I have a question regarding the vvt operation on a 98 xk 8.

I worked with Tom (Windy city xk8) and we replaced secondary tensioners thinking that was the source of the clatter in the engine at certain rpm's. after the tensioner change we discovered that it was actually the passenger side vvt making all of the noise. (LH drive) We found that when we disconnected the rh side vvt the noise goes away. Per the suggestions of a few folks on the forum Tom added some "restore" to the oil to thicken it up but it doesn't seem to have helped.

On the 98 it is my understanding that the vvt is either on or off at or above around 1400-1500 rpm is this correct or is it variable based on rpm? I thought I had read that the newer engines had variable vvt based on rpm etc...

If it is simple on or off I should be able to attach a scope to the leads and monitor to see if the electrical signal is intermittent and I can use the drivers side as a working example to follow. Where is the other end of the vvt cable connected to? I am thinking that if it is electrical it might be a bad connection and when it turns on the circuit momentarily opens up or simply cant carry enough current to support the solenoid and that is what is causing the clatter. It sounds as if the vvt is turning on and off very rapidly abd that is the clatter we are hearing but I could be wrong

any thoughts or guidance?

Thanks in advance for the help or guide to a previous thread.

Barry

 

Here's some info on the early VVT system from Jaguar documents...attached as a PDF below.

Good luck.

 

You can also read this thread.
https://www.jaguarforums.com/forum/x...uestion-73211/