Fuel Line Question

[RQ-B1899]

I am the owner of a 1972 Avanti II with a factory four speed and I am doing some cleaning and detailing

underneath the car. I have a couple of questions. It appears that I have 3 fuel lines running back to the

gas tank and I am not sure what the function of that many lines would be. I would also like to know if my

car has flanged axles.

Thank you very much for sharing your knowledge.

[Gunslinger]

I can't say for sure, but two fuel lines are probably a feed line and a return line. Are you sure the 3rd line isn't a brake line? Maybe at some point someone replaced an original fuel line by simply bypassing it with a new one. During the '70s with emissions controls being added all the time, who knows what was added. Check your fuel pump and see if it has two lines running to the rear of the car...feed and return. A possibility is there's a charcoal cannister line for filtering or absorbing fumes. We all know Avanti Motors did a lot of adapting to meet the increasing government requirements in a car body and chassis not designed originally for such things.

Yes...your car should have flanged axles.

[Ray K.]

I am the owner of a 1972 Avanti II with a factory four speed and I am doing some cleaning and detailing

underneath the car. I have a couple of questions. It appears that I have 3 fuel lines running back to the

gas tank and I am not sure what the function of that many lines would be. I would also like to know if my

car has flanged axles.

Thank you very much for sharing your knowledge.

I am not an expert. but it seems to me that 1972 was a bit early for the "3-line" fuel delivery system. I agree that one line was for delivery, one for return, and one for gasoline fume capture by an under-hood charcoal canister. But, since catalytic converters themselves were not required until 1973. it is a mystery to me why a 1972 car would have an unvented gas tank.

[Gunslinger]

Corvettes had charcoal cannisters installed beginning in 1970. The cannisters were also mounted at the gas tank in the rear of the car, so it's plausible a '72 Avanti could have a similar installation. The best way to check would be to take the back seat out and the panel between the passenger compartment and the gas tank and see if there is a charcoal cannister back in there.

[adamderosa]

I have 3 fuel lines on my '72 also. One is fuel feed to the pump, one is fuel return from the filter, and one is fuel vapor from the charcoal cannister.

[RQ-B1899]

Thanks for all of the great information.

I really appreciate your taking the time to answer my questions.

I'm sure I'll be asking more later.