A3 3.2 VVT Cam actuator Solenoid problem

[zeba5]

Hello. I'm experiencing an issue that's been going on since the day i bought the car, but now it seems to be way worse.
I always thought that the idle issue i had (which was sporadic) was due to the lack of software update to my specific ecu model. The car might idle like crazy, with a way noticeable shaking and all i had to do to solve it was to rev it once.
But now that happens ALL the time. I notice that if i hit around the top vvt solenoid with a screwdriver the car would idle fine again but only for about 5-10 seconds.
If i run the car with that soleoind unplugged the car idles fine but the power loss is noticeable and even the sound of the car is different.

I don't really know how to test or see if the soleoind went bad. All i did was measure voltage of both actuators and i found out that they are both on 13v constant. EVEN with the car turned completely off and ignition in off. Voltage doesn't vary either with RPM, it's always 13v constant. Like if the supply is ran diretclty from the alternator.
I tried to find some information about the solenoids voltage and all i found was info about audi a6 and w8 engines. And from what i saw those are run on 5v supply not 12. So i'm not sure if my solenoids are the same or not.

Here's a video. (i thought the idling issue was due a broken pcv diaphragm and that's why i tapped it like that)

 

[aqibi2000]

A lot of solenoid are ground switched, so basically always have 12V connected to one side but the ground side which completes the loop is controlled... Which will expo the reason you think the solenoid is always 'on' where as the measurement method is incorrect.


The simplest way to confirm the solenoid is receiving the power switching switching on and off is to connect the multimeter red probe to the 12V battery and black probe to the switched side of the solenoid (not the side which reads 12v).

When the solenoid is switched on (ground switch), then the black probe will also be switched to ground completing the circuit thus it will also read 12V. ( This will confirm the voltage being correctly present and switching on and off, and wiring being intact but not the actual actuation of the solenoid. For that you'll need a oscilloscope to measure the inductive back emf when it is on and off to confirm it is moving

 

[aqibi2000]

Solenoids do have a failure mode where they tend to stick and tapping them can cause them to operate

 

[zeba5]

A lot of solenoid are ground switched, so basically always have 12V connected to one side but the ground side which completes the loop is controlled... Which will expo the reason you think the solenoid is always 'on' where as the measurement method is incorrect.


The simplest way to confirm the solenoid is receiving the power switching switching on and off is to connect the multimeter red probe to the 12V battery and black probe to the switched side of the solenoid (not the side which reads 12v).

When the solenoid is switched on (ground switch), then the black probe will also be switched to ground completing the circuit thus it will also read 12V. ( This will confirm the voltage being correctly present and switching on and off, and wiring being intact but not the actual actuation of the solenoid. For that you'll need a oscilloscope to measure the inductive back emf when it is on and off to confirm it is moving

Ok i'll try to test that. I was worried because i read that (at least in a6's engine) they are ran on 5v not 12. In fact, the procedure to unstick them was to apply 12v for a couple of seconds.

Is there any thing i could check/see with vcds ?