Author Topic: No vacuum signal  (Read 4547 times)

sixt9x33rs

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No vacuum signal
« on: September 04, 2011, 03:24:58 AM »
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
'69 RS Z/28 65B, 711 Flat hood no spoiler, endura, 4:10 43K miles
69 X77 Z/28 69 69 711 Original Paint Unrestored (Sold)
'69 X66 Convertible 69B 712 auto, (Sold) 44K miles

JohnZ

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Re: No vacuum signal
« Reply #1 on: September 04, 2011, 03:14:31 PM »
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.
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sixt9x33rs

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Re: No vacuum signal
« Reply #2 on: September 05, 2011, 01:44:38 AM »
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?
'69 RS Z/28 65B, 711 Flat hood no spoiler, endura, 4:10 43K miles
69 X77 Z/28 69 69 711 Original Paint Unrestored (Sold)
'69 X66 Convertible 69B 712 auto, (Sold) 44K miles

Gramps69Z

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Re: No vacuum signal
« Reply #3 on: September 05, 2011, 02:19:03 AM »
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.
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JohnZ

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Re: No vacuum signal
« Reply #4 on: September 05, 2011, 03:45:40 PM »
<<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
'69 Z/28
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sixt9x33rs

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Re: No vacuum signal
« Reply #5 on: September 06, 2011, 05:45:06 PM »
Thank you
'69 RS Z/28 65B, 711 Flat hood no spoiler, endura, 4:10 43K miles
69 X77 Z/28 69 69 711 Original Paint Unrestored (Sold)
'69 X66 Convertible 69B 712 auto, (Sold) 44K miles

 

anything