Replacing Volvo 850 Turbo Fuel Injectors: Step-By-Step Guide

If you're looking to replace the fuel injectors in your Volvo 850 Turbo, there are a few things you should know. Firstly, the cost of this replacement will depend on the year of your car and whether you choose to service or replace the injectors. On average, the cost for a Volvo 850 Fuel Injector Replacement is $657, with $562 for parts and $95 for labor.

There are several signs that indicate it's time to replace your fuel injectors, including rough idle, loss of power, misfiring, odor of raw gas or visible leaks, and a check engine light. It is important to address fuel injector issues promptly to avoid further damage to your engine.

When replacing the fuel injectors, you will need to relieve the pressure within the fuel rail, remove the upper plenum and any cables or hoses restricting access, disconnect the supply and return lines, and remove the electrical connectors. The injector requiring replacement can then be taken out, taking care not to allow debris to enter the exposed openings. A new O-ring should be used when re-inserting the serviced or replaced injector into the fuel rail.

It is recommended to service or replace all the injectors at once to ensure a balanced set, promoting smooth engine operation. Additionally, high-quality gasoline may reduce deposits on fuel injectors and prolong their life.

Fuel injector nozzles and optimum atomisation

Fuel injectors are an essential component of modern engines, with their design and performance influencing the engine's overall efficiency and emissions. The fuel injector nozzles play a critical role in this regard, as they are responsible for atomising the fuel into a fine mist before it is injected into the engine. This process of fuel atomisation is key to achieving smooth and efficient combustion with minimal emissions.

The design of fuel injector nozzles can vary, but they typically consist of a metal injector tip with tiny holes, through which the pressurised fuel is forced to create the atomised spray. The size and geometry of these nozzle holes, as well as the injector seat and sac, are crucial parameters that affect the combustion characteristics and emissions of the engine. For example, in diesel engines, the nozzle hole size and geometry impact the fuel spray pattern, which in turn affects the combustion process and the resulting emissions.

The number and position of the fuel injector nozzles are also important considerations. In fluidized bed combustion, for instance, the position of the nozzle is optimised between the need to avoid agglomeration (shallow nozzle) and the need to increase the residence time of the fuel and its vapour (deep nozzle). Additionally, the number of nozzles per unit cross-sectional area can impact the feeding and dispersion of the fuel, with too few nozzles potentially leading to agglomeration and inefficient combustion.

The type of fuel injector nozzle can also influence engine performance and emissions. For instance, the so-called "mini-sac" fuel nozzle, which has a reduced sac volume compared to a conventional fuel nozzle, has been shown to positively impact the cleanliness of the combustion chamber and reduce the formation of NOx during combustion.

Fuel injector O-rings

The fuel injector O-rings are an essential component of your Volvo 850 Turbo's fuel injection system. They are responsible for creating a seal between the fuel injector and the fuel rail, ensuring a tight fit and preventing fuel leaks. Over time, these O-rings can become worn out, brittle, or damaged, leading to fuel leaks and potential performance issues. Therefore, replacing them is crucial for maintaining optimal engine performance and fuel efficiency.

When replacing the fuel injectors on your Volvo 850 Turbo, it is highly recommended to install new O-rings specifically designed for this purpose. These O-rings are available as part of a fuel injector repair kit or as individual components from various automotive retailers. It is important to select O-rings that are compatible with your Volvo's make, model, and year to ensure a precise fit.

The process of replacing the fuel injector O-rings involves the following steps:

• Purchase the correct O-ring kit or individual O-rings for your Volvo 850 Turbo. Ensure they match the original specifications for size and material.
• Locate the fuel injectors on your engine. They are usually found on the fuel rail, which is connected to the engine's fuel system.
• Carefully remove the old fuel injectors, taking note of their orientation and any retaining clips or clamps. Place them in a safe location, as you may need to refer to them during the reinstallation process.
• Inspect the old O-rings for any signs of damage, cracks, or wear. This will help you determine if they need replacement.
• Remove the old O-rings from the fuel injectors. You may need to use a small tool, such as a flat-head screwdriver, to carefully pry them out without damaging the injectors.
• Clean the fuel injectors and the area where the O-rings sit. Ensure there is no dirt, debris, or residue that could interfere with the seal.
• Install the new O-rings onto the fuel injectors. Ensure they are seated correctly and securely in place.
• Reinstall the fuel injectors onto the fuel rail, ensuring they are properly aligned and secured in place.
• Once installed, carefully inspect the area for any signs of fuel leaks. If leaks are detected, double-check the O-rings' positioning and ensure there is no damage.

By following these steps and using the correct O-rings, you can ensure a proper seal and maintain the performance and efficiency of your Volvo 850 Turbo's fuel injection system.

Fuel injector servicing vs replacement

Fuel injectors are an essential part of your vehicle, helping it start and run smoothly. Over time, they can become dirty and lose their effectiveness, creating substantial performance issues. A fuel injection service is a detailed maintenance process where a mechanic inspects, cleans, and repairs the various components of your fuel injectors.

A complete fuel injection service involves several steps:

• Evaluation of the fuel pump pressure/volume
• Inspection of the pressure regulator, vacuum lines, and fuel rail
• Flushing of the fuel rail, fuel injector screen, and air passages
• Cleaning of all fuel injectors
• Engine computer checkup to ensure the right air/fuel mixture is flowing through the system

Most mechanics recommend a fuel injection service every few years or after a certain number of miles (usually around 45,000). This can vary depending on the vehicle manufacturer, so it is always best to refer to the owner's manual for specific recommendations.

Servicing your fuel injectors can help improve fuel economy, engine performance, and reduce exhaust pollution and repair costs. It is a relatively affordable service, typically ranging from $50 to $80, depending on the vehicle's make and model.

On the other hand, replacing your fuel injectors can be more costly. For example, remanufactured fuel injectors can cost three times more than simply servicing your current injectors. In some cases, like with the Volvo 850, replacement fuel injectors may be the only option if the original injectors are damaged or beyond repair.

In summary, while fuel injector servicing and replacement both aim to improve the performance of your vehicle's fuel system, servicing is a more affordable and preventative measure, while replacement is typically done when injectors are severely damaged or malfunctioning.

Fuel injector leaks

• Check the O-rings: Fuel injector leaks can often be traced to faulty or worn-out O-rings. Inspect the O-rings on the fuel injectors and replace them if necessary. It is recommended to replace all the O-rings, both top and bottom, as they are inexpensive and ensure a better seal.
• Inspect the Fuel Rail: The fuel rail is the metal tube that supplies fuel to the injectors. Ensure that it is securely connected and there are no leaks at the connection points. If the fuel rail bolts are loose or missing, tighten them or replace them if necessary.
• Check the Injector Nozzles: In some cases, the injector nozzles may be the source of the leak. Inspect the nozzles for any signs of damage or blockage. If the nozzles are clogged, they may need to be cleaned or replaced.
• Fuel Line Leaks: Leaks can also occur in the fuel lines, especially where they connect to the fuel rail or the injectors. Check for any signs of dampness or fuel accumulation around the fuel lines and connections.
• Pulsation Attenuator: Some Volvo models have a pulsation attenuator or pulse regulator in the fuel line near the firewall. This component can develop leaks over time due to rust or damage. Inspect this area for any signs of fuel leakage.

When working with fuel injectors and fuel lines, it is important to relieve the pressure in the fuel system before beginning any repairs. Always refer to a qualified mechanic or a Volvo service manual for specific instructions on replacing fuel injectors and addressing leaks in your vehicle.

Fuel injector electrical failures

Fuel injectors are responsible for delivering fuel to the engine. Electrical failures in the fuel injectors can cause the engine to not start or perform poorly. Here are some common electrical issues with fuel injectors and their potential causes:

• No injector pulse: This issue can be caused by a faulty fuel injector relay, cam position sensor, crank sensor, or issues with the Engine Control Unit (ECU). It is important to check the wiring and connections to these components and replace any faulty parts.
• Voltage issues: Ensuring that the fuel injectors are receiving the correct voltage is crucial. Use a voltmeter to measure the voltage at the injectors. If the voltage is inconsistent or absent, it could indicate a problem with the wiring, fuses, or the fuel injection relay.
• Grounding issues: Injectors require a good ground connection to function properly. Corroded or loose connections at the intake manifold can cause grounding issues, leading to injector misfires or poor engine performance.
• ECU problems: The ECU plays a vital role in controlling the fuel injectors. A faulty ECU may not provide the necessary ground signal to the injectors, resulting in fuel delivery issues.
• Faulty sensors: Various sensors, such as the intake air temperature sensor and manifold air pressure (MAP) sensor, play a role in fuel injection systems. If these sensors fail or provide incorrect readings, it can affect the performance of the fuel injectors.

To diagnose electrical issues with fuel injectors, it is important to perform thorough checks of the entire fuel injection system, including voltage and ground connections, sensors, relays, and the ECU.

Frequently asked questions