i have a question about fuel lines to tank. there is a plastic valve that has 2 lines that go to metal fuel line towards the front and 1 line that goes to tank on that valve it has a small rubber line on top and larger hose underneath. my question is which direction on the plastic valve with small hose and larger hose goes towards to? the tank or towards the front of van. i think it is called a purge valve. i have a 1990 chevy G20 van with 5.7 liter