As this is my first Jaguar, I'm without a benchmark comparison to see if my power delivery is normal.

I find that most of the torque is being delivered higher up the rev band, and almost seems that there's little low-down grunt.

The car likes to downchange aggressively when going from 30 - 70 mph whilst giving the traction control something to think about, but it's very different to my last V8's in a BMW and Mercedes.

If accelerating gently enough to not warrant a downshift, there doesn't seem to have that 'lazy' V8 smooth pull tht I'm used to.

I like rapid, but lazy progress from my big cars, but this Jag just seems a bit frantic to hustle along.

I probably haven't explained this very well, but does this sound normal?

 

Doesn't sound right. I've the same engine in my STR and it's not like that at all.

Hope some other owners can suggest causes.

 

Assuming that there is nothing wrong with the engine or transmission it could be the cars learned driving program. The car learns and adapts to the drivers driving habits over time. Sine this is a new car to you, you may have a way different driving style than the previous owner. I had a similar issue when I first got my xjr. It would jerk hard from a dead stop. After driving it for a while that issue became less and less. If you want an immediate change you can have your car reflashed. I beleive it's the tcm if I'm not mistaken.

 

Thanks guys. I thought it wasn't right but I'm willing to let the car learn my driving style. I'm having the transmission fluid changed shortly so will look to get the TCM reflashed at the same time to see if that makes a difference.

At the moment the downshifts are quite violent if I accelerate quickly from a modest speed. I'm having to gently feed to throttle in in order to avoid jerky progress. Let's see if it makes any difference.

 

Sounds like its a bit irritating to drive. Mine is a joy to drive and does not behave the way you describe. I have 102,000 miles on it.
Will be interesting to see whether the transmission oil change and the TCM reflash work for you. Good luck.

 

Interestingly, the only place I've found that will perform the TCM reflash is the Jaguar main dealer in Dubai. They charge $245 for it, but say that I have to accept any risk that accompanies the remap.

Will changing the transmission fluid alone make much of a difference?

 

Something that might be worth a try is to disconnect the battery for a short period. I have seen in this forum where this has apparently worked for some people with issues such as yours. This procedure is not supposed to affect the TCM however it does change the fuel adaptation settings.
If you do try this make sure you follow the Jaguar battery disconnect procedure.

 

1st off please share some more photo's of your car!
Never saw a Cranberry interior on an XJ that wasn't black in colour...

Changing the trans fluid without reflashing the TCM or at least clearing and reseting the trans adaptions will probably make the car drive "worse" at least for a while, they should really be done together.

Since you're in Dubai, which is hot/dusty and pretty much a harsh climate on cars, i'd be looking at the service history of the car.

100'000mi / 160'000kms is the normal major service point where everything gets changed out; spark plugs, fuel filter, air filter, supercharger belt, cabin filter, etc... in a harsh climate these should probably be done sooner than the book says...also from the age of the vehicle, it's 10 years old and probably still on it's original sparkplugs...

I would at least have a look at the air filter, might be choked up...

It's been a while since my XJR was stock, but for sure you should feel a shove in your back at low revs, it should move along nicely at less than 1/2 throttle, and without having to kickdown gears just to keep up with traffic...

It does sound like yours isn't quite right, but i'd be looking at the engine performance rather than the gearbox. Sounds like it's being choked somehow...

 

Can't say for certain with your model but for mine yours would be classed as an Arduous market - with services twice as often and spark plugs also changed twice as often (50K not 100K miles for V8).

Unlike ordinary climates, where they say to lave it entirely alone, Jaguar say to clean the throttle plate every service (6 monthly / 5K miles).

Maybe inadequate servicing has been done?

 

Cheers Cambo, I'll definitely get some pics of the interior and post them up here soon.

The car has a full main dealer service history, with only some work on the air suspension having been carried out by an independent.

Got the car earmarked for a major service along with an investigation on a vibration around 50mph under power (not on coast). We figure it's the drive shaft (coupling / bearings or actual shaft) but will see.

Interesting that you say the car will drive 'worse' after changing the fluid without a TCM reflash. ATM the upshifts are perfectly smooth, but the kickdown is noticeably jerky. Do you think without reflashing the TCM this will get even worse, or did you mean something else?

Over here there are a plethora of garages that can look after your Merc or BMW, but Jag owners are left a little short changed. Even the main dealer is reluctant to mess with the software mapping on the tranny.

 

Thy won't be messing with the mapping but they do sound clueless. Maybe the tech who knew about this stuff left or maybe they never had one trained.

 

So just a quick update:

Went to the Jaguar main dealer here in Dubai requesting a TCM reflash and transmission oil change. They said they will do the TCM flash (for $220) but will only change the oil upon my insistence, stating that there would be no comeback if it made things worse (as it goes against their advice).

I've had the fuel and air filters changed as well as a new belt for the SC, but not had the spark plugs changed yet.
Got a pulsing vibration under acceleration which we think may be propshaft related. Not sure if it's the shaft or the coupling but we'll see soon enough.

I'm thinking that I will just get the TCM reflashed and see how that goes and get my indie to do the tranny oil change and flush. I'm going to insist that they use ZF Lifeguard 6, unless I'm mistaken??

 

They sound hopeless - are there no gearbox places? When refilled it must be done properly & with engine running etc and I would not trust a clueless dealer!!

 

Talk to your BMW workshop about the transmission fluid change, several BMW models run the same 6HP26 transmission and they might have experience with the fluid/pan change.

Changing the fluid alone is really a half-job. Changing the pan/filter and the sleeve on the electronic connection, then doing the re-fill is covering everything.

Then you need the Jag/LR SDD diagnostics to do the reflash and reset the adaptations.

Changing the fluid without doing the reflash/adaptations could see the transmission shift worse for a while until it learns on it's own. But it shouldn't hurt it.

 

Yeah the main dealer is pretty poor unless the car is a current model. They simply have no appetite for a Jag more than a few years old.

@Cambo, there's a few good BMW workshops along with an excellent classic car garage than can help with the fluid, pan/filter change. The main dealer is doing the TCM reflash on Tuesday, so I'll whizz it round to the other garage soon after.

 

I recently changed the supercharger fluid (@134K miles), and there is a notable smoothness about the SC engagement now. It's smoother and more powerful. As an added bonus, I went from approx. 17.4 average MPG to 18.6 average MPG. (I have a heavy foot)

Also, try driving the car with the "S" button unlit (This is the sport mode button right above the transmission selector). If you are in Sport mode, it will want to downshift quicker and keep the revs up longer on shifts. If you take it out of sport mode, it becomes more leisurely.

Mark

 

An update on events so far...

So we've isolated the pulsing vibration to be the propshaft coupling. The workshop is saying that this will require a whole new shaft as the coupling is not available on its own.
I read somewhere that the S-Type uses the same parts and the coupling is available to purchase as a stand-alone item. Can anyone shed any light on this at all?

Also, I've had the TCM reflashed which has made a difference, but there is definitely a jolt between 4th and 5th which may signal more serious issues. We shall see I guess.

 

Yes the coupling from the S-Type fits the XJR, change both ends. Same part. I listed the part number once in the XK section, it fits them too.

EDIT here in this thread https://www.jaguarforums.com/forum/x...pshaft-115969/

 

just to clarify, Cambo, does it take two or one of the joints on an XJ8? (I haven't looked at the drive shaft in a long time!)

Here's the jaguar part # from combo's post: C2C12747

looks to be a little over $100-$120 per joint.


*I just hit 100k on my VDP and I'm going to town on her servicing! Considering doing this too...

 

One at each end of the shaft, so two. If one is failing the other can't be too far behind.

I changed mine out as a precaution more than anything else.

This thread https://www.jaguarforums.com/forum/x...85/#post769148 was all the incentive I needed...