Welcome to the forum David,

I've moved your question from General Tech Help to X308 forum. This is the place to post technical questions about your model.

Looks like you need the Actuator Vacuum Pipe that goes onto the top of the Throttle Body.


(double click on the image to enlarge it)

It's showing as no longer available from Jaguar. Members here with the same model may have suggestions for an alternative.

Graham

 

The hose supplies vacuum to the cruise control actuator (the black cylinder) on the throttle body; it doesn't blow air, it sucks. Your replacement hose is fine (I see it is a vacuum type), you don't need the original. Your problem is probably elsewhere, possibly a faulty vacuum solenoid for the cruise control which applies vacuum to the cruise actuator when it shouldn't so the ECU overrides it. Temporarily, you can disconnect the hose and plug/cap both sides (you will have no cruise control). On my Super V8, the vacuum solenoids for cruise control are under the cover of the vacuum brake booster, next to it (LHD car). On LHD cars, the location of the cruise control solenoids may be different. If not next to the brake booster, they might be under the wheel arch cover. So, you need to follow the vacuum line from the cruise actuator to see where it comes from.

 

Sorry, I meant to say that my car is RHD

 

 

 

 

 

The vacuum line from the throttle body should be attached to a "T" connector feeding two vacuum solenoids on the firewall behind the brake booster (yellow caps).

 

And the vacuum hose from the side of the supercharger goes to the fuel pressure regulator.

 

 

 

If you remove the air intake tube, you can see the fuel pressure regulator (FPR) under the intercooler air temp sensor, at the back end of the right injector rail. See the red line on the picture (the vacuum port is capped); the vacuum hose goes from the FPR port, under the right intercooler and up to the vacuum port you showed on your pictures.

 

 

The free vacuum hose (with a white line) you showed ending near the FPR is part of the vacuum branch for the supercharge bypass valve (connected to the valve by the rubber elbow you showed towards the end of the video, 9 on the diagram); there is "T" (10 on the diagram) on the other side of the elbow; from the T, one shorter hose (11 on the diagram) goes to the vacuum port on the left side of the intake elbow (you also showed) and the longer hose (12 on the diagram), currently ending open at the FPR, should go to the "cross" adapter under the purge valve at the firewall (see second pic). Yo need to pull that hose from under the elbow and bring it to the left side then route it towards the firewall, as shown by the red line on the pic, and connect it to the "cross".

 

 

Your engine runs "strong" because, with the hose currently unconnected, you have no vacuum on the supercharger bypass valve so it is always closed meaning that you have (unnecessarily) full boost all the time. The operation of the bypass valve is such that it will be open at idle and light throttle (high vacuum at intake elbow) reducing the supercharger boost. As you open-up the throttle more, the vacuum in the intake elbow drops and the bypass valve starts closing providing more boost. The more throttle, the more the bypass valve closes (fully closed on high throttle opening - hard acceleration) so it provides variable boost depending on the demand ("power on demand"). It is not recommended to run the supercharger at full boost all the time, like when the vacuum to the bypass valve is disconnected.

 

 

 

David,

I had to Google that to find out whether to BAN you or THANK you.

THANK YOU,
Graham