No vacuum signal

[sixt9x33rs]

I have a 67 quadrajet on my 69 convertible. I have the stock vacuum lines attached to the distributor, I have no vacuum signal to the vacuum can on the distributor. I have the hose connected to the front port of the carb just like the original setup. Any idea why I don't have a signal here?

Thanks

Lawrence

[JohnZ]

I have a 67 quadrajet on my 69 convertible. I have the stock vacuum lines attached to the distributor, I have no vacuum signal to the vacuum can on the distributor. I have the hose connected to the front port of the carb just like the original setup. Any idea why I don't have a signal here?

Thanks

Lawrence

Most likely because that carb is designed for a "ported" vacuum connection; cap it off and look for a connection that provides full manifold vacuum at idle. If you can't find one on the carb, use the vacuum fitting on the intake behind the carb.

[sixt9x33rs]

John this must explain why the distributor was hooked up to a different portnbefore I started to work on it. I will go back to the other source.

BTW, what does "ported" vacuum mean vs manifold vacuum?

[Gramps69Z]

BTW, what does "ported" vacuum mean vs manifold vacuum?

With ported you are relying on the position of the throttle plates and with manifold it's constant.

[JohnZ]

<<BTW, what does "ported" vacuum mean vs manifold vacuum?>>


This will explain about ignition timing, advance systems, and full manifold-vs.-"ported" vacuum:

http://www.camaros.org/pdf/timing101.pdf

[sixt9x33rs]

Thank you