• Advertisement
Xclusively Jaguar
SNG Barratt
David Marks Garages
Make a donation to XJ40.com

some TB TLC.........

Brake buster
Snr Member
Posts: 641
Joined: Sun Jul 03, 2016 8:18 pm

some TB TLC.........

Postby Brake buster » Thu Feb 21, 2019 3:07 pm

the car ran ' fine ' but seemed a little lax on pickup etc, and the next item to be looked at was the condition of the TB and to clean if necessary

removing all the appropriate pipes etc, ( surprised by a pair of coolant pipes going through the bottom of the TB body !!!) i removed the TB , fairly simple to do , and it was indeed dirty inside and out

so some proper carb cleaner and a stiff brush it got a thorough cleaning, it was at this point i noticed that the butterfly closed tight, and not to 2thou as prescribed for the TB

putting it all back together i installed a new gasket, and liquid gasket to the metal mating surfaces of the intake trumpets on the TB , the butterfly was set to 2 thou gap at rest, and the WOT setting was adjusted to make the butterfly sit correctly inside the throat of the TB , a new large O ring was installed on the end of the MAF casting to the airbox, as it was missing,

then the simple ( HA ) matter of getting all the rubber gaiters back on ,

ensuring it was all plumbed back together correctly i turned her over and she sprang to life, let her get to temp but the idle was a little fast, so used the adjuster screw to bring down to just over 700 revs at idle when up to running temp ,

all in all a good job and peace of mind, i can only presume someone had been in there before messing around and messing up all the settings

BB
1994 3.2S in Morocco red and Doeskin/Ruby red interior
1989 V12 XJS White with Mulberry interior
2004 2.1 X-Type Platinum with Champagne Leather interior

previously ,
1999 V8 Sovereign in Seafrost with Oatmeal and Antelope interior

katar83
Posts: 2714
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: some TB TLC.........

Postby katar83 » Thu Feb 21, 2019 3:22 pm

When I did mine there was so much gunk on the butterfly plate and TB that I had to use 2000 grit sandpaper to clean it all up. When you used adjuster screw though you changed that 2 thou gap at rest anyway, should have adjusted/reset tps instead, which should be possible on XJ40 ;)

Also while in there, I would suggest checking TPS operating range(multimeter job on a 40), it should show as close to 5V at WOT as possible. I bet that TB linkage is proper stretched now, after 25 years. Mine was showing somewhere around 4.2V when I checked it first time and adjusting it made a world of difference, like the car got an extra cylinder :lol:
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

katar83
Posts: 2714
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: some TB TLC.........

Postby katar83 » Thu Feb 21, 2019 3:37 pm

PS
TPS should be within 0.57v and 0.62v with butterfly closed and gap set to factory spec. I'd suggest setting it up as close to 0.60V right in the middle of that 0.05V range. Then at WOT as close to 5V as possible(adjust linkage as needed), then reset IACV as per instructions here:

viewtopic.php?f=23&t=6875#p104418

viewtopic.php?t=7448#p119496
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

Walker
Snr Member
Posts: 269
Joined: Fri May 01, 2015 8:10 am
Location: Inverness

Re: some TB TLC.........

Postby Walker » Thu Feb 21, 2019 5:46 pm

I love little gem threads like this, will certainly be checking mine over with a multimeter. It has been cleaned but don't know just how the readings will fare after these years.
Kingfisher Blue '40 1993 3.2S #690760 L399GYP
Sapphire Blue '40 1994 Gold 3.2 #702107 L9CYD
Previous 1994 X300 3.2 Manual