I had a question I was hoping someone could me with. I recently put a cowl induction hood on my Chevelle and at this point only hooked up the vacuum portion. The flapper (door) closes when the engine is running and opens when off, however it does not open when I jump on it. I am trying to understand how the engine loses vacuum to allow the door to open, the vacuum is plugged into the same place as the power brake booster and the modulator valve, do these also lose vacuum? I guess I am missing something, can anyone help me understand how this works do I need to hook the electrical part up even though they seem to be totally independent. Thanks in advance for any help.

Ill take a guess at it. From my understanding the reason it opens is because there is no vaccum, when you turn it on you get vaccum at idle and when you step on it there should be little to no vaccum. If anyone wants to verify my understanding or fix the facts please do

Andrew

A search on this subject will give you all the info you'll ever need about cowl induction.:thumbsup:

Does the door shut gradually when you start the car, or does it snap shut? Do you have the check valve in the hose to the vacuum can? Is your vacuum hose routed through the notch on the passenger side of the hood, so that it doesn't get pinched when the hood is shut? If it is, then you may need to take a pair of channel locks and bend the lip of the firewall down about 1/8-1/4".

If you have a check valve inline on the hose, it may installed backwards.