Originally Posted by jimlombardi

Hi
Translator asked to create this new thread that showed the missing photos in DavidN posts 1 and 2 in the How to change a Knock Sensor.

Starting with post 1:

How to change a Knock Sensor on a Jaguar AJ27 Engine

One of the common problems of the Jaguar V8 engines is knock sensor failure.
A faulty knock sensor will set the ignition timing in full retard and you'll get only a weak performance.
The failure is accompanied by the amber warning light and a DTC Message "Restricted Performance".
A knock sensor failure has not to be a permanent problem. Intermittent failure is common, but still the sensor has to be changed to get rid of the problem.

To verify if the problem is indeed a knock sensor failure and to check whether it is Bank 1 (right side of the car) or Bank 2 (left side of the car) you'll have to get the OBD codes read out.

The codes are as follows:

P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)
P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0329 Knock Sensor 1 Circuit Intermittent (Bank 1 or Single Sensor)

P0330 Knock Sensor 2 Circuit Malfunction (Bank 2)
P0331 Knock Sensor 2 Circuit Range/Performance (Bank 2)
P0332 Knock Sensor 2 Circuit Low Input (Bank 2)
P0333 Knock Sensor 2 Circuit High Input (Bank 2)
P0334 Knock Sensor 2 Circuit Intermittent (Bank 2)

There are two knock sensors located on top of the Engine, approximately in the middle of the 4 cylinders at each bank.
To get access to the sensors the black plastic engine cover with the "Jaguar V8" imprinted on has to be removed.

There are two types of knock sensors.
The "old" ones that are of a "screw-in barrel type" and the newer ones that are just bolted on.

I describe the replacement of the bolt-on type knock sensor on Bank 2 in the following documentation on a 1999 XJ8 AJ27 engine.

Be careful!
Knock sensors are piezo electric devices that are very sensitive! If dropped, over-torqued or struck they will probably be destroyed.
As knock sensors are sensitive to a sudden temperature change they are also easily fractured by steam blasting a hot engine.
So handle the knock sensors with great care and let the engine always cool before fitting a new sensor!

Here's my How-To-Write-up...

That's where we start...



Remove the black plastic engine cover.
(It is just clipped on so just unclip the two black plastic hoses on top of the cover, bent them slightly away, and pull the cover off.)




In here's the left-hand-side knock sensor hidden...



Unplug the electrical connector of the knock sensor located at the side of the black plastic thermostat housing.





Remove the connector from the retainer clip.
(To not break the connector use a small bent tool to push the latch of the connector back and slide the connector downwards and off it's retainer clip.)

Here's my "tool" and a close-up of the connector:





"Special tool" in use...





Loosen the 13mm screw nut that holds the knock sensor.



Fill a 13mm wrench socket with grease to hold the nut in the wrench socket.



Remove the screw nut and carefully lift the wrench with the nut "glued" into it up.




Here is Post 2:

...
Get yourself two pieces of wire and bent one side into a small U-hook.




Use one U-Hook to pull up the knock sensor and with the second wire carefully guide the attached cable and it's connector out.








Here's the defective knock sensor vs a new one.



(I ordered the new ones with www.autopartswarehouse.com, Item No W0133-1655837, $27.95 free shipping to the US.
They are for a XKR but fit theXJ8 as well. Only difference is that the cable is a few inches longer than the one of the original sensor, but there is enough room to tuck it away nicely.)

Use some WD40 and a paint brush to clean the surface on which the knock sensor was/will be mounted.








Insert the connector and the wire, guide it with the U-Hook-wire towards the front and lower the knock sensor onto the bolt.




To insert the new knock sensor use the shaft of a wooden spoon (or something similar) to hold and guide the knock sensor into position.







Hold the knock sensor in place with a large screwdriver and carefully remove the wooden shaft.




Slide the connector onto the retainer clip and connect it to the harness.




Grab the wrench socket with the 13mm nut still "glued" in and carefully guide the nut onto the bolt.




Tighten the nut to hand-tight. (Torque = 20Nm or 14 lb/ft, thanks to "xjrguy" for the torque data!).

Replace the engine cover and you are done!

It took me about 15 Minutes per side but I have been there before.
(As my first DTC appeared I interchanged the knock sensors just to be sure that the knock sensor was the culprit and not some bad wiring/contact.)


Good Luck!


David

P.S.
To follow that write up is completely on your own risk!
If some damage occurs following that write-up I'm in no way responsible!


Note to translator:
I do not know what is wrong with my mediafire - the folder that has the photos that DavidN provided. Apparently there is some kind serious download issue on these photos using the links from mediafire.
I delete the folder. I uploaded all the photos a folder (DaidN photo of How to changeknock sensor) to my account on www.photobucket.com.

Jim Lombardi