Abstract: A filler neck adapter to be inserted through the open fuel mouth of a capless filler neck of a fuel tank of a motor vehicle. The adapter has a hollow flow body to create a continuous flow path between a source of pressure or vacuum and the fuel tank to enable the fuel tank to be tested for leaks. A resilient seal surrounds the flow body of the adapter so as to lie between movable and stationary seal stops. A force-generating member is moved along the flow body to push the movable seal stop and the seal towards the stationary seal stop. Accordingly, the seal is compressed between the movable and stationary seal stops so as to bulge outwardly towards and thereby create an air-tight seal against the fuel mouth of the filler neck.

Abstract: A filler neck adapter to be inserted through the open fuel mouth of a capless filler neck of a fuel tank of a motor vehicle. The adapter has a hollow flow body to create a continuous flow path between a source of pressure or vacuum and the fuel tank to enable the fuel tank to he tested for leaks. A resilient seal surrounds the flow body of the adapter so as to lie between movable and stationary seal stops. A force-generating member is moved along the flow body to push the movable seal, stop and the seal towards the stationary seal stop. Accordingly, the seal is compressed between the movable and stationary seal stops so as to bulge outwardly towards and thereby create an air-tight seal against the fuel mouth of the filler neck.

Abstract: A universal adapter to be detachably connected to the round fuel cap retaining lip of most any fuel tank filler neck so that smoke (i.e., a vapor) under pressure can be delivered to the fuel tank of a motor vehicle to test the fuel system for leaks. When connected, the universal adapter lies entirely outside the fuel tank filler neck. The universal adapter includes a circular ring-shaped rim that is manufactured from a flexible material having a spring memory. The flexible rim of the universal adapter is stretched and attached in surrounding sealing engagement against the fuel cap retaining lip of the filler neck. The universal adapter also includes a vapor inlet tube to which the nozzle of a vapor supply hose is attached. According to one embodiment, smoke produced by a smoke-generating machine pressurizes the fuel tank by way of a vapor delivery path which includes the vapor inlet tube of the universal adapter and the fuel tank filler neck of the motor vehicle.