1998 Jaguar XJ non start

swarlb

Car was driving perfectly....then for some strange reason now will not start. The engine turns but will not fire. Also the car is in 'Valet Mode' which means the boot cannot be opened, either with the key or remote fob. Car car itself cannot be locked with the key fob either. At times the alarm will go off, this can be stopped by inserting the key into the ignition and turning it 'on'.
There is no handbook with the car. I believe it to be a key or keyfob issue. The batteries in the remote have been changed.
There are 4 buttons on the fob, all are worn so there is no indication of what they do. Any ideas ?

sogood

swarlb wrote: »

Car was driving perfectly....then for some strange reason now will not start. The engine turns but will not fire. Also the car is in 'Valet Mode' which means the boot cannot be opened, either with the key or remote fob. Car car itself cannot be locked with the key fob either. At times the alarm will go off, this can be stopped by inserting the key into the ignition and turning it 'on'.
There is no handbook with the car. I believe it to be a key or keyfob issue. The batteries in the remote have been changed.
There are 4 buttons on the fob, all are worn so there is no indication of what they do. Any ideas ?

What specific XJ model is it? I drive a 96 XJ6 and am a bit familiar with their oddities at this stage. Non starting can have a multitude of possible causes. Crank position sensor out of kilter, possible alarm fob issue as indicated etc. etc. You should be able to overide the valet mode by locking and unlocking the drivers door with the key. If the larm chirps when you do this, then it is still armed and can only be de-activated by putting the key in the ignition, as indicated. So, that points towards the immobiliser being suspect. The car also wont start if it is in any gear other than D or P. Sometimes the relevant microswitch beneath the ski slope (centre console) can go out of sync. Check that the letter D glows red, otherwise the switch may well be the culprit.

swarlb

The car is an XJ8 Sport (V8 3.2). I tried locking and unlocking the doors with the key. All this does is set off the alarm when the door is opened. It will not unlock the boot.
It just sounds like an engine that is trying to fire but will not 'catch'. This is why I thought there may be an immobiliser fitted.
I have read on various Jag forums that there may be a sequence of 'buttons' to press, or a method where the headlamp stalk is used for this function. But I cannot find anything specific to this model.

sogood

Yes, the sequence for setting up a fob is different for the xj8, which uses the indicator stalk, whereas the xj6 uses the fob and a sequence, incorporating the valet switch. www.jaguarforums.com is one of the best resources on the net, with specific sections for each model. Check it out and do a search and you will be innundated with information. Plus a load of xj8 owners to chime in!

Replacement fobs are easily available on ebay and can be programmed to your car as a diy job.

Bigus

It does sound like immobiliser problem , check for spark with a spare spark plug, if you have spark it's not immobiliser .


There's a good , chance it could be flooded , was it moved a short distance before this problem ?
Xj8 s are notorious for flooding , with petrol in the bores even causing lack of compression.

Recommended cure is to remove plugs and squirt a small amount of engine oil in the bores to restore compression.

However the last one I stared was a later Aluminium bodied model which I couldn't get at the plugs but I preheated the block and air intake with two hair dryers and away she went.p, after 20 mins heating.