Updated post: Currently using 3.0T solenoid valve 7.00887.22.0. Be careful when removing the vent cover. It may be sticky or designed not to be pulled. You need to remove the round cover first, take out the filter sponge inside, remove the edges, slowly pry it open, and then take it out. Be sure to remove carefully. My original 7.00887.21.0 solenoid was damaged just by prying open the ATM.
Solenoid Connections I wired the vent cover following
@JPuehl 's wiring method. The boost end is connected to ATM for boost, OUT is connected to WGA, and VAC is connected to ATM. After two days of testing, the boost value is about 0.7bar. I did a test today, following
@wheela 's suggestion of connecting the boost end to ATM and the OUT port to WGA. The VAC is connected to the atmosphere as well as to the oil and gas filter. The boost value is about 1bar-1.1bar. When the VAC is connected to the ATM, the voltage boost value is relatively low.
PS: The boost end originally had an adapter as the boost end, but later it was replaced with a pagoda screw to lock it behind the throttle. Since the booster end interface is larger, I estimate the flow rate will be greater. Both boost response and throttle response have been improved
. WDGC remains in the low 40-50% range. I will replace the 1.5bar spring and test it in a few days. If the boost value doesn't change, I'll retune the ECU.