I have a 1996 XK8 which always starts immediately, runs for 3 seconds and then cuts out.
Having already searched for ideas on the forums and also having a perfect running 1996 XJ8 with the same mechanics, I have swopped and tried many parts to see if the problem is solved, with not much success as yet!
The following parts have been swapped from my XJ8 onto my XK8:

fuel pump
fuel pressure regulator
fuel injectors
I have tested fuel pressure at the rail, during running and at rest and it is fine, holds 3 bar
The battery is excellent
Changed both front cam sensors
Changed crank position sensor
Changed spark plugs and coil packs
Changed throttle body
Changed mass air flow meter and lambda's
Checked fuel tank purge system for leaks
Checked vacuum system for leaks

The car will only run if I pour petrol directly onto the butterfly and will continue to run if I do this so I am assuming from this that I have no signal to the fuel injectors.
Can someone advise what to look for next and hopefully a solution?
Thanks

 

I would recommend pulling the connector for the ECU and cleaning the contacts and inspecting for loose or damaged wires. The sequence for this year XK8 is when you turn the key to on the fuel pump runs for 3 to 5 seconds and shuts down. This initial is to charge the rack and is independent of the ecu. Once the engine starts the ECU is supposed to turn on and control the fuel pump. It sounds s though it isn't turning on the pump.

 

xk8v8 - I've moved your post from the General Tech section to the model specific XK8/XKR section where you get a much better response


As this is your first post - stop by the new member section (link posted below) and post an intro - in return you will receive a warm welcome and useful tips to navigate the forum - enjoy!!


https://www.jaguarforums.com/forum/n...-intro-must-5/

 

Thanks avern1 for your reply, also sklimii for moving my post to the correct place!

avern1- I have already cleaned the contacts on the ecu, checked for loose connections and also checked all fuses and relays.

I tried something new today. I removed the 25A starter motor fuse, then held the key constantly in the start position, had another person make contact using the fuse to crank the engine. The moment the engine started the 25A fuse was removed and I held the key constantly in the start position and the engine ran fine. I kept it running for over a minute, it sounded fine and I was able to rev the engine. The moment I released the key to normal run position, the engine stopped.
Can anyone advise me what could be going on from this new information?
Thanks in advance

 

Sounds like it has to be to do with the ignition switch internals / wiring.

 

Another thing to check is the evaporative gas canister. Depending on how it dies. Could your canister be flooded? Or the lines pinched or cracked? Does it die as though it is being starved or cuts out like someone pulled the plug?

 

The ignition switch or the ECU. The first year ECU in US cars suffered from leaking capacitors and it may be true for yours also.

Disconnect the negative battery cable from the battery, touch it to the positive post, then remove the ECU, open it and inspect for damage from leaks.

 

Thank you everyone for your help and suggestions, especially RJ237 who turned out to be correct and my xk8 is now up and running again!
A month ago I decided to send my ECU to the States for testing/repair as no one in the UK could help me.
They ran a series of tests on my ECU and although no problem was found, they cleaned the ECU and replaced six capacitors.
I received it back last week, connected it and it ran perfectly so very, very happy and thankfully an inexpensive fix after all!
Thank goodness I had the spares on my XJ8 to try on the XK8 without having to buy them, otherwise it would have cost a small fortune.

I would like to recommend the company who repaired the ECU.

ECU Repair 1
730 N.Minnie St
IL62292 TILDEN
USA
Their number is 800 737 0915

I was able to discuss the problem I was having with the car with a technician at the Company before sending it to them for repair and he was very helpful and said that he thought it may be the ECU which it did obviously turn out to be.

It is good to be back on the road again!

 

xk8v8...what did they charge you not including the shipping back and forth?

 

'A month ago I decided to send my ECU to the States for testing/repair as no one in the UK could help me.'
? AJ engineering in Cheshire, their advertisement is 8th on the featured sponsor list on the right!!!!

 

The proper name of the company I sent my ECU for repair to in the States is SIA Electronics, ECU Repair 1 is their ebay name.
The repair of the ECU in the USA was $195 not including shipping but they said that they had run a series of tests on the ECU and could not find anything wrong with it so they refunded almost all of the money but just charged a small fee for the testing. It was only when I received the ECU back and the enclosed note said they had cleaned it and replaced some capacitors that I reinstalled the ECU in the car and all was running fine again.
So I assume that for the normal $195 repair fee that it would normally include more comprehensive repairs than just cleaning and replacing capacitors.
I did phone several companies in the UK to ask about sending it for repair there but everyone I phoned said they did not have the equipment for testing an ECU on an XK8 that old. I honestly cannot remember if I contacted AJ engineering or not so cannot comment.