Vapor Valve Leak?

Someone probably plugged the vapor vent line up near the missing carbon canister. Normal pumping the tank caused a vacuum which probably collapsed the vapor vent line and caused some of the damage to the seal.

Here is a description of the vapor vent system.
Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel. The canister is normally mounted on the passenger side frame rail near the smog pump pulley.



It does not weigh but a pound or so and helps richen up the cruse mixture. It draws no HP & keeps the car from smelling like gasoline in a closed garage. So with all these good things and no bad ones, why not hook it up & use it?


The purge valve solenoid connector is a dangling wire that is near the ECT sensor and oil filler on the passenger side rocker cover. The actual solenoid valve is down next to the carbon canister. There is about 12"-16" of wire that runs parallel to the canister vent hose that comes off the bottom side of the upper intake manifold. That hose connects one port of the solenoid valve; the other port connects to the carbon canister.

The purge valve solenoid should be available at your local auto parts store.

Purge valve solenoid:



The carbon canister is normally mounted on the passenger side frame rail near the smog pump pulley.
Carbon Canister:

You need some way to vent the tank. It does not have to be a carbon canister, but it does need a vent. With no vent, as gas is pumped out of the tank the volume above the fuel increases. That causes a vacuum to form which will tend to reduce the effectiveness of you fuel pump and can cause vapor lock. If you don't do anything else, either get a vented cap or drill a very small vent hole in your current fuel tank cap.