Not sure which VVT you have, I know they changed somewhere after introducing the S4. I have an S3 and so what you did and listen for the click when you open the butterfly so far. I also just put 12V to the solenoid and look through the inspection hole on the VVT and confirm the plunger is extending. Beyond that I am not sure of any way to be sure that it is working except by the butt dyno....

 

Not sure which VVT you have, I know they changed somewhere after introducing the S4. I have an S3 and do what you did and listen for the click when you open the butterfly so far. I also just put 12V to the solenoid and look through the inspection hole on the VVT and confirm the plunger is extending. Beyond that I am not sure of any way to be sure that it is working except by the butt dyno....

 

If it's an 87 then it's an S3.

 

Was wondering why OP said S4......

 

If, the vvt clicks (plunger jumps out) when you snap the throttle (car not running), you've confirmed its working electrically. To make sure its working mechanically, pull the electrical connector off the vvt, start the car, and then apply 12v to the terminals (not polarity specific). The idle should get lumpy within a second or so which means its mechanically working (advancing the timing).