I had my boost control solenoid off the other day while doing the PCV system replacement on my '94 850 Turbo. Other than the middle hose to the air intake, does it matter which hoses go where off the turbo? What happens if I reverse them? Also, my factory turbo gauge is not showing vacuum or turbo pressure now. Where do I run that hose to? Thanks.

 

 

I have been fighting this for a very long time on my 96 854, the diagram here is correct, but the COLORS are wrong (maybe the TCV on your car was twisted 180 degrees).

When installed per the diagram (connector on the TCV closest to the engine side) then Yellow is on top, Blue in the middle, Red on the bottom.

Yellow (top) = Compressor
Blue (middle) = Intake Pipe (pre turbo)
Red (bottom) = wastegate

The hose from the CBV goes back to the intake manifold.

I just had this issue on my car last week, and my car was at a Volvo dealer for an unrelated knock sensor issue, but my computer was throwing an overboost code (doesn't illuminate CEL). Technician double checked my hose routing and found that the top and bottom was swapped (just like this image is incorrectly color coded). Again MAYBE your TCV is actually twisted 180 degrees, in which case my above data is reversed. I even double checked all my hoses and clamps last night and wanted to share my findings here. It can be very misleading.