XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Mystery Vacuum valve

Thread Tools
 
Search this Thread
 
  #1  
Old 03-29-2016, 07:19 AM
scottpeterd's Avatar
Senior Member
Thread Starter
Join Date: Apr 2015
Location: Uganda
Posts: 394
Received 161 Likes on 91 Posts
Default Mystery Vacuum valve

As I'm doing spring cleaning on my new toy (1992 Facelift Convertible), I found two devices that I can't identify.

They are both on the A bank. The first one is firmly mounted on the side of the intake manifold near the front of the engine. The second on is dangling under the pressure accumulator on the brake. I found this when bleeding the brakes.

They are Nippon Denso. #'s written on them are 184600-1120 and EBC 3731.



Any idea what these are?
 
  #2  
Old 03-29-2016, 07:26 AM
Doug's Avatar
Veteran Member
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,743
Received 10,757 Likes on 7,101 Posts
Default

The blue widget is a 'solenoid vacuum valve'

Part no. EBC3731 | Solenoid vacuum valve parts from Jaguar Heritage Parts UK


Cheers
DD
 
  #3  
Old 03-29-2016, 07:32 AM
scottpeterd's Avatar
Senior Member
Thread Starter
Join Date: Apr 2015
Location: Uganda
Posts: 394
Received 161 Likes on 91 Posts
Default

Doug,

Any idea what it is used for? And why would there be two of them on the A bank, rather than one on the A and one on the B?

Cheers
 
  #4  
Old 03-29-2016, 08:59 AM
JayCee's Avatar
Senior Member
Join Date: Nov 2015
Location: Summerville s.c.
Posts: 298
Received 41 Likes on 29 Posts
Default

On my 94, one is near the front of the A bank intake and is for the fuel pressure regulator / hot start system.
The other is under the intake at rear of the A bank and is for the air switching valve, which controls the air pump distribution (emissions).

Sorry... for some reason I am unable to download the pics.

You can download the workshop doc at https://www.jagdocs.com inexpensive and very valuable. It has detailed diagrams of all the vac lines.
 

Last edited by JayCee; 03-29-2016 at 09:33 AM.
  #5  
Old 03-29-2016, 09:18 AM
Join Date: Sep 2012
Location: Denver, CO
Posts: 751
Received 313 Likes on 205 Posts
Default

If I am correct, that valve on a '92 is used to provide vacuum to the cruise control bellows.

Mark
 
  #6  
Old 03-29-2016, 02:11 PM
Eaa's Avatar
Eaa
Eaa is offline
Senior Member
Join Date: Aug 2012
Location: Milwaukee WI USA
Posts: 245
Received 49 Likes on 37 Posts
Default

Originally Posted by Safari
If I am correct, that valve on a '92 is used to provide vacuum to the cruise control bellows.

Mark
on a 91 also, as I recall, at least it looks very similar, found on the forward right side of the engine
 
  #7  
Old 03-30-2016, 04:52 AM
NathanDD6's Avatar
Senior Member
Join Date: Aug 2015
Location: Durban
Posts: 646
Received 52 Likes on 40 Posts
Default

Blue thingy is part of a redundant cruise control device, as a back-up if the primary system fails if I remember correctly, I could be wrong though.
 
  #8  
Old 04-03-2016, 06:36 AM
scottpeterd's Avatar
Senior Member
Thread Starter
Join Date: Apr 2015
Location: Uganda
Posts: 394
Received 161 Likes on 91 Posts
Default

I think JayCee is correct.

I started to get into this because I found the valve dangling by the vacuum lines under the intake manifold.

Of course as soon as I moved it to inspect it, the vacuum lines crumbled, and it wasn't possible to figure out how they were hooked up.

Doug: that pic is invaluable. I've not been able to properly replace the lines.

Thanks to all for the help
 
  #9  
Old 04-03-2016, 07:46 AM
JTsmks's Avatar
Veteran Member
Join Date: Nov 2012
Location: Fleming Island, FL
Posts: 1,756
Received 718 Likes on 552 Posts
Default

Nathan is correct about the cruise control add on. Mine was on the front of the manifold (I removed it, cruise works fine). Not sure about the one under the accumulator . http://www.kwecars.com/technical/v12...ows-explained/
 

Last edited by JTsmks; 04-03-2016 at 07:55 AM.
  #10  
Old 04-03-2016, 08:33 AM
scottpeterd's Avatar
Senior Member
Thread Starter
Join Date: Apr 2015
Location: Uganda
Posts: 394
Received 161 Likes on 91 Posts
Default

Ok, so forward one is part of cruise control. Aft one is part of the air injection system.
 
  #11  
Old 04-03-2016, 08:48 AM
JTsmks's Avatar
Veteran Member
Join Date: Nov 2012
Location: Fleming Island, FL
Posts: 1,756
Received 718 Likes on 552 Posts
Default

That would explain why I didn't have the rear one as my air injection system has been removed.
 
  #12  
Old 04-03-2016, 09:07 AM
JagCad's Avatar
Veteran Member
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 6,796
Received 2,399 Likes on 1,880 Posts
Default

Good place to connect a vacuum guage for diagnostic purposes.


Make sure it is securely plugged, o'wise it is an uneeded vacuum leak..


Carl
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
xjtom
PRIVATE For Sale / Trade or Buy Classifieds
1
03-31-2016 04:16 PM
nick.R
XJS ( X27 )
3
03-26-2016 06:52 AM
MonacoDK
XF and XFR ( X250 )
3
03-25-2016 06:30 PM
garyofnyc
XJS ( X27 )
2
03-25-2016 05:17 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


Quick Reply: Mystery Vacuum valve



All times are GMT -5. The time now is 07:11 PM.