Jaguar S-Type 2007 2.7D.
Silly question it may sound, when pulling away is it normal for the car accelerator pedal to have some play (around 1 inch) before the car starts to move, (hope I'm explaining my self).
Noticed that this is not the case compared to the petrol V6 model.

Just thought I'd ask being a newbie with the S-Type

 

You may want to make your enquiry on the UK/Eire forum as most member of these forums are from North America where JLR never sold a diesel variant of the X200/X202.

 

One quick thought:

Try revving the engine with the transmission in neutral or park. Do you still get the apparent lag, or does the engine respond right away now? Was thinking perhaps the issue is with the transmission, not the accelerator pedal.

 

Hi Karl, it more about pressing the pedal to move away, there is about an inch of play before the car starts to move, I know there is some level of play on accelerator pedals but didn't think it would be this much, car does run well though.

 

If it's like the petrols (i.e. all other S-Types), it's "drive by wire" i.e. the accel pedal does not in itself control the throttle etc. Instead, it is read by the PCM (via redundant sensors) and the PCM decides what to do (add fuel or whatever).

On those cars a fault in the accel mechanism's sensor(s) triggers a code (and limp home or the like) and I expect it would on the diesel.

On your car I'm doubtful it can be adjusted but do not know for sure.

You would NOT be adjusting the throttle, of course, bearing in mind how it's all designed.

Now, on the petrols something like an air leak can mess with response (because it means the PCM is not fully in control). No idea on the diesel.

 

I think I'll live with it as its not making driving the car difficult etc, really appreciate your reply to my "help", thank you.

 

Gotcha, there's a lag when you first drive off. Unfortunately, you never quite answered the question. What happens when you rev the engine in neutral or park? Not trying to bust your butt. I'm just trying to get an idea of the exact nature of the problem. I see several possibilities:

1) Is this an input signal problem? Maybe the pedal is feeding inaccurate position data to the computer. This isn't very likely, unless you're getting a fault code. The position sensor has two channels that are constantly compared to each other.

2) Maybe this is as simple as the pedal is physically loose, or the sensor is loose relative to the pedal. I've never had one apart, so I've no idea how things are physically arranged. Just thinking out loud.

3) Maybe this quirk is exclusive to the diesel model. All of us are at a disadvantage because there are very few diesel owners on the forum. Maybe it has something to do with the engine's torque characteristics, and the computer deliberately lets the engine RPM increase slightly from a standing stop for better driveability. Do you have a standard or automatic transmission? This would only make sense with an automatic, of course. Once again, just guessing

So that's why I'm asking what happens when you rev the engine in neutral. This would help narrow down what is happening.

Do you have access to a scanner? It would be very helpful to watch live data for "throttle position" as you cycle the pedal. Also, please check for any fault codes.

 

My old S-type diesel used to have a little play in the throttle before picking up. There's also a flat spot right off idle on the standard map, which I understand was for emissions purposes.