XJ40 ( XJ81 ) 1986 - 1994

High Idle

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  #21  
Old 05-30-2017 | 04:23 PM
Joel Moross's Avatar
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From: ashcroft, BC
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Could my idle problem relate to a problem with the intake air temp sensor??

The car has a ff4, rich mixture problem
Poor driving performance
intermitent ping.
higher than normal idle.
 

Last edited by Joel Moross; 05-31-2017 at 03:57 AM.
  #22  
Old 05-30-2017 | 10:29 PM
Don B's Avatar
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From: Crossroads of America
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Originally Posted by Joel Moross
Could my idle problem relate to a problem with the intake air temp sensor??

The car has a ff4, rich mixture problem
Poor driving performance
intermitent ping.
higher than normal idle.

I guess the short answer is yes, the IATS could affect idle. At least on the 4.0L cars the IATS is a secondary input for correcting ignition timing but it is not directly involved in fueling. It's possible that if your IATS were stuck at a high resistance or was shorted the ECM could think the ambient temperature is extremely cold and as a result might apply an inappropriate timing strategy.

I don't know how different the engine management system is for the 3.6L cars, but you might find some clues in the 4.0L EMS Diagnostic Manual, which you can download here:

AJ6 4.0L Engine Management System Diagnostic Manual / OBDI


Also, another friendly reminder to please add the year, model and engine information of your car to your signature line. I had to go back to post #14 to be reminded. Some folks won't bother.

Cheers,

Don
 

Last edited by Don B; 05-30-2017 at 10:32 PM.
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  #23  
Old 06-01-2017 | 07:54 PM
Joel Moross's Avatar
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From: ashcroft, BC
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Today I did make some positive progress.

I disconnected the IAT sensor and in place connected a resistor.

Started the car and she sputtered and the idle droped off and came back to 800rpm.

So now the idle is approximately whete it should be. A bit of a shake but an improvement for sure

IAT is on order.


The engine.managment manual, is there such a thing for the 3.6l??
 
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  #24  
Old 06-02-2017 | 12:46 AM
Don B's Avatar
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From: Crossroads of America
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Originally Posted by Joel Moross
The engine.managment manual, is there such a thing for the 3.6l??
If there is, I don't recall finding it as a free pdf download anywhere online, but it may be on one of the DVDs available from the Jaguar Daimler Heritage Trust (jaguarheritage.com). I'm away from home so I can't check the DVDs.

But the principles of operation of the Engine Management System should be virtually identical between the 3.6L and 4.0L cars so the manual I linked to earlier should be relevant to your engine.

Cheers,

Don
 
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  #25  
Old 06-09-2017 | 08:32 PM
Joel Moross's Avatar
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From: ashcroft, BC
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Big improvment today!

turns out a huge part of the problem was my brand new Taylor Spryo 8mm ignition wires.

could not hear them arching and had no reson to think they had a proble but, in the dark that was a whole diffrent story. There was spark crawling all over the from the wiress Not ionization. Thought maybe a bad ground so i used my jumper cable from the block to the battery negitive terminal with no change

changed the wires out the univeraal MSD.

My fuel fail 4 is gone.
Idle no longer hunts around on cold start.
Tonight i am going to try and get the idle set correctly.


Cheers!
 
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  #26  
Old 06-11-2017 | 01:28 AM
Joel Moross's Avatar
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From: ashcroft, BC
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[QUOTE=XJSolver;


-set TPS to 0.6 volts at closed throttle
-set throttle butterfly to 0.05mm or 0.002"



[/QUOTE]


When Setting The butterfly Clearance to .002,
What is the .002 in reference to?

Is this the clearance between the butterfly and the wall of the Throttle body?

 
  #27  
Old 06-11-2017 | 10:57 AM
Lawrence's Avatar
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From: Victoria BC Canada
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Is this the clearance between the butterfly and the wall of the Throttle body?
Yes. Put the feeler gauge between the bottom of the butterfly and the throttle body.

Larry
 
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