Hi everyone! New to this forum, hope this is the right place to post this
I just bought a XFR 2010, it just had its gearbox changed before I got it, the paper from the shop says it's a new better one because the old one was known for having issues. However, on idle and on cruise the tachometer is jumping up and down a bit. If i try to hold steady on 2500 rpm it will jump from around 2400-2600 rpm.
No idea if it has something to do with the gearbox change or if it is something totally different, what do you guys think?

 

Could be a air leak or MAF issue. Any check engine lights present or fault codes popping up on the dash?

 

No CEL or anything on the dash. The car is going to my local shop next week to get my cutouts done, maybe I can ask them to check for codes thru the OBD, or is it only Jaguar shops who can do that?
Can it be the MAF sensor but I don't get any codes?
Also, I think the car feels quite "slow", if I do kickdown in first gear the tires doesn't even brake lose, and I have read very much about traction issues with the XFR and XKR, but I can barely get mine to spin.

 

Hope I'm not insulting you, but did you switch the traction control off by holding down the DSC button by the shift knob down for 10 sec? You should see a message on the display between the gauges that says "DSC OFF". If it won't spin them then...Houston, you have a problem.

Does it it surge on flat ground with cruise control engaged?

And curious, why did you buy it if it wasn't working well or without test driving another to know what it should feel like? I had driven my friend's SC the weekend before I test drove mine, so I knew what expectation to have with the XFR. And during the test drive, I thought something might be wrong with the diff. Turns out the diff was bad and it died a month or two later. But it cost me nothing since I had factory warranty for six months with a seven year extended to back me up. And I stole the car, so I was willing to put some time in to get it sorted out.

Not sure if you have a warranty, but I sure hope so if the DSC off doesn't help with the power delivery. And after turning off DSC, don't just mash it unless you're somewhere like a parking lot or you might have some body and suspension issues as well, if you know what I mean

 

Yes I have the traction control fully off, and I can get the wheels to spin, but not without braking at first. If I'm braking and punch it I can do some serious burnouts, but from what I've read you should be able to smoke the tires just from punching it, maybe even in speed about 15mph?
And when it shifts to second gear it's no way the tires would spin. Dont get me wrong the car is not super slow, I just thought it would feel faster. When I test drove it it was raining really bad and there where really no good place for me to punch the throttle, we were in a town. But from what I could feel on the test drive the car was running allright.
The thing is I live in Sweden, there aren't really any XFRs here, so trying another one is hard. My previous car was a tuned BMW 535d with about 750nm and 370hp, it felt just as fast as this car. The only time I think the XFR really feels like it is pushing you back into the seat is in first gear.
But it's a big car, didn't think the rs7 I drove with 720hp felt that fast either. Maybe it's all in my head..

And I have not tried the cruize control, will do tomorrow.

Thank you guys for the quick answers

 

Sorry for bumping, but I think I'm going to try to clean the MAF with crc spray. Is it really necessary to do a hard reset after? I was thinking because I don't got a CEL or anything.
And if it's a airleak, can I spray "start gas" (not sure about the english word for it) at the tubes in the enginebay to detect the leak?

Thanks!

 

If you do that make sure it's non chlorinated. FWIW my recent MAF issue threw a P0101 code but the symptoms sound somewhat similar.

 

I have the MAF sensor in my hand right now, and it actually looks brand new. No dirt what so ever from what I can tell. Almost dissapointed, was hoping cleaning the sensors should do the trick. You think I should spray them anyway or just put then back in?
I was just out driving with my brother, he was driving behind me in his Audi and he said that when I gave full throttle it came a little cloud of black smoke, normal?










EDIT: I just found that one airbox has a crack in it so I can see the filter inside, do you guys think that can be the problem? Is it OK to use glue to fix it or should I buy a new one?

 

Any crack is liable to create weird MAF readings / strange engine behaviour.

 

Just glued it back together and sprayed the sensors with electronic cleaner. Will come back later with results

 

My car puts out a puff of black exhaust too when you hit it really hard. I always assumed it was due to the rich factory tune because my car is in perfect health

 

This may help if you have not found the fault yet..........

had strange running and idle problems with my XFR.......whilst inspecting the vacum pipes i took off the engine cover and pulled off the LH vac pipe that goes from the air intake tube to a small diapraghm pump in the center of the engine........blew down it and could hear the whistle of air!!!! Span the pipe over and voila!!!! It had perrished and had a small slit in it......replaced it with a bit of 6mmID hose i had lying around and the car is running better than ever..........may be worth a look too

 

Did you ever get a check engine light for that leak? It seems like the ECU should be popping a lean condition if it is seeing a leak in the system. It would make it much easier to diagnose these issues.

I have a lopey idle that recently popped up, which I need to track down. I do occasionally get a P050B code. When I clear it it won't come back for quite a while. I'm guessing it's a small vacuum leak. In my case the 4.2L SC has been know to have a vacuum leak back behind the supercharger so I guess I'll start there.

 

Nope.........no EML on the dash.

something else i noticed too was that the tailpipes were sooting up really quickly......so would think its actuslly running rich.
Two days of driving now and absolutely no soot on the pipes!! Still running like a dream..........my advice would be pop pff each hose one end only...... .......give it a blow.....oo er.....and see if you can feel/hear any leaks. Found mine in about 5 mins!!!

 

Just going back to the OPs original post, you said "I just bought a XFR 2010, it just had its gearbox changed before I got it, the paper from the shop says it's a new better one because the old one was known for having issues."

I've not seen anything about gearbox issues on any of the XF models - in fact (I may be wrong) but I don't remember any posts on these boards except for those very early gear control issues on the 2009 that were changed under warranty.
So I might suggest trying to better understand what the gearbox issue was as it sounds suspicious that someone replaced the gearbox 'just in case' then sold the car... Might be worth tracking down a bit more of the history or speaking to the shop that did the work?

 

If there was a air leak creating a lean condition the ECU should detect it and dump more fuel in to compensate. It would run rich so that makes sense.

 

I also have a lopey idle sometimes, but usually only when the engine is hot, and I start it up again after getting some gas or what ever. The other day the engine actually died and I had to press the start button again. On cold starts it's OK 90% of the times.

 

The gearbox was not changed "just in case" -it was broken, it wouldn't shift.
I have the paper from the shop in front of me, I quote (and translate)" This car has a clutch fault. It's internal in the gearbox, the oil in the gearbox is black and smell. The car can't be driven. Can get a used box for 48750kr (6k dollar) BUT these gearboxes are known to be bad and Jaguar has changed them to the gearbox I have in the quotation. / Thomas.

 

I had same issue on my 2009 XF S/C...fixed problem by replacing cracked vacuum hose that connects to fuel pressure regulator . It also fixed P0172 and P0175 codes I was getting .