: Prepare the New Fuel Injector

Dip the spraying tip of the new fuel injector in some engine oil. This will wet the seals, ensure the right fitting, and help prevent leaks.

Step 5: Install the New Fuel Injector

Press the new injector back into the injector rail and reattach both to the engine. Bolt down the injector rail, reattach the fuel line and the wiring harness, and plug in the electrical connector.

Step 6: Reconnect the Battery and Test

Reconnect the battery. Adjust the key to the 'on' position and start the engine after 10-15 seconds. Once the engine drops to the idle RPM rate, turn it off. Inspect the new fuel injector for any leaks.

Symptoms of a Faulty Fuel Injector

• Reduced engine performance (periodic vibrations, difficulty accelerating)
• Check engine light is on
• Fuel leak and odor
• Reduced fuel efficiency
• Failed emissions test

Additional Information

Fuel injectors regulate the amount of pressurised fuel used for each engine cycle. There is one injector per cylinder in an engine. On average, fuel injectors tend to fail after 80,000 miles.

How to clean a fuel injector

Fuel injectors regulate the amount of pressurised fuel used for each engine cycle. When they fail or clog, engine power is reduced and misfires occur. The check engine light will turn on and, as the issue progresses, the engine may stall immediately after starting, fail to start, hesitate under throttle or vibrate roughly.

To clean a fuel injector, you should start by working with a cool engine in a well-ventilated area. First, locate the injectors and disconnect the fuel pump from the engine, then disconnect the injectors from the fuel pump. Next, disconnect the fuel pressure regulator (if your engine has one) and reconnect the fuel line. Find the fuel port and attach the injector cleaner kit’s hose to it. Remove the fuel tank cap to prevent building up fuel pressure.

Start your engine and let the fuel injector cleaner work through it. This should take about 5-10 minutes. Finally, disconnect the injector cleaner kit, close the fuel tank cap, and reattach the fuel pressure regulator and the fuel pump. Turn on your car and monitor the engine's performance.

Frequently asked questions