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First, I wanted to say how informative and helpful this forum is so thank you all!
I recently purchased a 2015 XF Sport 3.0 Supercharged (gas). I finally got around to plugging my scan tool into it and I found that the long term fuel trims in both banks are very high at idle (+18). I know from tuning domestics (U.S.) that this is not good, and usually indicative of a vacuum leak. There have been no warning lights, and no pending DTC on my scan tool yet. I tested around the engine bay with soapy water and propane with no results. Can someone clue me in as to where I should be looking? It seems to me that if both banks are high that the leak should be somewhere in the intake track before the throttle body, but I'm very new to Jaguar engineering so maybe I'm missing something?
Not sure about vacuum leak location, you have to determine that empirically. The plastic air intake cracks easily as it ages. I had to replace mine on my 2010 XJ last year. It had a small crack near the throttle body.
Not sure about vacuum leak location, you have to determine that empirically. The plastic air intake cracks easily as it ages. I had to replace mine on my 2010 XJ last year. It had a small crack near the throttle body.
Did you already clean your MAFs?
Sorry for the very late reply. I did find the plastic part around the throttle body deteriorated. It essentially fell apart when I removed it from the throttle body. New intake has been ordered.
Sorry for the very late reply. I did find the plastic part around the throttle body deteriorated. It essentially fell apart when I removed it from the throttle body. New intake has been ordered.
Thank you!
Hi, my car is having this same issue, and I can’t seem to find a vacuum leak, did you ever find out this issue with your car? Thank you
The plastic air inlet duct, (The plastic piece around the throttle body,) which has a stainless steel clamp ring (jubilee clip) which clamps the air duct to the throttle body has a tendency to absorb heat from the water pump directly below, and cook this plastic collar duct fitting to the metal throttle body. Resulting in the degradation, (breakdown) of this plastic collar which on break down allows excess air into the engine.
While the inlet throat, has a bitumen and alloy heat resistant collar above the water pump, the clamping ring to the throttle body, does not. Hence the overheating, and break down of the air inlet duct where it attaches to the throttle body due to over heating.
A little wordy, but the original statement was not that clear to me.
You just got to know Ali express, makes them for a reason!
Vacuum Leak
