I've been chasing down lean codes on both banks as detailed in this thread: https://www.jaguarforums.com/forum/x...f-hard-257021/, however, to save you reading the whole thread, I'll cut to the chase of where I am now.

Even though I'd addressed the leaking areas from my initial smoke test, it dawned on me that there is probably a 'path of least resistance' phenomena in performing a smoke test, and that maybe I should hook up my smoke tester again to see if plugging those leaks I might discover other leaks that weren't obvious before. I found that there was a leak at the junction of the MAF/Intake Hose and the Throttle Body. There was a TSB about this for early '04 cars. The hose had deformed on the bottom, and the hose clap would not effectively close it. Ordered the part, replaced it, but still no joy though I eliminated another leak. So back to my 'path of least resistance' thesis, would another smoke test reveal the real culprit?

Today I performed another smoke test, and this time smoke appears to be coming from a new location though it is more difficult to see exactly where from, and that's where I could use some help.

Smoke is rising from about where the Throttle Body meets the Intake Manifold. or just below that point but I can't exactly pinpoint it. With the other areas corrected, the volume of smoke is now higher so it makes it difficult to pinpoint. I'm assuming the two places that would be suspect would be the gasket there or the intake manifold gaskets. Is there something else that could explain smoke in that location? Is a failure of any of those gaskets common? Is there something else I should be doing? I see Intake Gaskets listed as "lower" are there "upper" ones as well?

Thanks very much!

 

Nice work so far!

Did you check to see what your fuel trims were before and after the repairs? I agree with the path-of-least-resistance issue. This often leads to feeling like you are playing whack-a-mole, but you are slowly remedying each problem source. I am not sure where your leak is coming from at the moment. Hopefully someone will offer you some good info.

-j

 

When all else fails to resolve your vacuum leak.
Those eight little gaskets, inside of the intake manifold, can cause a hidden vacuum leak.
Not a horrible job, just take your time, &, you will do fine.

 

Update: I've tried, but failed, to see exactly where the smoke is originating from. So I went with the flammable spray while monitoring short term fuel trims method in attempt to narrow it down, with some luck...ish.

STFT is at 25%, which is consistent with a vacuum leak, when I spray it at the throttle body gasket, I get a drop in STFT (down to 10ish%), but when I spray it more directed toward the Bank 1 intake plenum/manifold seam, I get a greater drop in STFT (down to -4.7%). Which would seem to indicate a leak in one of the ring gaskets between the plenum and the manifold. However, like the smoke test, it's difficult to be that precise, it could be the lower gasket...?

I hate to throw parts at a problem without being more certain, but at this point I feeling like if I have to pull the intake manifold (ugh) I should order and replace the eight upper plenum ring gaskets, the two lower intake manifold gaskets and the throttle body gasket. Oh and that weird little hose that runs under the intake while I'm there.

Am I missing something? How hard is it to pull to intake manifold?

 

Printed out the relevant pages of the shop manual, & followed the instructions.
There is some sound deadening material that could get in the way of things on reassembly.