Im away so not going to get anything done

plan of action on return in a few months.......(prob when everything is even more damp and unloved....its england after all and thought the car is covered its still outside because I cant start it.....so

clean and add earth straps on engine and box

check every battery connection front to back for cleanliness and tightness

new battery

Noticed my transmission module connection (passenger footwell up) was almost hanging off but didnt make any diff when properly plugged back in

will check out the body processor module as suggested....read the symptoms in other threads so it could be

car unlocks and locks as should on the fob so think all my security issues are not part of prob

moral of this story is ....my 82 carbed supercharged mustang can rip the $hit out of the XJR and doesnt have a factory module in its entire body...i can fix anything on it with only a handfull of basic tools and without the aid of a 5 kg workshop manual

I want to love this XJR but i can see its going to be a love hate relationship....too many toys on it to go wrong and 20 times as many ways needed to find out what one or combination of several is the cause

all for comfy seating and the 'waft experience'....Im not so sure its worth the 'I dont have a clue' feeling Im getting....maybe Im just being negative...or positive....its got to be one of the two thats the cause of the problem in this cars electrics

scanners.....codes....i can do that....whats the paperclip trick with this one

got a cold.....depressed....going to bed

 

I have the same problem on my 94 XJR. Have tried disconnecting battery etc. Have also tried tow starting as it is a manual. Any more thoughts anyone? I have two other cars and could swap out body processor module. Engine ECU reluctant to swap as other two cars normally aspirated and both manual...
Thanks Charlie

 

Problem solved. Engine ECU has had water sitting in it. About 0.25" looking at the high tide mark. It was dry when I took it out but.... There are two multi pin connectors, one black and one red. One of the pins on the ECU had corroded/burnt through and broken off ,black plug. I have looped out from the PCB to the wire on the loom above the multi pin plug and it started straight away. I had a clue as the car came with a spare ECU which had failed on exactly the same pin. Reassembled with a light spray of WD40 on the pins/sockets. Water had also been collecting in the recess of the multi pin connector. it may be worth putting drain holes in these recesses to allow any water to drain out. Tip; pull ECU away from the felt pad behind it as this seems to collect moisture. No evidence of water leaks above ECU. I suspect condenstation as it is quite a big lump of metal that is almost isolated from the body shell. All the other ECUs seem to have plastic cases but the Engine ECU has several electronic components clipped to the cast body of the housing.
WARNING one of the PCBs comes away easily when unscrewed the other doesnt due to the clipping mentioned above.
I have also distorted the two covers at the bottom centre to stop water collecting. Also cover distorted at top to allow loop out wire to exit ECU.
Hope this helps...
Charlie