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Matt
Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 21610
Experience:  BEng hons Mech engineering, in auto industry 22 years
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i have a 2005 X Type Jaguar Sovereign 2.0 L Diesel saloon.

Resolved Question:

Hi i have a 2005 X Type Jaguar Sovereign 2.0 L Diesel saloon. She has 170k miles on her and i have owened her for 6 years now. She has never given a ounce of trouble till last week. She has lost power and has gotten smokey, first it was a clear type smoke which then went to black, but stays smokey and has delay in power and also intermittent power when you accelerate. I have changed all the filters and oil in her, but no change. No fault light on dash and nothing shows upo when connected to computor.
Any ideas, could it be suspect Diesel ? would appreciate any help
*****@******.***
Submitted: 2 years ago.
Category: Jaguar
Expert:  Matt replied 2 years ago.

Hello

This could be a lack of fuel pressure from the electrical pump at the tank.

If the connections to this are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,
Ideally measure the pressure at the inlet to the main engine fuel pump and if this is low check the pump as described .

If OK then also check the connections to the EGR valve, if either the vacuum pipe of electrical connection are damaged / corroded then the EGR can be on all time which certainly will hurt performance. Its also possible that its a fault with the EGR valve so its worth removing the valve and cleaning it out with brake cleaner, if it looks particularly clogged then replace it.

If this is OK then check the small vacuum lines to the turbo and its connected control solenoid on the bulkhead, any cracks or leaks can give turbo issues and its best to have the boost pressure measured actually measured with a boost gauge to check that the turbo is healthy and that the sensor is reading correctly

If its a variable vane turbo (they’ll be an actuator on the turbo body - but not a wastegate) then check its vacuum pipework as above and check the connections to the diaphragm / solenoid valve

Also worth checking that the glow-plug relay is switching off as they can stick on and leave the glow plugs also on - on some cars this can force it into limp home

Also worth considering adding a bottle of injector cleaner into the tank as a clogged injector nozzle will reduce power and give poor combustion - the next stage on from this is to remove all the injectors and have them ultrasonically cleaned and flow checked

Also check all the high pressure hoses post turbo/s for any split hoses or cracked metal pipes, also check the ends of the intercooler as its not unheard of to pop the end caps off under high boost
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