You mean the solenoid has voltage on one terminal all the time? I did more checking cleaning of the solenoid and got the power back, at least temporarily. The 300D T has being going back and forth on low power and "normal power" in the last few months. Anyway I think the overboost protection solenoid was partially blocked. After more cleaning and testing in blowing into a bowl of water, I verified that all ports are open including the atmospheric port and put with back together with a vacuum /pressure gauge tee-ed in at the overboost protection solenoid's output (port going to the ALDA). I used a vacuum Tee from my 240D parts car and it took 10 minutes to hook everything up and run the gauge into the cabin.

Here's a video (click to play) of the boost. At 60 MPH it shows about 5 psi. If I floor it< it goes to 10 PSI max. Is this OK or is there room for more boost? What should I adjust? the ALDA screw to get more fuel or the wastegate?

Oh yeah, notice my cracked console wood finish? If you have a good one please PM me.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked