Replacing Fuel Rail In Jaguar S-Type: Step-By-Step Guide

Changing the fuel rail on a Jaguar S-Type can be a complex task, and it is recommended that you consult a qualified mechanic or seek expert advice before attempting any repairs. That being said, here is an overview of the process to get you started. First, it is important to gather the necessary tools and parts, including a new fuel rail, gaskets, and lubricants for the O-rings. Next, you will need to relieve the fuel pressure via the Schrader valve or by removing the fuel pump relay and attempting to start the car. Once the pressure is released, you can proceed to remove the fuel rail by undoing the retaining screws and pulling it out. It is important to note that there are different fuel rail designs for different models of the Jaguar S-Type, so be sure to consult the appropriate repair manual or seek guidance from a Jaguar forum or enthusiast community. Additionally, when reassembling the fuel injectors, it is recommended to clean everything and replace the injector seals to avoid damage.

Removing the injectors

To remove the injectors from your Jaguar S-Type, you will first need to remove the lower portion of the intact manifold which houses the injectors. This will give you access to the injectors and fuel rail. Be careful not to pry on the injectors, as this can damage the fuel injector and/or seal.

Once the manifold is removed, clean everything and replace the injector seals. Then, reassemble the lower manifold/injector assembly and refit it to the cylinder heads.

If your injectors are pointing in opposite directions, making it difficult to fit the fuel rail, you can try removing the black plastic intake runners that the injectors are fitted in. Then, fit the fuel rail and fuel rail mounting bolts, and refit the intake runners and injectors as one assembly. The gasket is reusable, but it is recommended to replace it with a new one.

Cleaning the injectors

To clean the injectors of a Jaguar S-Type, it is recommended to have a mechanic carry out a fuel injector clean. They can do this as part of your Jaguar S-Type’s service and they will know what type of cleaner works best, the amount required, and what operations to perform to get the cleaner through the fuel system effectively.

If you are experiencing issues with your fuel injectors, it is best to book in a fuel injector clean with an experienced Jaguar S-Type fuel injector technician.

There are also fuel injector cleaning products available on the market that you can use yourself. However, opinions vary on their effectiveness. Some Jaguar owners report positive experiences with products such as LiquiMoly, BG 44K, and Archoil, while others believe that modern fuels contain enough cleaner to keep the engine clean and that fuel injector cleaners are a waste of money.

Refitting the injectors

To refit the injectors, follow these steps:

Firstly, it is recommended to remove the lower portion of the intact manifold, which houses the injectors, before detaching the fuel rail. This will help avoid any potential damage to the fuel injector and/or seal. Once removed, clean all the components thoroughly and replace the injector seals. Then, reassemble the lower manifold/injector assembly and refit it to the cylinder heads.

Next, remove the black plastic intake runners that the injectors are fitted into. After this, you can proceed to fit the fuel rail and fuel rail mounting bolts. Finally, you can refit the intake runners and injectors as one assembly. It is also suggested to replace the gasket, although this is reusable.

Removing the lower intake manifold

To remove the lower intake manifold, you will need to first remove the fuel rail. This can be done by carefully rocking the rail back and forth and gently pulling up at the same time. It is important to note that you should not pry on the injectors to attempt to fit the fuel rail as this may damage the fuel injector and/or seal.

Once the fuel rail is removed, you can then remove the lower portion of the intact manifold. This will give you access to the injectors, which can then be removed. Be sure to clean everything and replace the injector seals before reassembling the lower manifold/injector assembly and refitting it to the cylinder heads.

The lower intake manifold is held in place by bolts, so you will need to remove these bolts in order to remove the manifold. Be sure to keep track of the bolts and their locations as you remove them, as this will make reassembly easier.

Additionally, there may be hoses or other components attached to the lower intake manifold that will need to be disconnected or removed before the manifold can be completely removed. It is important to be gentle and take your time during this process to avoid damaging any of the surrounding components.

Once all the bolts and attachments have been removed, you should be able to carefully lift and remove the lower intake manifold. Again, be gentle and take your time to avoid damaging any nearby components.

Replacing the fuel rail pressure sensor

To replace the fuel rail pressure sensor on a Jaguar S-Type, follow these steps:

First, relieve the fuel pressure via the Schrader valve before releasing the retaining screws. The Schrader valve is like a tyre valve and is located on the RHS rear of the fuel rail. You can also relieve the fuel pressure by removing the relay for the fuel pump and trying to start the car until it dies.

Next, remove the old fuel rail pressure sensor. It has two O-rings that seal it in place, so simply undo it and pull it out. Be careful not to drop the small bolts as they are not ferrous metal and cannot be picked up with a magnet if they fall under the intake. It is recommended to use rags to catch any dropped parts or fluids.

Now, install the new fuel rail pressure sensor. You can use rubber grease, Locktite 515, or another rubber-safe lubricant on the O-rings. Do not use Vaseline as it is petroleum-based and does not work well with rubber. Ensure that the new sensor is correctly seated and the O-rings are properly sealed.

Finally, reconnect the electrical connector to the new fuel rail pressure sensor and start the car to check for any leaks or issues.

This procedure should help improve the car's performance and throttle response, making it run like a proper "Jaag"!

Frequently asked questions