Small Vacuum line on 74' from engine compartment to front of car

[Jubbie]

Guys,

There is a small (~0.125" OD) vacuum line that goes into the shift tunnel in the rear of the car near where the fuel lines run in on my 74 911 Targa. I assume this has something to do with the overflow tank or charcoal canister in the front of the car.

My question is what is it and where does it hook up to on the engine. I assume one of the small vacuum ports on the CIS throttle body. The next question is do I need to hook it back up?

Thanks

[buster73]

There are two lines connecting the engine to the "fuel evaporative control system". One line leads from the back of the cooling fan housing to the top of the charcoal cannister (pushes fresh air through the system to purge the charcoal). The second line connects the bottom of the charcoal cannister to the airfilter housing (directs fuel fumes from the canister back into the engine). Unless you remove/plug the whole evaporative system you should reconnect the lines, as otherwise you could get fuel fumes in places you might not like and it could even create a fire hazard. Incorrect connections can also lead to problems with the gas tank venting (smell of gas in the cabin after filling up the gas tank and fuel supply problems).

[Jubbie]

Thanks Guenther,

What are the diameter of thoes hoses and where do they run? All I have found that goes through that center tunnel is the ~1/8" line.

Thanks again.

[buster73]

The line from the fan housing is approx. 1/2 inch. The return line to the air filter housing should be 1/4 inch vacuum line. My car is a 73.5 CIS converted to Webers. but lines are still in place. Guess 74 should be identical.

[Cornerlot]

Originally Posted by Jubbie

Guys,

There is a small (~0.125" OD) vacuum line that goes into the shift tunnel in the rear of the car near where the fuel lines run in on my 74 911 Targa. I assume this has something to do with the overflow tank or charcoal canister in the front of the car.

My question is what is it and where does it hook up to on the engine. I assume one of the small vacuum ports on the CIS throttle body. The next question is do I need to hook it back up?

Thanks

Looks like your question was never answered here. Did you find the real answer? Wondering the same thing on my '77.

[EC900]

tank ventilation-MFI diagrams

[eastbay]