On the '86 there is a small filter and some "apparatus" behind the passenger headlight that runs the EGR system. I removed all of this when the valve came out. You will find a large black line that heads into the passenger compartment. It's a bit bigger than the others (5mm maybe?). This is a vent line. It has a rubber connection near the firewall by the brake booster. You can separate it at this connection and remove the black line entirely. You don't need to plug the end going into the cabin.