Hi all,

I am a happy owner of an XK 4.2 x150.
While I'm generally very happy with the driving experience, I have noticed that when I fully press the throttle in Drive mode, there is a 1 second waiting before the car starts to accelerate.
I'm not sure why this is happening, although I could imagine it's a safety measure, given the amount of acceleration which follows!

My questions are:
1. Can anyone confirm this is the normal behaviour of the automatic D mode?
2. Has anyone thought of and/or tried to modify the response, making it slightly quicker? I imagine that might be quite complicated though...

Thanks a lot in advance!

 

Mine does it sometimes. Seems the engine and trans fight deciding what to do and I wait for the trans to downshift. Usually when I'm just loping along and it's about time to up shift and I nail it that it'll act up. Other times just blip the throttle and it downshifts and is gone. Blaming it on the ghost of Lucas.

You can train the car to react quicker by driving it more aggressively. It will adapt to your driving habits and down shift earlier in the throttle application vs. lug like it does when pap pap drives.

 

I was told that from a standstill, when the car is in either D or S mode, the transmission actually starts in 2nd gear - and that to start in 1st gear - you have to activate the paddle shifter and manually shift the transmission with the paddle out of 2nd gear and into 1st gear. Is that right or wrong? Thanks.

 

Not true in all situations.

If in sport manual mode, it won't automatically downshift to 1st but will start from second unless you downshift to first.

In drive, there can be a small amount of time from when you come to a stop to when it shifts to first.

When not in manual mode, as you come to a stop it likely is in second, but once at a stop it goes to first.

Because it makes the shift to first with the lowest RPM difference, you don't feel it that much.

 

Do you mean a period before it downshifts to a lower gear?

Because of how I drove with the paddles, my car is reluctant to downshift when I hit the go pedal. I wish I could have a peppier program in drive all the time instead of the "adaptive" program I get.

Do you still get this delay in sport mode?

 

Have a look at fuel trims in case it's having a bit of trouble figuring out what's what.

 

Is D mode you refer to "Drive" or "Dynamic mode"? For me, in regular old default Drive mode, there is a short delay when I step on the gas when stopped. In Dynamic mode, there is no delay.

 

His 4.2 XK shouldn't have a dynamic mode.

 

I roll into the throttle to keep it from spinning so I don't think I've ever felt the car downshift to first.

Rode the bike to work yesterday, 43` or so and this morning just about rear ended a car in the slow lane as I was getting on the interstate because this thing accelerated so quickly. Car always starts in 2nd unless I put it in first. Even in sport I need to paddle shift it down to first. If not and I paddle shift up (once moving) it goes to 3rd, not 2nd.

 

Maybe you'd best check on this, doesn't seem right to me. Watch your Tachometer closely while you accelerate from a dead stop while in Drive, I'm pretty sure you'll see five upshifts. Mine does, always has, regardless of how much I mash the skinny.
There's even a video in this forum of someone doing exactly this at a moderate acceleration, and there are five upshifts.

 

Nope. Four up shifts and then the converter locks dropping the last 400 or so RPM. Cold, cold mornings the converter won't lock up until the engine / trans is up to temp. Same as the kids Jag based Lincoln LS except his is only a 5 speed.

 

You have a weird car, sir.
I found that old post:
https://www.jaguarforums.com/forum/x...r-stop-144987/

 

If you use the paddles then it will start in second if you have come to a halt in manual mode without changing down yourself. In all other modes it drops in to 1st when you come to a halt.

The only way you can really tell is to use SDD to monitor which gear you are in. I did that on both my old '07 XKR and current '10 XKR so can 100% confirm that is the case, at least on those two cars anyway.

 

Yep, weird. In drive it always starts from a stop in 2nd. Might be broke but in 1st it makes it almost half way through an intersection before needing shifted to 2nd. I'll check it again this evening on the way home.

 

Never mind, car isn't the weird one...

 

Ranch... HOW old are you???

 

 

I think most anyone that chooses to buy one of these rare cars is a weird one.

 

46, old enough to know I'm not as good as I once was...

 

Mine appears to start out in 2nd as well, based on the display. Whether it does or not I don't know. I have never counted the shifts.