You should have a switch mounted on the throttle arm/lever, inside the engine compartment, a relay on the firewall on the passenger side, and a solenoid attached to the flapper valve at the opening in the back of the cowl hood. Switch on the throttle lever should only be activated at wide-open throttle, which then actuates the solenoid via the relay to open the flapper valve. Wiring harness should run from the firewall just above the fuse block to the throttle lever switch, and also through the firewall wiring gutter to the relay and flapper solenoid.
Can you post a picture of what you have?