I recently purchased a 1995 Jaguar XJ6. It started fine several times but now it just cranks and doesn't start. Here's some things I have done:
1. Overheated; so drained the WATER out & flushed it out until clean, put 50/50 coolant in.
2. Trouble starting, so took off valve cover and gaskets were so bad, oil was covering spark plugs. Replaced gaskets, cleaned spark plugs and coils and put it all together & tried to start it cranks but no start. 2.5 friend says its getting fuel but ignition coils are not firing.
3. Cranks randomely, so drove it 1.5 times around highway exits, started to overheat so made it home ASAP to let it cool, didn't start it up till after thermostat replacement the next day.
4. Replaced the thermostat; old one looked like the original; it was BAD. Put it back together. 5. Tried to start it but only cranks.

Please help!

 

Welcome to the forum DanHill1984,

I've moved your question from XJ6 & XJ12 Series I, II & III to X300 forum. This is the place to post technical questions about your model.

Graham

 

The fuel pump relay will click on for 4 seconds with the key in the on position before the start position . The relay will click offf after this initial fuel priming . The Fuel pump will click a 3rd time back on when the CKPS sees engine rotation > Safty design .

Do you see the tach come alive during starting attemps ?

The ECU need 11.4 volts to operate or you will get nothing but a spinning engine after that point .

A good point is that the engine runs but has a spot of stumble under the bonnet .

There is a thing referred to as a bore wash the be careful of

 

When you took the valve cover off, could you have damaged the wiring loom to the coils at the back of the cover? It can be stressed during coil/cover removal, and your loom will be quite brittle by now. The failure to start after removing the cover seems like a big clue.

 

Make sure the coil connectors are fully on and clicks as they lock on as the seal swells bigger from lubrication .

 

As we understand, sometimes the engine will start as in #3 above when you drove around the freeway off-ramps. Hopefully the new thermostat will cure the overheating problem. Having 50/50 instead of just water in the radiator will be better too!

When you did the engine work, did you disturb the CAMSHAFT sensor? That is the round gray device at the front right of the engine. It can make a big difference between easy and difficult starting. It is mechanically adjustable with a locknut. If it was disturbed (rotated) even a little, it can make starting very difficult (although not impossible after a good long crank). At any rate, it may be worthwhile to reposition (rotate) this sensor a tiny bit at a time, and see if the engine fires any easier. It is a trial and error process, and you should try a few times in either direction of it's original position. But before you loosen it, mark its original position very carefully, in case you discover the no-fire condition is caused by something else.

Make sure the battery is good and try to charge it for a while after your cranking attempts.

If you smell gasoline while cranking, hold down the accelerator pedal to the floor and this will shut off the fuel injectors while it cranks. This will help to avoid flooding and bore wash, and possibly bring the air/fuel ratio into a good zone for firing during that crank attempt.

 

Jaguar X300 Camshaft Position Sensor Repair ~ Jaguar Vanden Plas "The cats meow"