Questionhi, i have checked and rectified the fan problem but still am gettin the missfiring from cold right through to when its warm, i know the xj's have a independent coil for each plug and the thing i dont know which i would like to check if it has a dizzy cap? or is it all electronic, i am also gona check the ecu connections and the earthing points which i have checked allready but will do again, do you have any other suggetions regarding the miss firing?
thanks
leon
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The text above is a follow-up to ...
-----Question-----
hi,my jag cooling fans are constantly on and runs well once its thoroughly warmed up, but till that time it seems to be missing on firing and lack of power, i have not yet disconnected the fans and checked it thta way, it also stalls and has eratic idling , this is only when this cold weather arrived but was still running like a bag of poo till it was warm. the fans should only cut in when they needed i thought and is there anything i cn check to rectify this problem? when i bought the car the air con belt was not on so i assumed the person b4 me was saving on fuel but not sure, the car is on a P plate and was cheap to buy and only bought it cos of the condition of the car and it was something i wanted to own since a lad.
i would be grateful for any advice.
Merry Xmas and happy new year!!
regards
Leon
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The fans should only come on when the engine reaches a predetermined temperature or, when the AC is switched on. At cold start up they should never be on! Someone may have by passed the switch. The fans being constantly on would cause the car to run cooler longer and perhaps cause the lack of power you describe. That being said,the engine temp is sensed by a water temp sensor, it could be faulty, preventing extra enrichment when cold. One simple thing to check, make sure the cooling system is filled to the correct level.
AnswerHello again; there is no distributor, the coils are fed from a control module. As the fault only occurs when it is cold suggests a mixture problem, not ignition, the most likely cause would be a faulty cold start system, on your car that would be controlled by the water temperature switch. Disconnecting it should kill the engine -letting you know it is working. All sensors provide input to the Engine Control Module, if the signals are being sent then the problem has to be the module its-self. To make sure most mechanics would substitute a known good one to verify, it would be handy if you knew someone with a similiar car? Is the car displaying any fault lights?
