OK well for a long time ive had this vac line just unhooked and capped....its an emissions one i believe but im having some idle problems so i want to make sure my whole vac system is all set...i blew in it and found out that it goes to the green plug on the right side of the engine. there is a line of 4 or 5 plugs with vac tubes that form upside down U's on the side with the spark plugs...it goes the green one thats furthest from the firewall. does anyone know where the otherside of that goes to?


-Matt

 

On the left side of the engine there is a green plug on a solenoid for the Twin Scroll. It's called.........the Twin Scroll Solenoid. It determines if the twin scoll actuator on the exaust manifold is in the open or shut position.

Anyway, that twin scoll actuator is open/shut by vacuum coming from that twin scroll solenoid with the green plug. No vacuum hose means the switching valve in the exaust manifold is wide open all the time instead of being shut under 2800rpm.

 

so will i have less lag if i plug it back in?

 

Yes.

Try reinstalling it. Then idle the engine while looking at the actuator on the turbo. Rev the engine to over 2800 and the actuator rod should be seen to move. Let off the rpms and it should retract.

The failure mode is to the wide open position on the twin scroll *flap* so in the worst case scenario you'd have just a touch slower response out of the turbo.

 

well i can already boost to 10 PSI by about 3000 rpms so im not that worried about it...but faster is always good....


Thanks,
-Matt