I'm trying to tshoot a problem where my two middle vents don't blow AC, trans shifts hard, car is anemic- you have to really work it to get turbo to kick. I've swapped the 2 Y31 transducers to no avail. I'm searching for bad lines/leaks. The jpg of the vacuum schematic I have doesn't have very good resolution. What happens to the line after 62a inline air filter? I pulled the batter to look at that mess of wires under there and there's no output to that air filter- e.g. no line attached.

If you can get air out of the footwell registers, the problem is more likely a bad center vent actuator pod. If air goes through the defrost registers regardless of ACC setting, the problem is more likely source vacuum, if it's a vacuum problem at all.

Consider keeping the vacuum system separate from boost management - Wastegate actuator swap for OM602.962?

Black lines typically are system vents that just end.

Put a vacuum gauge on the small fitting atop the engine vacuum pump and report back.

Sixto
87 300D

This thread should help - W124 '92 300D 2.5 downshift clunks won't go away

Sixto
87 300D

Thanks, but my question remains- am I missing a line that comes out of the air filter that runs beside the battery- back in the direction of the passenger compartment.

The line after 62a goes through the false firewall, possibly into the cabin, then ends. It's just a vent for the vacuum system. It's an open end, no cap or plug. Ergo, it doesn't matter that there's no line attached to the far end of 62a

Sixto
87 300D

I know almost nothing about vehicles. I'm not a shade tree mechanic- I'm just a cheapskate. I had just bought a 92 W123 300d with grease kit installed- I even avoided having to install that!

On the way home, AFTER buying it, when I got out on the open road, I noticed it was not running right. When I tested it it was in a residential area and it was driving fine.. if a bit noisy in the transmission.

I bought the MityVac kit and started testing vacuum based on what everyone was saying on this forum and found a right angle connector that joined the line straight from the vacuum to the T that was either leaking or was simply inadequate. The right angle was very narrow on one end and bigger on the other angle. This seemed wrong since it was coming straight out of the vacuum. I cut out a small piece of the hard clear plastic line that I had excess of and shoved it in place of this right angle and BOOM everthing is working well. Okay, not everything, the AC is still blowing wrong but it's cold and the turbo works and the transmission is quiet. I'm so happy! Thanks to everyone on these forums.