: Optispark



dretwenty5
02-19-07, 09:36 PM
Somehow the hose that hooks up to the optispark has vanished. Where does the other end of the hose go?

BCs71
02-21-07, 01:46 PM
There are actually two vacuum hoses at the bottom of the optispark. One runs to the air intake boot, on top (with a blue elbow fitting), just before it enters the throttle body. see pic: http://www.badbodies.com/brian/cadem5.jpg
The other fitting runs alongside the driver's side of the intake manifold and into the center of the manifold, driver's side.

N0DIH
03-02-07, 09:03 AM
This is bad to lose, hook it up ASAP.

I occaisionally check my vent system integrity by connecting up a vacuum pump to the line to one side and plug the other and ensure it holds at least 15 inches for a while. Good opti maint!

With oil getting on the lines at the bottom there they get soft and can fail or collapse. A new opti vacuum harness isn't too expensive from GM and worth it if yours is missing or failing.

Only mod I would recommend is reroute the vacuum line from the air intake to the inside of the car somehow, draws in drier air that way.