Hi,

Fairly new C3 1976 owner. Car was running great, but I took the air cleaner assembly off to do some detailing, and now the car seems to be running poorly at start-up. With a cold engine and maybe even after 10 minutes of idle, if i hit the accelerator to hard the engine stalls out. I'm thinking I may have not put the air cleaner assembly back properly or broke something when I was detailing. First question there are two small tubes running from a small green "thing" inside air cleaner (please let me know what this is called, picture attached). One tube runs to the vacuum actuator (which seems a little hard to move without some force) and the other tube runs down towards the carb/engine housing. Which tube connects to which point on the green thing? (see attached). Maybe I reversed them. Any other thoughts? I'm thinking it's getting to much air? or not enough? Thanks.

 

The proper name for this style air cleaner is (TAC) Thermostatic Air Cleaner, the Green valve is simply called Sensor.
Using your top photo, the hose on the right looks to be the longer of the two. The longer hose runs from the sensor to the actuator you describe. The shorter hose connects to the back side of the Quadrajet's throttle plate nipple (THE LOWER NIPPLE), this circuit is full manifold vacuum.
I will try to describe to you how I believe the (TAC) system works when working correctly, at least on my 77 should be the same for your 76.
The normal state (engine off) of the (TAC) actuator damper gate will be open.
On a cold start OR if under hood engine temperature is below 85* the Green sensor will send a vacuum signal to the vacuum actuator closing off the cold air from entering the air cleaner at the damper gate.
After starting the car and as the engine warms up pre-heated air is now entering the air cleaner through the stove pipe tube from the driver side exhaust manifold and is warming up the inside of the air cleaner.
Somewhere between 85*-128* under hood temp. the Green sensor starts to bleed off vacuum (a controlled vacuum leak) causing the actuator to slowly return to its normal state (damper gate open) depending of course on the under hood temperature.
On a restart and the engine is still hot the damper gate may be partially closed but should open quickly.
Make sure the cold air inlet damper gate is open when engine is a Normal operating temp.

 

Does it matter which tube is connected to which side of the sensor? thanks

 

The style and orientation is a little different on my newer old stock sensor but I believe you have the sensor both pointed and vacuum hoses landed correctly.
I honestly don't think it really matters what way the hoses are connected to the sensor.

 

I think you are on the right track. Look and see if all the hoses are connected tightly. Yo may have a slight vacuum leak or you disconnect the choke or disrupted the linkage somehow. Is it hard to start? If any of the hoses go on or come off very easily you may have just broken the seal that age has given to that fitting. You may have to trim off a half inch on the very loose hoses and re attach them