Vacuum Problems...HELP please...

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Old Nov 26, 2016 | 06:18 PM
  #1  
1980crimsonCutty's Avatar
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Unhappy Vacuum Problems...HELP please...

I am having a terrible time trying to get my vacuum lines hooked up right after a buddy of mine put on my new rebuilt carb (holley 650). If anyone could take a look at these pictures and possibly help me out I would greatly appreciate it. Right now neither the canister or vacuum bulb are hooked up. I would like to eventually get my heater controls for heat, ac, defrost hooked up right too but for right now I just want to get it running right. If you need better pics or have questions please let me know...










Old Nov 27, 2016 | 07:40 AM
  #2  
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There are only two kinds of vacuum sources on an engine - straight manifold and ported (timed). The only things that use ported vacuum are the EGR valve, the evap canister purge, and the distributor vacuum advance (if you still use ported vacuum for advance). Everything else uses straight manifold vacuum, and EVERY manifold vacuum port is equivalent. PCV, power brakes, AT modulator, HVAC, and vacuum accessories all use any available manifold vacuum port. The specific one is irrelevant, they all function the same.

A manifold vacuum port will be at full vacuum at idle and drop off as throttle is opened. Ported vacuum is zero at idle, then climbs to match manifold vacuum as the throttle blades uncover the port in the venturi.
Old Nov 28, 2016 | 07:34 AM
  #3  
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Thumbs up Thanks!

Thanks for the info joe_padavano...I went out and tinkered with it a bit and now it is running GREAT! You explained it very well for my vacuum novice experience to work through. Now to replace my valve cover gaskets to stop the oil from dripping on my exhaust. I do know how to do that one...
Thanks again!

Originally Posted by joe_padavano
There are only two kinds of vacuum sources on an engine - straight manifold and ported (timed). The only things that use ported vacuum are the EGR valve, the evap canister purge, and the distributor vacuum advance (if you still use ported vacuum for advance). Everything else uses straight manifold vacuum, and EVERY manifold vacuum port is equivalent. PCV, power brakes, AT modulator, HVAC, and vacuum accessories all use any available manifold vacuum port. The specific one is irrelevant, they all function the same.

A manifold vacuum port will be at full vacuum at idle and drop off as throttle is opened. Ported vacuum is zero at idle, then climbs to match manifold vacuum as the throttle blades uncover the port in the venturi.
Old Jun 2, 2024 | 08:38 AM
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If the large black hose connected to a brass fitting is the fuel supply, it needs a clamp NOW. I don't care for rubber hose on the pressure side of a fuel pump. Factory supply was steel line with threaded nuts. At a minimum if you stay with rubber hose use something rated for fuel injection with fuel injection clamps, make sure the hose is secured away from anything that can burn or chafe through it...I've personally seen this scenario/set-up go very wrong and turn into a serious fire.
Old Jun 2, 2024 | 08:55 AM
  #5  
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x2

It looks like there is no hose clamp on the fuel hose going to the fuel filter
Old Jun 2, 2024 | 09:10 AM
  #6  
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Originally Posted by Sugar Bear
If the large black hose connected to a brass fitting is the fuel supply, it needs a clamp NOW. I don't care for rubber hose on the pressure side of a fuel pump. Factory supply was steel line with threaded nuts. At a minimum if you stay with rubber hose use something rated for fuel injection with fuel injection clamps, make sure the hose is secured away from anything that can burn or chafe through it...I've personally seen this scenario/set-up go very wrong and turn into a serious fire.
Originally Posted by Olds64
x2

It looks like there is no hose clamp on the fuel hose going to the fuel filter

OP has not logged into this site since May 2nd, 2017 09:08 PM; still, your recommendations are noteworthy. 🤣😎👍👍👍
Old Jun 2, 2024 | 09:49 AM
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:d
Old Jun 2, 2024 | 01:19 PM
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Maybe on May 3, 2017 there was a great engine fire. LOL! Looking at a dead thread happens to everyone, especially with the related thread scrolls. Anyone who says differently is lying.
Old Jun 2, 2024 | 03:26 PM
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Originally Posted by 69HO43
Maybe on May 3, 2017 there was a great engine fire. LOL! Looking at a dead thread happens to everyone, especially with the related thread scrolls. Anyone who says differently is lying.
True. The possibilities are endless.
Old Jun 3, 2024 | 04:20 AM
  #10  
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DOH!
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