I found this turbo vacuum line disconnected

[jw113]

While replacing the crank position sensor (CPS) today I noticed a disconnected vacuum (?) line at the air inlet tube nearest the turbo inlet.

Here's before I reconnected it:

Turbo Line 1.jpg (59.18 KiB) Viewed 101 times

and here's after:

Turbo Line 2.jpg (68.24 KiB) Viewed 101 times

I found a vacuum line diagram online that suggests this is the "blue" line, but does anyone know what it does?

I've had the car 12 years and no one has done any work in that area, so who knows how long it's been disconnected. The car ran fine without it connected.

Thanks for any info.

[abscate]

The blue line returns the pressure that isn’t used by the turbo control valve back to the snorkel so no boost pressure is “lost”

If to pops off , the turbo will work fine but you may get a lean code for a vacuum leak if you have a light foot

[DavidE7]

The port for the hose that popped off doesn't have a barb or other retaining feature. It appears that the only way it is retained is with friction and the partial vacuum from the engine and turbo intake through the venturi (diameter reduction) on the intake pipe. A little spring clamp would probably be smart.

The larger hose above it for the carbon canister fuel vapor purge has a small barb on the port . On my three turbo charged vehicles, I found that plastic clip for holding the O2 sensor wire clipped to hold the hose from pulling off the barb. You may want to slide that clip downward to help retain that hose on its port.

I have chased enough false air faults with smoke that I think my cars will each get a spring clamp like the ones at the Turbo Control Valve on that small hose.

[vtl]

Light foot definitely, since TCV only triggers in high engine loads, when it needs to get rid of of boost quickly. Vacuum leak was probably minimal, fuel trim idn't migrate to out of range yet.