XJS V12 Runs then stops
Discussion
As well as the aforementioned, it would also be worth checking the water temp sensor - they are a known trouble spot and can give your intermittent fault until they finally give up altogether. Negative temp coefficient type which have reducing resistance as temp rises. If you have one available or can scrounge one, a 2.2 k resistor pushed between the terminals on the disconnected connector will get you going without the fault. If that cures it then a new sender is easy to fit to a cold engine and the little bit of coolant you lose is insignificant if you are quick to change it.
Ian
Ian
Thank You Gentlemen
It seems as though it might be the temp sender. Passenger side water rail furthest forward. There seems to be hundreds of sensors on the rails but I believe this is the one that sends signals to the ECU?
I've changed it and all seems well but it seems too easy
Is there an XJS specific forum?
Many Thanks
It seems as though it might be the temp sender. Passenger side water rail furthest forward. There seems to be hundreds of sensors on the rails but I believe this is the one that sends signals to the ECU?
I've changed it and all seems well but it seems too easy
Is there an XJS specific forum?
Many Thanks
There is a lot of info on the Jag Enthusiasts Club web site.and a section for XJS. You don't have to be a member to search but obviously you will to post. Does yours have marelli electrics? - I can't remember when the changeover was.
Hope your recent fix stays put.
Ian
Forgot to say that yes, there is one water temp sensor which sends a signal to the ECU and if it falls outside the design resistance it thinks there is an overheat condition and then the fuelling is cut off - not a nice feeling in the outside lane of the M6! This was before the architecture was improved to include a substitute value for 'limp home'
Roger Bywater at AJ6 Engineering has immense knowledge of these these cars (he developed much of the electronics on these cars whe he was at Jaguar) He has written a very useful book on all aspects of Injection/ignition by microprocessor- worth every penny as these cars start to age and garages seem only able to fix faults by throwing expensive parts at them and still often not finding the exact fault.
Hope your recent fix stays put.
Ian
Forgot to say that yes, there is one water temp sensor which sends a signal to the ECU and if it falls outside the design resistance it thinks there is an overheat condition and then the fuelling is cut off - not a nice feeling in the outside lane of the M6! This was before the architecture was improved to include a substitute value for 'limp home'
Roger Bywater at AJ6 Engineering has immense knowledge of these these cars (he developed much of the electronics on these cars whe he was at Jaguar) He has written a very useful book on all aspects of Injection/ignition by microprocessor- worth every penny as these cars start to age and garages seem only able to fix faults by throwing expensive parts at them and still often not finding the exact fault.
Edited by Orcadian on Friday 22 April 08:18
Edited by Orcadian on Friday 22 April 08:20
Orcadian said:
There is a lot of info on the Jag Enthusiasts Club web site.and a section for XJS. You don't have to be a member to search but obviously you will to post. Does yours have marelli electrics? - I can't remember when the changeover was.
Hope your recent fix stays put.
Ian
Forgot to say that yes, there is one water temp sensor which sends a signal to the ECU and if it falls outside the design resistance it thinks there is an overheat condition and then the fuelling is cut off - not a nice feeling in the outside lane of the M6! This was before the architecture was improved to include a substitute value for 'limp home'
Roger Bywater at AJ6 Engineering has immense knowledge of these these cars (he developed much of the electronics on these cars whe he was at Jaguar) He has written a very useful book on all aspects of Injection/ignition by microprocessor- worth every penny as these cars start to age and garages seem only able to fix faults by throwing expensive parts at them and still often not finding the exact fault.
Yes it has Marelli. It has two king leads one goes to the Marelli coil? and the other to another unit which sits under it.Hope your recent fix stays put.
Ian
Forgot to say that yes, there is one water temp sensor which sends a signal to the ECU and if it falls outside the design resistance it thinks there is an overheat condition and then the fuelling is cut off - not a nice feeling in the outside lane of the M6! This was before the architecture was improved to include a substitute value for 'limp home'
Roger Bywater at AJ6 Engineering has immense knowledge of these these cars (he developed much of the electronics on these cars whe he was at Jaguar) He has written a very useful book on all aspects of Injection/ignition by microprocessor- worth every penny as these cars start to age and garages seem only able to fix faults by throwing expensive parts at them and still often not finding the exact fault.
Edited by Orcadian on Friday 22 April 08:18
Edited by Orcadian on Friday 22 April 08:20
Useful tip on AJ6 Engineering..Thanks
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