Well im attempting to get to the throttlebody so i can clean it. Ive read some threads that say a Dirty TB could cause the codes and messages ive been getting.its at about 87k and had been running with a blackened airfilter since atleast 66k (i thought i had changed it but i was thinking of my other car, whoops) How do you get this intake tube off? It looks like its attached to a stud underneath that doesnt look removable. Anyone had the pleasure of doing this proceedure?

 

Never mind that last question lol i got it off. This is the TB completely as i found it, Untampered with. It appears not to be closed all the way.. Idk if thats normal. Ive read that the position sensors are a regular problem so maybe it looks like theres some gunky stuff just out of view so i guess ill clean it

 

Here is some nastyness, i cleaned it up as far as i could reach so that the butterfly valve is clean on the bottom side (the special coating wasnt harmed) and where the valve contacts the body is all cleaned up so hopefully that helps something. Im about to put some high Octane and a bottle of injector/fuel system cleaner in it and keep my fingers crossed. I guess it cant hurt






Toothbush fits just right to hold er open<br/><br/>I broke the handle in half on another one to clean with (it was too tall to move up and down)

 

Just curious, did you paint your intake runner?

 

Nope i probably need to now though. I have always cleaned engines with that stuff from autozone or advanced called Super Clean... Well appearently theyve made it alot stronger and you have to be carefull what you spray it on because now it trys to eatup Paint lol

 

That's odd, my intake runner is the raw aluminum color, not black. I have a 2004 XJR too.

 

I hope I'm not about to burst your bubble Catsgame but your manual indicates that film you removed belongs on the throttle body.

It's common to Ford (who built your Jag). Maybe one of the mechanics can chime in here. I think you want the film on there. Here's the explanation I could find.

"Starting with some 1989 models, Ford introduced a “sludge-tolerant” throttle body and bypass valve design that has a special coating on the
throttle plates and bore, as well as on some bypass valve parts. In addition, all 1993-later vehicles have sludge-tolerant throttle bodies.
This coating must remain in place for correct closed-throttle idle airflow. Any attempt to clean these throttle bodies or bypass valves will damage the coating and alter the idle airflow calibration. These components are identified with a yellow-and-black ATTENTION decal. Do not try to clean throttle components so marked."

There are some "Ford safe" throttle body cleaners on the market that clean the hinge pins but leave the moly in place.

I haven't heard of anyone having problems after removing but the warning is in the Jag manual and I'm posting this so others are informed.

 

Some cars have black intakes, some raw alloy, same for the STR. I believe the very first cars got black, 2003 & very early 2004. Mine is a May 2004 build and has the raw alloy intake.

Not going to comment on the throttle body coating, as I really don't know.

The gunk on the underside of the plate is pretty normal, here's some pictures of mine https://www.jaguarforums.com/forum/x...29/#post954116 that was the original throttle body with around 105'000 miles.

 

Inthink the film or coating survived intact. When i got done it looked like the only thing i removed was the oily black sludge stuff. Input it all back to together and it was idling wierd. I would rev it up and when i let off the rpm would drop back down but stop at 1000 then pause and then slowly drop down to around 5 or 600 (as normal). Ive driven it all day today and now it seems to be back to normal. I dont think anything i did helped anything but help the Bandaide company (everything is sharp under that hood) lol. Anyway the engine feels strong now and smooth. I had the check engine, DSC, Abs, traction control, cruise unavailible, gearbox fault, restricted performance messages starting a few weeks ago and have been trying to eliminate things that could be. autozone scanned and told me a MAF sensor, so i cleaned it to no avail and thats what sent me down this rabbit hole..... Today i checked the ABS wheel speed sensors with a ohms multimeter and found one of them to be bad so i think that should take care of a few of my problems.