IIRC, that is the overboost valve....The intake manifold connection goes in one way and the line from the ALDA goes in the other way, and I think the switch is powered by a sensor on the intake manifold. If there's too much, it'll cut that switch off and the other "nipple" thing is actually a vent.


The thing that really helped me is to trace back both of the lines connected to that valve (the brass/silver box) and clean both of those lines really good. On my 300, the vent is up, yours appears to be upside down but i cant tell which way is up.

There's a banjo bolt (a hollow bolt with holes that makes air go from the ALDA and the intake to the tubing, and those get clogged up. Clean that out, it helped my acceleration

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Java Developer/Linux SysAdmin

Current:
*1984 300D ~200K,1989 MR2 250K, 2012 Ford Fusion 4.5K (fiance's car to replace the uber-unsafe cavalier)
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Past: 1998 Chevy Cavalier ,2005 Saab 9-3 2.0T, 1996 Mazda Protege, 1974 Porsche 914 2.0, 1997 Land Rover Discovery 4.0L/5Speed, 1995 Jeep Wrangler