quadrajet question

[ole blue]

I just bought a 79 seirra grande with a 350 and quadrajet, truck runs great but gets horrible mileage. I cleaned the air filter(k&n) and while it was off I noticed that a larger vacuum outlet(?) at the front of the carb near the top was not connected to anything. I could not find a unconnected vacuum hose anywhere. My question is is supposed to capped off or conected somewhere else.


Thanks
Rod

[zieg85]

Pretty sure you are looking at the vent tube that would go to the charcoal canister.

[JJSZABO]

On mine it goes to the PCV valve and the charcoal cannister

[ole blue]

So it looks like is should go to the pcv valve.   Thanks im gonna check it out... Will it hurt to not go to anything?

Rod

[jefferias]

i have a q-jet as well.   Id say defn hook up your pcv valve should make it run better id think. and if you dont want to hook it up, which i dont reccomend, at leawst plug it off cause your carb will be sucking in un filtered air which is not good. and also put a breather cap where your pcv should be. but again i would just hook it up. hope it helps

[JJSZABO]

I would recommend hooking up the PVC valve also.  At a minimum, you need to do as jefferias suggests if you don't use the PVC valve.

[Captkaos]

You NEED a PCV valve or it will find any weak spot and blow all the oil out of it.  If you are running a breather on the valve cover, you should be ok.