Thermo Vacuum Valve?

[Rhino]

This may be a dumb question,but can someone please tell me what exactly the Thermo Vaccum Valve (TVV) does and how an unhooked vacuum line to the TVV (broken TVV port) can affect the performance of my engine..Possibly causing my idle surge???
Thanks!!

 

[steve]

Originally posted by Rhino
This may be a dumb question,but can someone please tell me what exactly the Thermo Vaccum Valve (TVV) does and how an unhooked vacuum line to the TVV (broken TVV port) can affect the performance of my engine..Possibly causing my idle surge???
Thanks!!

On the 4G63 it's used to control the EGR valve on the intake manifold so that the EGR valve doesn't open when the engine is cold. It can cause a couple of problems. It can cause the EGR to open when the engine in cold and it can cause a vacuum leak (and big boost leaks on turbo engines)

Steve