Anthony. Do you have the tube also. If not i have it new. If need pm me

 

Update...

Swapped out the o ring, plastic clip and the small plastic hose section for the brake booster vacuum. I also swapped out the PCV plastic ribbed hose.

All new parts.

LTFT's (while better) are not where they seem to be. I rechecked all areas today with starter fluid.

No reaction from the brake booster hose (thank God as that was the worst swapping it out) and the PCV hose all good.

When I sprayed near the base of the Throttle Body (which I previously had to remove to gain access to that pesky vacuum port - I didn't disconnect the cooling hoses, just put the TB aside)

the STFT's went full tilt negative.

Is that metal TB gasket a one time use deal?

Also, what is the proper torque for the TB bolts?

If anyone knows off hand - that would be great, otherwise I'll look it up.

Thankfully, I have a spare TB gasket (new) and will swap in tomorrow.

Any other pointers to install it properly would be greatly appreciated.

Thanks

 

I am pretty sure the tb gasket is one time. It has a crush ring that seals when tightened. Crush ring up. Torque i do not know. I also used a light coat of copper spray on the plenum and gasket to be sure

 

Any metal gasket is a one time use. When new they deform to fit. When apart the deformation stays. When reassembled, the gasket re-crushes and deforms in all the wrong places causing gaps. Sounds like you're close to killing the problem.

 

Being careful to put it back on exactly as you took it off.
Reassembling things with the same parts, i have had good luck.

 

Tackled this a few minutes after my post....

Comparing the new TB gasket vs. old, yep - one time deal!

Made sure the gasket was lined up (rib side up) as I placed the TB back in place and ensured the other 3 holes/gasket were lined up with my auto endoscope camera.

I tightened bolts down to 10Nm (same spec as XJ8 - TB bolts) didn't want to over tighten.

Immediate difference.

About 20 mins of city/highway driving the LTFT's are down to 11% bank 1 and 8% bank 2. (From 17/18% and 13%)

First time actually seeing the LTFT's go down since starting this saga.

 

Admins - please re-title to resolved.

I took the car out for a drive.

LTFT's are now at 3.9% both banks.

Please note - metal throttle body gaskets are a one time use item. If you choose to reinstall as I did your rolling the dice.

In my case I came out with "snake eyes". Hoping this post helps others down the road.

Could not find a bolt torque value. Went with 10Nm (same spec as NA 4.2 throttle body bolt torque)

Attached pics are with key on/engine off...

Cheers!

 

Great job Anthony. Bet you have better throttle response too

 

Indeed.

Passed MOT this afternoon with flying colors!!!