Vacuum fitting on top of the intake manifold.

What is the little 1/4" vacuum fitting on the rear passenger side of the intake manifold for?

 

There are 2 of them on the intake toward the back, one is for the vacuum on the heater the other is for the vacuum advance of the distributor.

 

Good question. Mine is plugged. I would guess it's for a different (non jeep) application.

 

The heater does use manifold vacuam to operate the controls.I think the distributer uses a port on the carb.(dauntless v-6 w/ 2g rochester.i can't think of anything else that uses manifold vac. on dauntless.
mike starck

 

Where was it at, the carb base. , its been so long since I had a vacuum advance I can't remember. Even got rid of my old distributor about a year ago.

 

The heaters with the push button controls use the one vacuum port. The othe one is ususally pluged.

 

There is only one. Seems like there should be 2.
The vacuum advance goes to the carb base.
I have a vac hose from the heater and one from the wipers.

Bearing on the fact that the heater wires were cut........I don't think it's working. I will eventually work on it though.
I do think I need wipers.........how the hell do they work off of vacuum?
Is it vac alone or is there some sort of motor.....haven't spent any time looking at them but did look a little and saw the little pull knob.

 

If you have vacuum wipers, then you should have a vacuum pump as part of the fuel pump assembly. The manifold vac is routed through the pump to help offset lost vac under heavy throttle conditions. Some folks have replaced the fuel pump with the later non vac style. In this case the vac hose will connect directly to the wiper motors. Personally, I dislike attaching any vacuum appliance to a single runner feed, as a leaking vac motor can cause a lean mix in a single cylinder, which can lead to a burned exhaust valve.

 

You may be right. I probably got it mixed up