Hello,

I am new to the forum, but thought I would try this out to see if I could get some better results. I have a 98 xj8 4.0l. 92000 miles. Sometimes the car cranks right up and some times you have to try 2 or 3 times to get it started. Once it starts it seems to run fine. It has been at the local dealer for 3 weeks now with the following results. They found that the vvt is setting codes. Not sure which codes yet, but I am picking the car up this saturday and will get that info. Does this sound like a possible issue, and how much do the vvt solenoids and parts cost? I was told by the service advisor that I was looking at $1900 dollars a piece. ????? I am not a jaguar mechanic, but this sounds a little unreasonable to me. I understand that the vvt controls the intake valve timing and if sticking could be causing my no start issue.

I was also told that it was not a compression or cam timing issue, and that somewhere down the line the wire for the vvt circuit was removed from the ecm connector to hide the vvt problem.

Any thoughts or ideas would be great!!

Logan

 

The VVT issue is not contributing to the no start situation. The VVT is operated by oil pressure and only is activated at, I believe, above 1500 rpm.

I would start with the big three, fuel, spark and compression. Hook up a fuel pressure gauge to the valve at the rear of the right valve cover. You should have above 40 psi there. Turn the key to the 'run' position and you should hear the fuel pump run for 2-3 seconds bringing the pressure above 40. I suggest starting with fuel pressure because there are no sensors or codes associated with a failure here, only starting/running issues.

I also question why anyone would have gone to the trouble of removing a wire from a connector at the ECM. It would be so much easier to disable the electrically operated valve at the valve. Sounds like the tech miscounted the connector wiring. The VVT valves might be a couple hundred at the Jaguar parts counter but are very simple to replace. The VVT itself might be a lot more.

Overall starting issue story is not really believable despite VVT codes. Go to the XK8/R forum FAQ sticky and look for the ODB code chart. I cannot imagine any link between the VVT and starting.

 

Thank you for your reply. This is a lot of help. The service manager at the dealer told me that the vvt was sticking causing the intake valves to be stuck in the advanced position. If this is true it would only be the valve correct? Even so, it should still start right? I would not think it would advance the timing that much. I will start with the fuel pressure and see what I can come up with.

Thanks,

Logan

 

VVT failure is usually the result of wear addressed by raising the 'weight' of the oil. If one of the units is stuck in the advanced position I would suspect that the engine would be experiencing a substantial level of vibration due to the difference in valve timing on the two banks. If an unit is stuck what with all the missing wire discussion?

Check the fuel system.