Ok , I'm hoping someone can help me with my latest delema with my 96 xj6.
First it seems that my engine has just failed on me out of nowhere. I went to start it about a week ago and it wouldn't crank. I ended up checking the compression in each cylinder and the all read 50psi or below. I don't know how this happened because the day before it was running fine with no issues.
I have another engine I'm planning to install but here's the second delema.
* The car now will not turn over. The dash lights up and everything but when I turn the key there's nothing. I can jump the starter from under the hood and its working fine. It seems that I'm having some sort of security problem because the door locks have stopped working when I lock or unlock with the key. The gear shifter no longer releases either when the key is turned on and i hit the brake pedal. I've never had a key fob for the car. I noticed that when I open the doors the interior light no longer illuminates as it normally would. Nor does the central lock button do anything when pressed.
I also noticed thst the The red light on the central lock button stays illuminated . No blinking or anything Just constantly illuminated.
I've switched body processors.
I've switched the box in the trunk up by the fuel door.
I've switched the drivers door actuator to no avail..
Before I could hear something in a few of the doors like the door actuators were clicking back and fourth for some reason as well but it has since stopped.

 

A sudden loss of compression is almost certain to be the result of bore wash (search for it). These engines are susceptible to it if started for a very brief time (like moving in to or out of the garage). Easily fixed with a teaspoon of engine oil in each cylinder through the spark plug hole.

But that wouldn't stop the engine cranking. Have you confirmed you have a fully charged battery in good condition?

 

Stupid question, but is your battery FULLY charged? A flattish battery can have the oddest symptoms and you have been giving it a hammering without the alternator kicking anything back.
After that I would be checking Earth points.

Good luck!