Best place to hook up vacuum for cruise control?

[deesandvees]

Hooking up my cruise control and am wondering where's the best place to hook up the vacuum is? I thought maybe a T on the hose that goes from the intake manifold to the brake booster? The transmission shop originally hooked a T there to operate a Painless vacuum torque converter lockup and it never worked properly so they switched it over to a manual switch.
It's got an Edelbrock carb and a Power Plus intake manifold for small block Chev w/ Vortec heads (http://www.fastpts.com/cgi-bin/hazel...ccyclonevortec) Doesn't look like there's any other vacuum ports on my intake manifold other than the one that goes to the booster. Would there be something on the carb? There's a pinky finger sized plug screwed into the back of the carb and there's a smaller port that's plugged with a rubber plug on the front of the carb.

[j cAT]

Originally Posted by deesandvees

Hooking up my cruise control and am wondering where's the best place to hook up the vacuum is? I thought maybe a T on the hose that goes from the intake manifold to the brake booster? The transmission shop originally hooked a T there to operate a Painless vacuum torque converter lockup and it never worked properly so they switched it over to a manual switch.
It's got an Edelbrock carb and a Power Plus intake manifold for small block Chev w/ Vortec heads (http://www.fastpts.com/cgi-bin/hazel...ccyclonevortec) Doesn't look like there's any other vacuum ports on my intake manifold other than the one that goes to the booster. Would there be something on the carb? There's a pinky finger sized plug screwed into the back of the carb and there's a smaller port that's plugged with a rubber plug on the front of the carb.

the vacuum port at the rear side of intake manifold...between the carb and fire wall top of intake..usually a T connector to connect up this with the other vacuum devices..you need a vacuum ball with a check valve to keep vacuum in the vacuum ball , that then goes to the cruise power head...if not when cruise tries to accelerate up a steep hill it will not work...as the vacuum of engine will drop...with your HP this would probably not be that much of an issue....with 135HP it is....

[deesandvees]

Originally Posted by j cAT

the vacuum port at the rear side of intake manifold...between the carb and fire wall top of intake..usually a T connector to connect up this with the other vacuum devices..you need a vacuum ball with a check valve to keep vacuum in the vacuum ball , that then goes to the cruise power head...if not when cruise tries to accelerate up a steep hill it will not work...as the vacuum of engine will drop...with your HP this would probably not be that much of an issue....with 135HP it is....

Okay so I need to go get a T connector for the manifold. I've got the factory vacuum ball, does it have the check valve inside it or is that something separate? As you can see in the picture below, I've got the small hose going to the vacuum ball and the bigger hose will be going to the T at the manifold.

[j cAT]

the check valve need be installed in the line going to the ball...the use of the vacuum guage should be used to check for proper vacuum in the ball when the vacuum source is removed..this will conferm you have this hooked up in the correct direction..

the ball when vacuum source is removed should hold vac...if not could also be a leak....

[deesandvees]

So I probably have the check valve in my big box of leftovers from when I restored my engine compartment. What does it look like? Anything like the check valve that goes on the brake booster?

[j cAT]

Originally Posted by deesandvees

So I probably have the check valve in my big box of leftovers from when I restored my engine compartment. What does it look like? Anything like the check valve that goes on the brake booster?

usually black one side white or yellow on the other side..obviously on each end you have a 5/32 or 3/16 fitting for hoses..

plastic..

[deesandvees]

Originally Posted by j cAT

usually black one side white or yellow on the other side..obviously on each end you have a 5/32 or 3/16 fitting for hoses..

plastic..

This is all I could find. This a check valve? It's from my donor cruise control.

[j cAT]

that looks good..the funnel shaped side goes to the ball..the T is part of the check valve...you can check by blowing into each end to be sure it has flow only in one direction..

[deesandvees]

Originally Posted by j cAT

that looks good..the funnel shaped side goes to the ball..the T is part of the check valve...you can check by blowing into each end to be sure it has flow only in one direction..

If the check valve only lets air go into the vacuum ball, how does air get out of the vacuum ball? Or does it need to? I wish I had an understanding of how the vacuum works in the cruise control system.

[j cAT]

Originally Posted by deesandvees

If the check valve only lets air go into the vacuum ball, how does air get out of the vacuum ball? Or does it need to? I wish I had an understanding of how the vacuum works in the cruise control system.

vacuum is the absence of air..the check valve stops the vacuum from droping off when the intake vacuum drops due to you putting the pedal to the metal .

If you had the stock engine HP with the cruise on going up a hill WITHOUT THE BALL it could cause the cruise to drop out, and therefore not hold speed as set...

[deesandvees]

Okay that makes sense. I'm still gunna be crossing my fingers on the cruise control test drive.

[j cAT]

Originally Posted by deesandvees

Okay that makes sense. I'm still gunna be crossing my fingers on the cruise control test drive.

to see if its really working gooood....try this. set the cruise for 90 mph, then drop down to 50 mph then resume cruise speed to 90mph..

if it roars up to 90mph then you got it right...I suspect with your power it will...

[deesandvees]

Originally Posted by j cAT

to see if its really working gooood....try this. set the cruise for 90 mph, then drop down to 50 mph then resume cruise speed to 90mph..

if it roars up to 90mph then you got it right...I suspect with your power it will...

When I started this thing up last night (for the first time since last month because I just buttoned up the tv cable situation and leaking master cylinder situation), the diaphragm thing sucked all the way in and stayed in. Is that supposed to happen? I don't have the cruise control cable hooked to the linkage yet (1 step at a time for test drives).

[j cAT]

Originally Posted by deesandvees

When I started this thing up last night (for the first time since last month because I just buttoned up the tv cable situation and leaking master cylinder situation), the diaphragm thing sucked all the way in and stayed in. Is that supposed to happen? I don't have the cruise control cable hooked to the linkage yet (1 step at a time for test drives).

no. did you hook up the electrical to the controlling linkage unit ?
this needs the electrical so that it is allowed to pull on the linkage when vehicle speed drops..below the set speed/also when brakes are on this then also drops out the cruise....the diaphram unit must have a connector socket on it that needs to go to the car wiring connector...

[deesandvees]

Originally Posted by j cAT

no. did you hook up the electrical to the controlling linkage unit ?
this needs the electrical so that it is allowed to pull on the linkage when vehicle speed drops..below the set speed/also when brakes are on this then also drops out the cruise....the diaphram unit must have a connector socket on it that needs to go to the car wiring connector...

Yah I've got the electrical plugged in and the two vacuum lines (and IIRC a ground bolted to the fender).
So what should it do if it was working correctly, the diaphragm would just remain like it is without the car running until you activate the cc?