So on my XF, I have noticed in the past year I haven't heard the supercharger whine. Also when I go past 3000rpms, I don't feel that the car is pushing or going anywhere. Going 6000rpms is equal to going around 3000rpms I would say. It goes, but it is not the same it just does not push like it is supposed to or used to and plus I don't hear the supercharger whine. it has around 118k miles on it currently.

 

Could your tune have been learned out?

 

Honestly, i feel the tune is still the same, and no codes or anything. No driving problems or shifting problems. It's basically just a performance issue.

 

Is the pulley belt tensioned correctly, i.e; worn belt or tensioner.

 

It is potentially the supercharger actuator (2009-2012). I replaced mine and repositioned it in a way that pre-loaded the piston. Made a world of difference. Heck, pre-loading the piston made all the difference. Learned that from the CTS-V guys. When I bought a new actuator, it came with a gauge that helps.with the pre-loading. The actuator helps keep the supercharger valve closed upon acceleration.

 

 

 

Yes. The install is a little painful. You have to take off the crossover pipe. You can test the functionality beforehand with a vacuum pump. Plenty of online videos on how to test them. Also, the rubber tubing that goes to it becomes very brittle. That might be your problem also.

 

 

I had the same symptoms. It turned out to be the actuator. Most importantly, it must be installed in a position that the piston is preloaded. Watch the video on it. The one I purchased came with a gauge to determine preload. Boost comes in much quicker and stronger now. Prior, it felt like I was running on pure engine.

 

 

I just talked to a good friend of mine that works at the Jaguar dealership, and he said there is no actuator at all for my VIN. He said there is an actuator for the 5.0L but none for mine.

 

Is your car a 5.0L or a 4.2L?

 

it is a 4.2L, 09 XF SC only came with 4.2

 

Ahhhh.... I was assuming it was the 5.0 XFR.

 

Lol no, I even have the info posted in the title. Do you know what it could be though?

 

I'm gonna pluck a random guess out of the air and say the intercooler pump has packed it in...

btw, you should specifically say it's a 4.2L

Because in the calendar year 2009 there were 2010 model year 5.0L S/C models sold.

And there was a 5.0L "Supercharged" with 470HP as well.

Whereas your 4.2L is an "SV8"

And in the UK an "09 plate" XF with a supercharged V8 is a 5.0L

And you cannot expect everyone to read your mind, or your VIN, through telepathy.

 

Oh, i didn't know I thought those were XFR's. Anyways what do you mean by the intercooler pump has packed it in?

 

If the electric water pump in the intercooler circuit stops working, then intake temperatures get very high and the engine ECU pulls back power, a lot.

It's a pretty common thing to go on these cars, especially with age and mileage.

 

I just had the water pump replaced about 2 or so months ago