Hi Sixto. Thanks for the reply. Interesting point on the response time vs. constant pressure.

On air compressor hoses, I read that there is a drop in pressure over distance due to friction. I suppose the same would be true in this application, but we're talking a few feet distance. It makes me wonder if that is why the hard vacuum lines are used (smaller volume but/and/or less friction)? So, Im thinking of trying a hard line if I try tapping into the ALDA line. I can always drill and tap a hole on the other side later if it doesn't work well.

I opened the hood and looked at the configuration on my '93 300D. There is a single additional hard vacuum line on the ALDA-to-manifold circuit that disappears into the firewall. The vacuum schematic for my iteration shows that this line runs to the EDS, presumably to monitor boost pressure (which would make sense). Makes me wonder where the EDS resides anyway.

I have a couple of more questions ...

1) Any thoughts on setting the replacement actuator on 15 psi vs. 12 psi? The stock spec is between 13 and 14, so I'm thinking 12 psi to be on the safe side, especially if there is a potential pressure drop from coming around from the injector side of the engine.

2) Any guidance on bobodaclown's observation that the replacement actuator works in the reverse from stock (starts in the "fully on" position vs. in the "fully off" position)?

I assume this means that the starting position for the replacement actuator is all the way in (and it is pushed out by pressure) and the stock plunger would start out fully extended (and is pulled in by vacuum). Does this affect how the actuator should be installed? I assume the replacement actuator still needs to be modified to shorten it and add more threads ...

Thanks again.