Thread: Vacume Tree question & Pcv question

Where does the middle nipple go? I have seen them capped and some not capped.



How would i connect this pcv to properly function? I looked at the pcv harness on my L36 and there is 3 wires on it. This pcv has a 2 wire harness female plug.

Middle port on the tree is for the HVAC system, it actuates the blend doors. On the L36, it's connected where the brake booster is connected.

The second pic appears to be an EVAP purge solenoid, maybe? Can't tell for sure, but it's not part of the PCV system. I don't have a wiring diagram handy.

Originally Posted by Scimmia

Middle port on the tree is for the HVAC system, it actuates the blend doors. On the L36, it's connected where the brake booster is connected.

Yep. You see it capped on some engines because 04+ Impalas/Montes and a lot of Bonnies have electronic HVAC systems, so no need for a vacuum line. I got lucky and mine came capped, so I don't need to find a cap for it.

Originally Posted by Scimmia

The second pic appears to be an EVAP purge solenoid, maybe? Can't tell for sure, but it's not part of the PCV system. I don't have a wiring diagram handy.

Yep, looks like the EVAP solenoid. The PCV system has no electronics...

where that evap solenoid goes on my gen v is right below the pcv valve (where everyone seems to block it off and run a breather instead) I am un-sure how to properly connect that evap since i don't want un-metered air entering from a breather and possibly go to lean.

I broke my old vacuum tree where that middle nipple was blocked off, I got a new one and its no longer capped. My Hvac is all electronic. Do i need to tap into that nipple or cap it? If i should cap it, instead could i run a line from a boost gauge to that nipple?

All electronic on a 99 GP GT? First I've heard of that, even the electronic control units use vac to control the doors, I believe.

No go on the boost gauge to that nipple, it's before the supercharger

ah yes that makes sense with the boost gauge. I guess I have to run a line from the tree to the hvac? im not sure...

If you have vacuum operated blend doors (which you do, since all 97-03 GPs do) and want them to work, yes you need to run a vacuum line to that port.