Hi Dave @davejones

I had exactly the symptons you have described with my own 3.6 Cabriolet last year – Slow running seemed to be a random thing that the car either decided it wanted to do or not on a whim. Made driving it very hard and unpredicatble – sometimes needing to be sat at traffic lights bliping the accelerator like a boy racer to keep it going and others the car being perfectly behaved.

We swapped a the same sensors as yourself, with similar results to your own – it would work for a while then start messing aroudn again. Then one day the car wouldn’t start at all -dead 🙁

Subsequently we HAD to change the ECU to get the car going and borrowed one – and all the random yet persistent slow running issues went away. Replacing the ECU was not on the list of things to try, but I wish it had had been right at the start.

I’ve met a couple of other folk who have had similar problems and it does seem to be that if you have this random slow running issue that its cause by the ECU – when it’s a consistent and persistent slow running problem then it seems changing the sensors does fix the problem.

I’d be interested to know if others in the Club have had the same experience.

Hope this helps,

Laurence

Hi Greg @gregsouter

I don’t have the answer myself, but I have asked my local Jaguar Independent Garage to see if they can help. Below is my recollection of how it was described to me.

There is a cable, like a curly data cable, that comes from the rear axle/rear transmission and disappears into the boot area. Within the boot area there are two electronic modules, the smaller of which is the module that translates the pulse coming into it (via that cable) into a voltage. This is then taken as a wire to the dashboard and it is that voltage that gives you the speedo reading.

This means that you’ll only get the voltage out of the electronic module in the boot when the car’s moving and it’s busy translating the pulse from the rear axle.

A thought, do you have cruise control and does it work – the reason for this question is that the cruise control works from the same pulse translation provided by the electronic module in the boot. If cruise control works and the speedo doesn’t then it’s likely that the speedo is broken.

Not sure if the above is of any help, but might lead you to eliminate a few things.

Laurence

Hi Martin @ball

The Targa clips are bolted through to captive nuts that are on clips – the nuts are not spot welded in place. This allows the nut to have a certain amount of ‘float’ and therefore enabling you to adjust the position of the clip.

THe hex bolts often spin because the little retaining clip holding the nut in place slips off and just spins round and round with the nut.

So, what can you do…

Well first thing is Be Very Careful With Those Clips – they’re old and often very brittle and quite a challenge to replace.

Unfortunately there is no way to get to the captive nut without removing the trim, but if you need to do this then here’s what you need to do

1/ remove the sun visors and it’s retaining clip – again take care as can be brittle. These simply unscrew

2/ remove the rear view mirror – this is cast with some odd alloy so if you keep it supported until all screws out otherwise you’ll break a corner off.

3/ remove the hex bolts holding the clips in place – drill out the hex bolts that are spinning (which might be fun as will try spining as fast as your drill bit)

4/ remove the cover from the ‘A’ pillar (that’s the pillar down the side of the windscreen)- two screws with dish washers

5/ you’ll now be able to remove the screw that holds the padded cover that runs along the top of the door opening. This is an aluminium panel covered in roof lining.

6/ with care now you should be able to slide out of place the panel that goes across the front of the car (where you’ve just removed the sun visor, mirror and catches.

Now you’ll be able to see the cage that the retaining nuts are in, and be able to rectify with replacement clip retained nuts.

To put things back together it can be a bit of a pain getting the hex nuts to re-engage with the retained nuts (as the nuts do ‘float’ about quite a bit). I got round this by ‘lightly packing’ some tissue around the retained nuts to hold them roughly centrally in the slot. Once the Hex Bolt was engaged then it was quite easy to move the clip to adjust thier position as the tissue moved.

Hope above helps,

Laurence

2/

Hope you told the new owner of your previous Convertible about this club before they drove off in it 🙂

Its good you’ve found a replacement – so soon too.

Don’t forget to update you XJS Ownership details Bob @bob-flint with your new purchase

Laurence

Hi Mark @mark

I asked around a few places and no one has a suitable 2nd hand fuel pump. However, I’ve been told that you can get yourself a brand new one from places like ABS and BMS.

Cheers,

Laurence

Hi Jon

I think it might be worth it if you check under the rear parcel shelf cover piece – you may well find the captive nuts for the rear seatbelts, as per the orignal Coupe configuration.

Laurence