Yes, the dreaded no boost in the W124. I just changed out the engine shut off valve, and now there is no boost. There is EDS error 3 (meaning the air sensor b2/1 - which I didn't touch BTW). Somehow the EDS thinks there is a problem with air flow.

I've checked with a pressure meter at the intake port - there is no boost, maybe 2 or 3 psi at WOT. So I put my mityvac on the wastegate and gave it 13 mmHG while driving to close the wastegate and make turbo. Boost rose to 7 psi for a short time and then dropped down again. Does that mean a leak?

Also, when I apply vacuum to the ALDA only, it leaks slowly - about 10 seconds for 10 mmHg.

So where the hell is my boost gone? The ARV and EGR seem to be working fine. How do I tell if the turbo is actually spinning up or not?

Any help appreciated. Got to get this thing going properly by tomorrow, or the wife will have my head on a stick.

EDIT: I did adjust the ALDA - turned the screw 3 turns out from fully in. I've also tried without the ALDA on and the vacuum line plugged. I've tried it with the screw all the way out, and all the way in. Same results, which makes sense since the ALDA is only reacting to what the boost is doing. So my conclusion so far is that the ALDA is not the cause of the boost problem. The real cause is something thinking there is a problem with the air sensor. And I don't know how to test it without the hook up box.

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1983 240D Silver/Blue "Sadie", unknown miles. 100k miles on WVO single tank, converted to 2 tank about 10k miles ago, FPHE, Injector Heaters, Aux Fuel pump. Alcohol/Water injection. Frantz oil bypass filter
1992 300D 2.5 Turbo Green/Tan "Jade" 267K miles Stock.
1992 300D 2.5 tan/tan "Rocky" on 2 tank WVO. Pressure actuated Turbo "rat's nest" surgery completed. 197k miles