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6/29/11 9:59pm - Original Message: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600
Ok so tonight I found a missing vacuum line on my cruise control, the port nearest the fender. I dont particulary care if the cruise works, but could this be root cause of my persistant vacuum issues???
 
Also after reviewing the assembley manual I am even more confused as to the routing of the vac lines.
The missing line is supposed to leave the cruise transducer and head into the intake mainfold vacuum fitting (6L)......This is on page 340 of the MAM assembly manual,
 
but then on page 461 of the same manual, its showing a vac line straight from the vac tank up in the front end to the 6L fitting....a no cruise car i assume.
 
The latter is the way my car is set up........
 
How is it supposed to be or how can I bypass this mess?
 
Could blocking off the open port on the cruise add more vac to my system and perhaps remedy my problems or am I just grasping at straws????
 
 
The Rook2011-07-01 13:28:14
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6/29/11 10:49pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
I can e-mail ya the diagram, if it would help....
You can plug all of the cruize vac lines, ifin ya want. Make sure there is no vacuum leaking at the brake switch, too...



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Joel Adams
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6/30/11 9:06am - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600
Thanks Joel....drawing recieved.....

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7/1/11 4:18pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600
OK Now Im hijacking my own thread......
Im confused as to something I'm reading from Edelbrocks instructions...
See This link
 
Is my distributor vacuum timed or full??? Im not home to stick my fat finger in there.......
 
Also i have no emission items on my car so according to fig 1 should my distributor vac line be on the manifold vac side???
 
I know for a fact it is not......could this now be the problem? or doesnt it really matter???
 
And lastly should I adjust the linkage that controls the accelerator pump? Edelbrock sugguests this for cars that hesistate off the line. saying I should try moving the linkage closer to the carb. At least thats the way I read it.
The Rook2011-07-01 13:21:29

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7/1/11 7:24pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
rraider1
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Woodland, WA - USA

Vette(s):
1977 T-Top,350,Auto Black Ruby Pearl,Steeroids R&P conversion

Joined: 10/14/2003
Posts: 1152
Hope this helps it comes from a good article on tunning with vacum pm me your email I can send it. its in PDF format

Manifold vacuum is very easy to tap and utilize: Simply drill a hole in the intake manifold and stick a hose in it. This vacuum can then be used to power accessories (headlight doors and heater controls), or it can be used as a signal source based on how hard the engine is working. One such signal source application is distributor vacuum advance: When the engine is working lightly (high vacuum produced), the ignition is advanced, and as the engine loses vacuum due to the throttle being mashed to the floor, vacuum is lost and ignition is retarded. Pretty simple. But what if you want to “switch” the vacuum on and off based on whether the engine is just idling or in cruise mode? Enter the term “Ported or Timed Vacuum .” Off at Idle, on with throttle open.

rraider12011-07-01 16:26:11

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7/1/11 8:15pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
Jaws79 Lifetime Member
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Sykesville, MD - USA

Vette(s):
1979 Corvette Coupe Corvette Light Blue Midnight Blue interior Mirrored Glass T-tops

Joined: 4/27/2008
Posts: 4211
Also, Dan, I did speak to Lew concerning your carb. He said the 750 is way too big for your setup, it should be 600 to 650. He said if your can bring the car down (a long way, I know) he would be glad to rejet and set up the carb. Also, in your link it said not to use fuel with alcohol in it. Actually NO carbs should run gas with alcohol in it, but since we have to, I use an additive called Star-Tron, which takes the moisture out of the gas that alcohol brings in. HTH
 
Barry
 
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Lifetime Member #181
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7/1/11 10:43pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600
Thanks  for the hookup barry, I may indeed take you up on that because i think it still needs a fine tuning. I have great news, I adusted the accelerator linkage (nearer to the carb)and the hesistation is gone.....YIPEEEEEEE!!!!

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7/5/11 8:06pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600

Quick update.......I changed all the vac line this weekend up to the firewall. There was a minor improvement in the AC air, a faint bit of cool air through the vents. Tomorrow Im going to pull the glove box and dash and dig in up front.

I did find something that was peculiar and  had a question. Does it matter if the vac line for the heater AC controls isnt running through the check valve?
Mine was coming directly out of the opposite side of the vac port screwed into my manifold......and because it wasnt running through the check valve could that be a possible leak source, as the vac could then escape back into the mainfold when the engine is off???
The Rook2011-07-05 17:06:31

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7/5/11 11:20pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19449
The check-valve in the hvac system is to keep the doors from closing when you get on the accelerator, and the vacuum drops. It just keeps the doors in the correct position while the vacuum is dropping. Not having a check-valve in that line shouldn't effect the way the engine runs, but it certainly would help that hvac system work mo betta.


btw...I moved this thread to the "Engine" forum...it's better suited here.
Adams' Apple2011-07-05 20:35:24

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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7/7/11 2:44pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
The Rook Lifetime Member
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Pittsburgh, PA - USA

Vette(s):
1979 L-82, 3 spd auto, car was originally Lt. Beige currently painted Sportsman Red, Doeskin leather interior, 103,000 miles......

Joined: 12/4/2002
Posts: 600
All is repaired....as originally thought, the radio guys pulled out the connectors at the AC control when jambing my sirius unit in there.  At least all of my vac lines are brand new now.......
Thanks for putting up with my whining everyone........

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7/7/11 5:19pm - Reply: 'Vacuum woes continue HIJACKED 7-1-11'
Jaws79 Lifetime Member
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Sykesville, MD - USA

Vette(s):
1979 Corvette Coupe Corvette Light Blue Midnight Blue interior Mirrored Glass T-tops

Joined: 4/27/2008
Posts: 4211
That's what we're here for! Venting is good for you! Glad it's working now! Now no excuses for Carlisle!
 
Barry
 
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Lifetime Member #181
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