Ok. I've joined this forum to see if anyone knows what the issue here is. It scared the crap out of me.

My 2001 xk8 came back from the garage 3 days ago. I took it for a drive 2 days ago, and it was fine, but very low on fuel. It's parked outside my house on the flat road.
So I got into it, and turned the ignition. I am in park mode.
The engine turned over, at normal idle speed, then after about 3 seconds the engine suddenly revs quite high (x3000rpm) and a screeching noise came from under the bonnet, like a squeeling belt.
The horn started beeping every second, the wipers came on, the air on came on, the emergency lights came on, the headlights came on. Everything is going like the clappers.
Next thing, I see some white smoke coming out from beneath the glove box area on the passenger side, as well as an acrid smell of burning plastic. But this lasted for about 20 seconds, then died away (short circuit somewhere I think).
So I pressed the keys on my fob to turn off the horn - nothing. But turning the key back one notch toward the off position worked to stop the horn.

So as a last resort, I turned the key to the off position to cut the engine. No effect.The engine is still running !
I've got the key in my hand and the engine is still running, and all the lights are on, the wipers still going.

So I get out of the car and stand on the pavement to call the RAC.
3 minutes later, the engine dies due to no petrol. Wipers still going, so I disconnected the battery.
I'm in shock and on a come down from adrenaline.

Any advice most welcome.
Signed
Mr Deparate.

 

Remove and spin test the alternator and check for overvoltage . Replace the voltage regulator while removed and spin test again . Have the battery tested at the same time .

Note: some or all of the power contacts in the king relays may have been welded closed doe to overvoltage and high current .

When powering up the car for the first time have all king relays ( In the red circles ) removed and only put one in at a time do not start the engine and make a list of things that do not work . Remove that king relay and move it to another position and work through that list removing some of the check marks . Continue to recharge the battery with a charger as you work though all the king relays and resolved the foults found by maybe replacing the fuses .

Your Wiring guide for 2001 : See page 23 and look for differences between 98 example and 2001 . See king relays on page 35 . Fuse chart on page 37 .

http://www.jagrepair.com/images/Auto.../jagxk2001.pdf

 

Lady P has great advice, as always. Could you pls tell us what she was in mechanic shop for?

That might help us help you via some dead reckoning the location of the work.

I'm sorry to hear of your trouble. Makes me think what if it happened to one of us. Without a battery switch it's be tough to stop the engine.

The feul pump relays is in trunk. I suppose one could pull relays as fast as possible. Hell, if you are cautious when you next test drive her, ID the relay location. With planned access to it it'll be fast way to shut off an uncontrolled engine.

I suppose the fuel cut off switch by the fuses would be a good contender too. You decide which is fastest access.

John

 

In addition to the advice you have already had, I think I would want to determine what that white smoke was coming from. The Body Processor Module is in that area and one that is having a (literal) meltdown might well cause the faults you saw. I think I would have a look at that before doing anything else (and certainly before reconnecting the battery).

 

The RAC breakdown guy arrived this morning to "diagnose" the car. When I opened the door, and he said "don't bother - I can smell it, I'll send a truck to take it to your garage.".

 

One thing that you did not mention was why it was in the garage the first place.Can't help think that it might have been something that was replaced, worked on, or just mucked up that could have set this chain of events into motion.

 

Hi
Is your car a convertible by any chance?

Member Waldo had a similar 'event' caused by nipped wires in the header rail:
https://www.jaguarforums.com/forum/x...1/#post1529951

 

I'm surprised no one is recommending holy water and a Catholic priest. . That is truly a bizarre set of failure.

 

LOL Sounds like a plan if it doesn't turn out to be the BPM

 

The car was originally in the garage to fix 2 issues and prepare it for mot. The first issue was that it occasionally went into failsafe mode (big issue). The other was that I couldnt get it out of park. (Solenoid issue).
(The failsafe issue was fixed by replacing the throttle body, and the CPU, the solenoid was fixed using a fuse)

Update:
The garage said they traced the problem down to a wire in the ceiling lining above the sun-visor. They said that whoever attached the sun visor, with the self tapping screws managed to catch this wire and pinch it. Over time the wire was worn away and then caused an open circuit. The lack of a signal to the BPM caused the engine to remain on, even when I turned the engine off. The BPM had to be replaced.

Now I agree with the last part, but find it very hard to believe that such a crucial wire would exist anywhere in the ceiling lining near a sun visor. I also find it hard to believe this wire failed in the way it was described.
Especially when the car was stationary and I simply turned it on, so chafing of the wire was unlikely.


Anyway, I'm over a barrel, and have been bled a bit for these issues.
As a token of my appreciation to this group, I thought I should post the results.

 

So yeah, its as MichaelH described here:

Member Waldo had a similar 'event' caused by nipped wires in the header rail:
https://www.jaguarforums.com/forum/x...1/#post1529951

I find it incredible that a wire that is so central to the system is in the header rail, and can be shagged by a sun visor self-tapping screw. Such a poor design.

 

I'm afraid it is so. The sun visor lights are fed from the BPM via this route. The visor retaining screws can pinch the wire causing a short which may not manifest immediately. Usually the fuse blows, but occasionally the BPM is taken out (see Waldo's thread I linked to).

Glad you got it sorted.

edit: wge, we crossed. I'm sorry: you were just one of the unlucky ones. It was an unfortunate routing choice.
edit#2 Just a thought:- the original non-operational park solenoid issue could have been an early symptom as it's the same fuse, IIRC