Since you mention that the only variable was the temperature, electrical resistance increases when it is cold and becomes less as temperature increases.


Under hood (bonnet) there are at least 3 sets of ground wires that are prone to corrosion and can cause some of the problems that you have described. One each with 4-5 wires behind each headlight and one set on the firewall behind the throttle body. Each consists of a stud swaged or spot welded to the frame with eyelets secured with an acorn type nut.


Remove the nuts and examine the surface that the eyelets are squeezed between at the frame and the underside of the nut. You may need to clean corrosion off the nut face, stud face or the eyelets themselves with steel wool or a Scotch-Brite pad. Apply some silicone bulb grease on the surfaces before retightening the nuts, etc.


The various computers used throughout these cars are very sensitive to slight increases in resistance that will cause these types of problems.


Check the condition and tightness of the braded ground strap from the engine and transmission to the frame for both tightness and signs of rust.

 

Far more likely iced-up fuel injectors.

 

"electrical resistance increases when it is cold" Actually, not. Battery voltage may drop, but electrical conductance increase for lower temperature for most metals, including all used in a car's conductors.

 

hi Everyone.
Sorry to thread jack, but my father's jaguar is suffering from this exact issue.
I'll explain how it drove in its doing days before she just stopped all together.
The Transmission was very touchy, at a complete stop, she idled nicely, but as soon as you touched the gas or would free Rev and the kick it into gear causing micro burnouts.
One day it would not start at all, no crank just the small "click --- click"
Left it sit for a day, started rough the next day but ran with a rough transmission.
Parked overnight the next morning cranked multiple times, never fired up. Came back 1 hour later, fired up after 6 attempts. Drove it for a bit, very rough motor was struggling.
Since then it hasn't even clicked, it just gives the Roledex of dash warnings, engine failsafe, taillights, abs, transmission... Etc etc.
All the fluids are full and the oil is brand new. Many mechanics have had a go and none of them including jaguar has any coercive answers.
Just seeing if anyone has any ideas

 

That may well not be the trans.

Go with the usual (see many threads) ways forward for a car that has failing battery / no crank / etc (you search based on what doesn't happen).

If it's a 4.0 has it had its chain tensioners (use Search) changed to metal-bodied ones?

 

YEAH- everything you mentioned COULD be a result of a failed battery. Its easy to test, and until you are sure the battery is OK, you are wasting time and money.

 

I need to know what fuses under the hood control the engine start when everything else is working......All power good...guages are good, key good, once before just had to swap two fuses.....which two/??