We just put a Drag 3 on a 99si. With the MAP sensor on the throttle body connected the car starts and runs fine. If we hook up the map sensor with the check valves the car shuts down immediatly, if we feather the gas it will barely stay running. Has anyone else had this problem? Is there a certain combination of directions that the valves face? We're ordering a missing link, so for right now the car is parked, but we need it up asap. Any info would be greatly appereciated. Thank you

 

The should all be the same way... blow through the valve to find out the flow direction they allow.

They should be t'd into a vacuum line that still runs directly to the MAP.

like this.

Vacuum line _____________________
T's with one .......|......|......|......|
way valves .......[_]...[_]...[_]...[_]
attached. Open to the atmosphere... so boost bleeds off, not blocked from the MAP.

 

Hey, that worked perfectly. I figured we set up the check valves incorrectly, and that fixed the problem. The diagram that you sent was perfect. Once again, thank you.