Hello


I have an intermittent problem where the car can take 3 or 4 turns of the key to start. I have changed the spark plugs and had it serviced and carbon cleaned. Does anyone have an idea as to what might be causing this?

 

Camshaft sensor fine tunes the engine rotation position and is used in starting before the crankshaft sensor takes over that function in the run mode after it is started . If the camshaft sensor fails it takes more rotations to start as it reverts to the crankshaft but it doesn't know if it is reading the TDC of the #1 in the beginning of the ignition cycle or the opposite cylinder being TDC at the beginning of the intake cycle . The ECU will have to try both options before getting it right.

P0340 is the code for camshaft position sensor and can be verified for free as the auto parts store will read the OBD 2

 

Location on the back of the left cylinder bank

 

It is always best to start any trouble shooting by having the codes read. Even if the check engine light hasn't come on it can reveal codes pending. In your statement of the problem I would recommend having the fuel pressure checked.
The x308 when the key is turned starts the fuel pump and lets it run for 3 to 5 seconds to charge the rack and then shuts down. The supercharged has 2 fuel pumps. The primary is used for starting and general driving. Put the foot down and the engine needs more fuel so the 2nd pump kicks in.
When you have a primary fuel pump failure the ECU after fail to start will bypass the primary pump and use the secondary to run and start.
With a pressure gauge attached to the fuel schrader valve turn the key to ON not start and see if fuel pressure rises. If it doesn't then remove the relay for primary fuel pump and test again.
If you get fuel pressure then the primary pump is toast. Since you have to remove the tank I have always replaced both while I am in there.

 

Can you hear the #1 fuel pump turn on to prime the fuel lines before shutting off after 3 - 5 seconds as you rotate the key to run and not start position ?

 

What you should do in this case is simple; check this x308 forum on the same issue, either use google with 'jaguarforums' and 'x308' added, or the search function above.

There was a quite long thread which started exactly the same as yours, but I will be damned if I remember what finally caused the issue.

I guess it all started some 1/2 yr ago, the last post maybe 2 month ago.
He only found it after quite some work, but it might solve your problem a whole lot easier.

Sorry, I am on the road, not really in the position to search for you.

Edit: I think to remember it was the fuel pressure regulator.

 

Non turn valve failing, resulting in the fuel rail loosing pressure, cycle the ignition key a couple of times prior to attempting to fire the engine.

 

Thanks for all the responses, much appreciated

 

What was the solution in the end?

 

A new fuel pump was recommended, however due to the fault being intermittent my garage advised against spending the money.