XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Idles too fast-1996 4.0

Thread Tools
 
Search this Thread
 
Old Sep 5, 2014 | 05:41 PM
  #1  
RagJag's Avatar
Thread Starter
|
Senior Member
Joined: May 2012
Posts: 798
Likes: 100
From: Richmond, VA
Default Idles too fast-1996 4.0

My idle has increased from 600 to 750 RPM in drive. Is this an indication of a defective Throttle Position Sensor. These are over $400 on E-Bay. Do any of you know if this sensor causes this. My CPS and Idle Air valve are new. Amazing that the sensor for the 4.0 is so expensive as compared to other TPS on cars. Any advice would be helpful
RagJag
 
Reply
Old Sep 5, 2014 | 06:45 PM
  #2  
ptjs1's Avatar
Veteran Member
10 Year Member
Liked
Loved
Community Favorite
Joined: Apr 2014
Posts: 4,573
Likes: 3,519
From: Kent, UK
Default

Ragjag,

My first thought would be to look for a carbon coating buildup on the throttle body which is keeping the butterfly slightly open thus raising the idle. Try cleaning it gently.

Next thought is an air leak somewhere on the inlet side. Go around with a spray and check every possible joint area whilst the engine is running.

Just to let you know, a new throttle potentiometer (JLM12074) from Jaguar is £141 so not sure why people would ask $400 on ebay.

Good luck

Paul
 
Reply
Old Sep 6, 2014 | 06:25 AM
  #3  
jeffriescr's Avatar
Member
10 Year Member
Liked
Joined: Jul 2012
Posts: 31
Likes: 5
From: Cary NC
Default

Originally Posted by RagJag
My idle has increased from 600 to 750 RPM in drive. Is this an indication of a defective Throttle Position Sensor. These are over $400 on E-Bay. Do any of you know if this sensor causes this. My CPS and Idle Air valve are new. Amazing that the sensor for the 4.0 is so expensive as compared to other TPS on cars. Any advice would be helpful
RagJag




I just bought one from Jaguar classic parts (Heritage) last month, with exchange rate and shipping it came to $155.26




Craig.
 
Reply
Old Sep 6, 2014 | 06:56 AM
  #4  
Japthug's Avatar
Senior Member
Joined: Jan 2011
Posts: 424
Likes: 212
From: Japan
Default

When the TPS dies the idle goes up to 1200-1500, so this is not the case.
+1 on Paul's post.
 
Reply
Old Sep 6, 2014 | 07:13 AM
  #5  
Vee's Avatar
Vee
Veteran Member
15 Year Member
Liked
Loved
Community Favorite
Joined: May 2010
Posts: 5,340
Likes: 1,746
From: Arlington, VA
Default

1. Clean throttle body

2. Perform a manual idle speed reset. (Check forum, I know the steps we're posted, I think I may have posted it!)

3. Take car to dealer to reset adaptations. should cost you $150.

One of those three steps should resolve your problem.
 
Reply
Old Sep 6, 2014 | 09:01 AM
  #6  
RagJag's Avatar
Thread Starter
|
Senior Member
Joined: May 2012
Posts: 798
Likes: 100
From: Richmond, VA
Default

Ptjs1, Several on E-Bay were $500-600.
RagJag
 
Reply
Old Sep 6, 2014 | 10:17 AM
  #7  
ptjs1's Avatar
Veteran Member
10 Year Member
Liked
Loved
Community Favorite
Joined: Apr 2014
Posts: 4,573
Likes: 3,519
From: Kent, UK
Default

Ragjag,

I think that probably goes to show that there are people on ebay just trying it on. £141 new from Jaguar, so no excuse for people charging $500.

Good luck with sorting it.

Paul
 
Reply
Old Sep 6, 2014 | 11:21 AM
  #8  
RagJag's Avatar
Thread Starter
|
Senior Member
Joined: May 2012
Posts: 798
Likes: 100
From: Richmond, VA
Default

ptjs1, ordered the part from Heritage. Cost about $200 with the higher exchange rate.Still less than half the E-Bay prices. This may not be the problem but the one in there now is 18 years old.
RagJag
 

Last edited by RagJag; Sep 6, 2014 at 11:23 AM. Reason: Add to message.
Reply
Old Sep 7, 2014 | 09:25 AM
  #9  
RagJag's Avatar
Thread Starter
|
Senior Member
Joined: May 2012
Posts: 798
Likes: 100
From: Richmond, VA
Default

Vee, there are no dealers in Richmond that work on the XJS. 14 years old is the cutoff.
RagJag
 
Reply
Old Sep 7, 2014 | 02:53 PM
  #10  
Vee's Avatar
Vee
Veteran Member
15 Year Member
Liked
Loved
Community Favorite
Joined: May 2010
Posts: 5,340
Likes: 1,746
From: Arlington, VA
Default

You may consider taking a ride up to Springfield, VA. There's a Jag shop with a working PDU!


Originally Posted by RagJag
Vee, there are no dealers in Richmond that work on the XJS. 14 years old is the cutoff.
RagJag
 
Reply
Old Sep 8, 2014 | 08:21 AM
  #11  
RagJag's Avatar
Thread Starter
|
Senior Member
Joined: May 2012
Posts: 798
Likes: 100
From: Richmond, VA
Default

Thanks, Vee. I will consider doing that if I can't solve the problem myself.
I have heard of that shop before.
RagJag
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
aode06
XK8 / XKR ( X100 )
43
Jul 28, 2023 02:26 PM
workworkwork
XJS ( X27 )
46
Oct 23, 2015 10:26 AM
tomkilner
XJ XJ6 / XJR6 ( X300 )
16
Oct 9, 2015 07:10 AM
Spazzzzzzzzzy
XJ40 ( XJ81 )
7
Oct 5, 2015 04:05 PM
inactualis
XJ XJ8 / XJR ( X308 )
7
Oct 2, 2015 11:13 AM

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



All times are GMT -5. The time now is 10:00 PM.