Got my car back from the shop today. They sorted out many of the problems that I inherited when I bought the car about 6 weeks ago.

One "new" problem according to the tech is that VVT on the right bank seems to not be working or working intermittently. The VVT solenoid on that side was taken apart during removal of the head, cleaned, tested and reinstalled.

It was suggested that I should drive the car for a couple of weeks to see if that will clear out any passages of the VVT so the oil pressure can activate the mechanism properly.

I know that the VVT comes more into play when the engine is at higher rpms but I have a question on how it affects lower end rpms - especially idle.

The BIG problem is that the car seems to be idling a little rough, especially when in gear and at a stand still or just starting to accelerate. Initially the engine just had a loping but now it seems like the idle. How could the car be doing this when the cylinder pressures are up after valves were replaced?

Would a faulty VVT on one side cause this idle problem?

BTW, the engine seems to perform fine at higher speeds/rpms.

Interested in any comments.

 

The VVT's should be 'off' at idle and then engage as RPM's reach something like 1200 - 1500. On the AJ27 engine, which you have, the VVT's are constantly variable under electrical control of the ECM. There have been reports of them being replaced when the issue turned out to be electrical. You can observe the electrical operation of the valves with a VOM.

Did the repair tech say anything about the interior of the engine being gunked up with oil sludge? If clean then there is probably not a blockage in the oil passages. If gunked up there may be even more issues. Normal repair to the VVT's is a heavier weight oil or a can of 'Restore' which will thicken the existing oil.

As far as the strange idle, having 2 cylinders on one bank 10-15% low on compression could certainly contribute to that.

Sorry about your difficult introduction to the Jaguar!

 

I disconnected both VVTs as a test today and it did NOT seem to make a difference at any speed.

They instructed me to give the car a go for a week or two and then to swing by to run some diagnostics. In the mean time I will check the spark plugs to look for some curious carbon build up or for wet plugs. (BTW, the proper, higher end NGK plugs were just installed - a $ 100.00 for a set of plugs, amazing).

Yes, this has been a rather poor entrance to Jaguar ownership. Had I known a little more info on this car I would/should have passed.

I guess we will see how things rock out over the next few weeks.