Mine hasn't got one either. Mind you, I never expected one!

Edit: Look before using memory alone, pillock.

 

Mine hasn't got one either. Mind you, I never expected one!

Ignore this bloke, he doesn't have a clue what he is talking about, and he has a habit of posting before checking. There appears to be something under his accelerator pedal after all:

No idea if it is a kick down button or just a doorstop, but there is something unexpected there!

PS - no fancy metal pedals here!

 

Amazing. Maybe it was an option? �� ☺

 

You can buy one from the same place that sells starting handles and distributor caps .

 

Certainly one on my late 4.2. It noticeably clicks under pressure.

I always thought it was the kickdown button that was activated to disable the fuel pump to clear the flooding that was particularly associated with the earlier 4.0 nicasil engines, but maybe just full throttle did the trick?

 

Thanks for your comment.
I also thought that about the kickdown. I’ll endeavour to get one.

 

In light of the different experiences, I looked into this a bit more, particularly as thinking about it I couldn't recall noticing such a switch in any of the wiring diagrams! Checking them showed there is no such switch.

So what is the spring loaded button that clicks under the throttle pedal at full travel? I've just been out to have a look and it's a black plastic fitting that is clipped in place with a spring wire fitting (a bit like those wire clips that hold some electrical connectors together) The plastic button is a two part item with a compression spring between them. It attaches to a screwed stud in the floor under the pedal.

So it appears to be an adjustable height, spring loaded pedal stop for what it's worth.

 

That’s interesting, if somewhat disappointing. I had hoped it was more than that as the earlier models had a button with an electrical lead attached, to plug into the throttle in some way I guess?
I appreciate you’re looking. Still seems odd that they simply wouldn’t have used a rubber stop of sorts as opposed to that.
My last XK8 (51 plate) flew when kicked down. This, is not so. Maybe back to the gearbox learning a style of driving? Either way, I need a button to cover that odd stud sticking out from the carpet ☺

 

Just to add to the confusion.............

My 2003 4.2 Ltr XKR has a kickdown button. You push the pedal to the floor. It stops. It feels like that is it. Then you push down even harder pass the 'stop' and the kick down kicks in. It makes a big difference. The whole push-back-into-the-seat experience. Adds a bit of thrill to an already exciting drive. As I said it really makes a big difference.

 

Can you check for wiring etc Frank? Thee plot's thickening! I know from previous checks that my throttle opens 98% when it touches the button and the final 2% under that additional spring load. The final 2% of throttle seems an unlikely kickdown arrangement?

Does the setting of the sport button affect the matter in hand?

I'll try and do some trials tomorrow!

 

Thanks Frank. Definitely getting one and I’ll report back. Won’t be as exciting as your XKR (on my wish list), but looking forward to it all the same.

 

No wiring apparent. Just resistance at the end of pedal travel. As I said push to the end then push more. Apparently its to stop anyone accidentally flooring it and shoving it through a wall. I had it for ages before I even knew it was there.

 

I've robbed this from the American forum - the guy didn't have noticeable kickdown in a '98 - May help (although I'm not sure about that)...

Here is what the JTIS says :

Kickdown Switch (where fitted)
Kickdown is intended to provide maximum vehicle acceleration, via the appropriate downshift(s), when the operator uses full throttle. A kickdown switch provides an electrical signal to the TCM when the accelerator pedal is fully pressed. The switch is normally open, connected to vehicle ground. Should the switch fail the TCM will detect kickdown using the accelerator pedal position.

Throttle Pedal Stop (where fitted)
This component, used where the kickdown switch is not fitted, limits throttle pedal travel .in the same way. The kickdown feature is retained, but is controlled by throttle position only. The pedal stop must be set, using the PDU, in the same way as the kickdown switch to optimize performance.

 

The electrical manual says that 5-speed cars (4.0) do indeed have a kickdown switch (but not where its located)

6-speed cars (4.2) do not have a kickdown switch

the 5-speed transmission is really a 4-speed adapted, whereas the 6-speed is a start-from-fresh transmission

 

As far as I can see on the electrical diagrams, only the 4.0 XKR with Merc box has the KD Switch.

 

From the 1997 diagram (not s/c)

 

Serves me right for assuming all years the same after checking only MY99!

Mea culpa.

 

Well its a new one for me! I didn't think the X100 had a "kickdown" switch and yet I have an early 4.0 R with the Merc box. I don't for a minute beleive the poster who says the 5 speed box is not a proper 5 speed, I think he has made my mistake and is thinking of the S type which used an old Ford box on the 4.0 which is a four speed plus overdrive rather than the ZF five speed in the X100. All X100 are fly by wire so I'm puzzled why they would need a switch at all as this can be easily read from the potentiometer used to control the throttle. As the early throttle bodies are different it may be the source of said switch which is removed in later models.

To answer the OPs question whilst the throttlebody is fly by wire the X100 still uses a wire from the pedal to the potentiometer, it is far from unusual for this to stretch so you are not getting WOT (wide open throttle) There is a good video on u-tube showwing how to check for full throttle opening by adjusting the cable, you need a new cable tie too Worked for my car and is the most common reason kickdown is late to actuate.

 

Thanks for this info P700DEE, I appreciate it.
I’ll dig out the YouTube vid and press on with that. I have a button coming next week and will fit it and see what happens. Worst outcome will be hiding the metal stud currently poking through my carpet.

 

Just to update, got hold of the correct kickdown button and found two electrical connectors underneath and inside the button. Checked under my carpet again and no sign of any, so it’s pushed onto the threaded stud and looking like it belongs at least.
Adjusted the throttle cable today too. It was quite ‘floppy’ I’d say and adjusted it as much as I could without the engine racing when turned on. Adjusted towards the front of the engine it still pretty much the same though and not really any noticeable difference when driving. Is there something I’m doing wrong?
Anyhoo, all in all, plant my foot down hard and it still goes well, but just a lot more engine noise than my last one and can’t hear the exhaust tone above the engine noise (which was the real pleasure of kicking down the last one).

 

So to me that confirms that it is not possible to retrofit a kickdown button to the earlier models which didnt come equipped with one. (I also have the door stop plastic cap on stud)

But what I don't get is what's the purpose of the KD button since there is also a throttle position sensor anyway?

 

Wish you lived closer. I would take you for a drive in mine. It really makes a very noticeable difference when you hit the kickdown. Just ask anyone who has driven in my car. If you have to think if its made a difference it hasn't. You do notice the difference. The commonly used word by my passengers when I use kick down is a four letter word starting in S ending in T and usually in a loud voice.

Have you opened up your air filter box in your car to see if you have the extra air flap in there that opens up at around 3000 rpm?

 

To save you scratching your head wondering what I am on about have a read Click Me To Read

 

As previously posted, I rummaged around under the carpet behind the accelerator pedal to find no sign of any wiring, so the kickdown button I purchased simply covers the threaded metal stud that pokes through the carpet.
So, as before, I do get a surge of acceleration when booting it, but nothing like my previous 2001 XK8 4.0 and assume mine wasn’t fitted with the button with a wired connection and simply has a missing stop. I’ll be having a look at the extra air flap you mention Frank.

 

As previously posted, I rummaged around under the carpet behind the accelerator pedal to find no sign of any wiring, so the kickdown button I purchased simply covers the threaded metal stud that pokes through the carpet.
So, as before, I do get a surge of acceleration when booting it, but nothing like my previous 2001 XK8 4.0 and assume mine wasn't fitted with the button with a wired connection and simply has a missing stop. I'll be having a look at the extra air flap you mention Frank.

Good luck. Hope you have it, the kickdown that is. Whilst your looking for your 'extra flap' you may want to change your air filter too whilst its handy. 8)

 

Thanks Frank, I dont have the extra air flap in the air box.
I was initially asking because I finally got the "crank but wont start" problem for the first time (since 3y I had the car)! And been reading a lot of posts.
I suspect a bore wash issue. Came back from a long trip all fine, two weeks later try to start cranked a bit but battery was not healthy and died, charged it a day and still no improvement, so it may have washed out the cyl on that first try.
Without the kickdown button, I dont really know if by simple pressing the throttle pedal fully is also doing the no fuel trick so I had to remove the spark plugs, I found out they were Bosh (not original NKG) but also the gaps were all between 0.97 to1.1mm which is lower than what the care handbook recommends (1.3mm unleaded fuel).
I cranked it (2x15sec) plugs out and fuel relay out to turn and lube the cyl as suggested, then put it all back together, tried again like 4x 15sec but not improvement. Should I try and push more?
Ive ordered one of these inline spark plug tester but should I change all the plugs anyway?
I already checked the fuel pump is working and I am getting the correct ~40psi of pressure on cranking.
Sorry to hijack this thread!

 

Dont forget to check the main earth connections. Mine drove fine until I reached some roadworks. Like a twit I turned the engine off and there the car stood for 3 days till I got it lifted to my garage.

 

Here is what happened to me........... https://www.jaguarforum.com/showthread.php?t=75123&p=1064865&viewfull=1#post1064865

A non start problem.

 

Just wanted to give an update as I sorted out my problem.
Bought a compression test kit (they're cheap <£20) to assess the cylinders and initially got very poor results (after ~2months not running). cylinders were properly dry indeed because I then added some oil on top and the numbers all went up (but still had some cylinder not doing great which was concerning). I used a juice baster to inject about a tea spoon of engine oil in each, would advise to use a syringe instead you'll make a bit less of a mess. But anyway this extra oil added did make a massive difference as I could feel the engine almost going on first crank, so tried some more and it finally started with a big white cloud! Kept the revs mid high for 30sec and then it was back to idling perfect like before.
One week later, after taking the car for a quick drive to warm up the engine, I redid the compression test and this time all cylinders were reading 170-175psi (TWO and warm engine) therefore Im glad to confirm that my cylinders are all healthy! I think the poorly performing cyl even on wet test were the first ones I checked and the values were improving for the other ones as they had seen more cycles by the time they got tested I think. But so another example that Nikasil engines can still be fine now.

Bottom line is yes if you wash out the cylinders, it can be very difficult to restart the car! (holding the pedal down/shutting off fuel didnt work for me, had to add oil on top of cylinders to restore lubrication and compression.)