Topic: Vacuum Advance - Common Question These Days....

[dave1987]

Where does it connect? Directly to the intake with the aid of a splitter or to the base of a carburetor?

On my 78, I've always had it connected directly to the intake, but today I drove it from Boise to Meridian with it connected to the base of the carburetor and it ran just fine! I had to bump up the curb idle and make it run a bit more rich, but it doesn't smell like unburnt gas anymore when idling, and actually idles BETTER than it did when connected to the base of the carburetor!

Next question, at idle, should the distributor be advanced AT ALL when idling? When I rev the motor it pulls the arm on the vacuum advance valve that's connected to the distributor, but at idle it stays stationary, is this normal?

I also noticed a little more of a "pinging" sound in the catalytic converter shell now that it is connected to the carburetor base. Not like an engine ping, more like a mis/backfire, and it definitely isn't coming from the motor, it's in the exhaust system.


Below are pictures I took of where I have mine connected to the base of the carburetor right now.

[RSM]

The advance will connect to ported vaccum. You don't want full vaccum to the advance. The way you have it connected is correct. The advance will NOT be pulled all the way at idle. If you rev the engine and watch the vaccum advance it should move in and out. The pinging may be from running too lean now. Something to check is the timing and see where its at. If you have been driving for a while since you changed everything around you should be able to pull a sparkplug out and look at it. If its dark and smells like gas then the engine is rich or it's being lugged around. if its white then thats an indication it may be lean. if it's tan in color then your good. You didnt mention the particulars on the car...automati c or manual tranny...4 cylinder or 6...stuff like that helps a bit.

[dave1987]

It's a 2.3l 4 cylinder with a 4 speed behind it. I'll play with the fuel air mixture when I change the plugs again next week. for now it's running pretty nicely!

[78txpony]

My stock 2.3 has full manifold vacuum going to the disty.  None of the vac hoses have never been changed, and look like they are all going to where they are supposed to.  I have never changed any of it so i wonder if the factory plumbed them up right or not. 
I drew out a vacuum diagram and very little of it matches what the haynes manual portrays. 
Car runs good though...