Do some simple troubleshooting. Tooooooooooooo easy-----------
First, does the outer door open when the engine is shut off? It should.
The vacuum pod which actuates the outer door is simply a rubber diaphragm with a spring pressing against it. If there are no holes or cracks in the diaphragm, then when manifold vacuum is applied to the pod, the diaphragm overides the tension of the spring pushing against it and then pulls the rod which is connected to the outer door. When manifold vacuum drops low, or completely goes away, the spring inside the pod pushes against the diaphragm and the rod pushes open the outer door. When a vacuum is applied to the pod, there should NOT be any leak. So, disconnect the vac hose from the engine, apply a vacuum and see if the pod will remain closed.
Part of the vac system for the outer door includes a check valve spliced in the vac supply hose to the pod. This check valve allows vacuum to flow freely ONLY IN ONE direction. Therefore, if operating properly, the check valve should flow easily one way and have a significant resistance to flow the other way. You can use a vacuum pump/gauge to check the flow in both directions, but the simplest way to check it is simply to just suck on each end of the valve. There should be a noticeable difference when sucking on each end. The side of the check valve which has a noticeable resistance to vacuum goes TOWARD manifold vacuum.
Now, lets stop right here.
There are TWO types of engine vacuum: manifold and ported (or venturi vacuum if you prefer).
Manifold vacuum is ANY vacuum source BELOW the throttle plates of the carb.
Ported (or venturi) vacuum is ABOVE the throttle plates.
During hard acceleration (or a heavy load condition), manifold vacuum will drop drastically, or even go to zero. Whereas, ported vacuum INCREASES with hard acceleration or a heavy power load. Therefore, if you have the vac hole for the outer door pod connected to a ported vac source-----------------IT WILL NOT OPEN DURING HEAVY ACCELERATION. IT MUST BE CONNECTED TO MANIFOLD VACUUM!!!! From the factory, it was connected to a fitting in the rear intake runner.
The outer door for a CI hood functions better with a manual tranny car than it does with an auto tranny car. The reason for this is because with a manual tranny, when you depress the throttle, the load is fixed (if that is a good explanation), as opposed to an auto tranny because if you accelerate hard enough with an auto tranny, it will down shift which allows the rpm to increase, which decreases the load on the engine and manifold vacuum jumps up and the vac pos closes the outer door. Does that make sense to everyone?
For example, if you are driving 30mph with an auto tranny, push the gas pedal down, the tranny immediately down shifts and manifold remains relatively high and the outer door stays closed, or doesn't open much. With a manual tranny car, when you accelerate, and leave the tranny in 4th gear, the manifold vac drops WAY down and will not increase until the load on the engine decreases. Thus, the outer door opens faster and stays open longer-----------------------if everything is properly connected and functioning properly. :thumbsup:
The inner door is opened/closed by an electric solenoid, and that solenoid is activated by an elec switch on the accelerator pedal when the pedal is pushed to the floor. Thus, the inner door is either fully open, or fully closed------------no inbetween for it.