XJ40 ( XJ81 ) 1986 - 1994

Rescued XJ40 fuel pump query.

Thread Tools
 
Search this Thread
 
  #1  
Old 10-15-2017, 05:32 AM
jjd's Avatar
jjd
jjd is offline
Senior Member
Thread Starter
Join Date: Oct 2010
Location: ireland
Posts: 290
Received 33 Likes on 28 Posts
Default Rescued XJ40 fuel pump query.

Hello all. I recently saved an xj40 from the crusher. Late 94. Rust free 3.2 high spec. Lovely colour. But deeply neglected. Already unloved these models are dwindling in number so I had to save her. So a repaint and service later and she's safe.

My query is, there was a fuelling issue. No power going to rear blue pump relay. I bypassed this relay to start pump and get car driving. Does fuel pump run constantly in normal course of events? And if so could I run a new live source to relay from switch on dashboard to double as an anti theft measure? Or will I burn out pump shortly? Thanks J. I will post pics soon. She's lovely!
 
  #2  
Old 10-15-2017, 08:22 AM
Join Date: Dec 2009
Location: Wise County,TX
Posts: 11,891
Received 7,878 Likes on 4,762 Posts
Default

The pump needs to run continuously if the engine is running. The relay is disabled if the key is shut OFF or the inertia switch is tripped.

Inertia switch is there to prevent the pump running in case of 'accident' or IMPACT.
You don't want fuel to be fed to a fire in the event of a crash.

This might be the reason the relay has no power??

bob
 
The following 2 users liked this post by motorcarman:
93SB (10-21-2017), Don B (10-15-2017)
  #3  
Old 10-15-2017, 10:08 AM
Join Date: Feb 2014
Location: Crossroads of America
Posts: 19,391
Received 12,736 Likes on 6,379 Posts
Default

Hi jjd,

I'm happy to hear you've saved another XJ40 from the crushers and I'm looking forward to seeing photos!

The fuel pump relay receives its control signal via the Oxygen Sensor Heater Relay, which is mounted on the right bulkhead in the engine compartment. The battery power for the fuel pump relay comes from Fuse C2 (25A) in the fuse box at the base of the right A-pillar. The O2S heater relay receives its battery power from Fuse C4 (10A) in the same fuse box. You might check those fuses, then try swapping in another relay for the O2S Heater Relay to see if the problem is resolved. If the relay is the original blue Hella, they are known to be problematic.

You can download the Electrical Guide here:

Jaguar XJ40 Electrical Guide 1993-1994

Please keep us informed.

Cheers,

Don
 
The following 2 users liked this post by Don B:
93SB (10-21-2017), Lawrence (10-15-2017)
  #4  
Old 10-15-2017, 12:50 PM
jjd's Avatar
jjd
jjd is offline
Senior Member
Thread Starter
Join Date: Oct 2010
Location: ireland
Posts: 290
Received 33 Likes on 28 Posts
Default

Excellent advice as usual. Thanks so much for the help. I'm having difficulty attaching pics from my phone so I'll go on lap top. It really is worth seeing what can be done rather than scrapping these lovely cars.
 
  #5  
Old 10-15-2017, 01:54 PM
jjd's Avatar
jjd
jjd is offline
Senior Member
Thread Starter
Join Date: Oct 2010
Location: ireland
Posts: 290
Received 33 Likes on 28 Posts
Default

few quick pics. as found in march ready to scrap!. during restoration and after. I will get better completed pics up this one taken in hurry as I was very pleased with the result I couldn't wait for better light.
 
Attached Thumbnails Rescued XJ40 fuel pump query.-xj40-b4.jpg   Rescued XJ40 fuel pump query.-20170923_111231.jpg   Rescued XJ40 fuel pump query.-20170923_111208.jpg   Rescued XJ40 fuel pump query.-xj40-during1.jpg   Rescued XJ40 fuel pump query.-20171009_133802.jpg  

Rescued XJ40 fuel pump query.-20171011_162016.jpg   Rescued XJ40 fuel pump query.-xj40-after.jpg  
The following users liked this post:
Don B (10-15-2017)
  #6  
Old 10-15-2017, 01:57 PM
jjd's Avatar
jjd
jjd is offline
Senior Member
Thread Starter
Join Date: Oct 2010
Location: ireland
Posts: 290
Received 33 Likes on 28 Posts
Default

removed the leaper and applied chrome side strips. just my personal taste. flamenco red with oatmeal leather. no rust! really none! 3.2 lovely driver other than fuel pump glitch and shes one of the last xj40s.
 
  #7  
Old 10-17-2017, 09:51 AM
jerry_hoback's Avatar
Veteran Member
Join Date: May 2007
Location: Indiana
Posts: 3,202
Received 1,125 Likes on 790 Posts
Default

Nicely done. Ive tried to buy whole cars from my junkyard but they wont do it. So instead I fill my garage with as many parts as I can get my hands on
 

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



All times are GMT -5. The time now is 02:55 PM.