99-30-002 GENERAL DIAGNOSTIC PROCEDURES (HARD-TO-FILL FUEL TANK)
All 1999 and later Hyundai vehicles incorporate a new emission control system known as On-Board Refueling Vapor Recovery (ORVR). A general schematic of the system is provided below.
Some owners may experience difficulty filling their vehicle with gasoline and a premature shut off condition as a result of the gas pump nozzles installed at their gas stations. The nozzles at these stations are in the process of being retrofitted or replaced by the nozzle manufacturers. In the meantime, owners should follow instructions posted near the gas pump, and/or try filling the vehicle at a different gas station.
If the refueling difficulty continues, verify that the 1/2" vapor path from the fill vent valve on the gas tank to the air filter on the charcoal canister (see schematic below) is completely
free and clear. To perform the procedure below, make sure the fuel tank is below 1/4 tank full.
To quickly determine the general location of a possible vapor path restriction:
- Disconnect the hose connected to the canister side of the liquid-vapor separator (see schematic below).
- Take the vehicle to a known "good" or major brand gas station.
- If the vehicle readily accepts fuel, the restriction is located between the liquid vapor separator and the air filter.
- If the vehicle does not easily accept fuel, the restriction is located between the liquid vapor separator and the fuel tank.
On-Board Refueling Vapor Recovery (ORVR) Schematic
The following components are contained in the ORVR system:
- Vapor hoses
- Liquid-Vapor Separator(s)
- Fuel Fill Vent Valve
- Fuel Cut Valve (anti-spitback)
- Canister Close Valve
- Air Filter
- Charcoal Canister
After the restriction has been isolated to either half of the system, inspect each component to make sure it is free and clear of any restrictions. Verify that no
back pressure can be felt anywhere between the fill vent valve and the air filter at the canister.
1999 Accents have two (2) liquid vapor separators: one located on top of the fuel tank, the other located alongside the filler neck.
When checking the liquid vapor separator, blow through one end of the pipe using lung power. NO
back pressure should be felt.
Verify that the Fill Vent Valve is open by carefully removing the valve and confirming that the white plastic shut-off plunger moves freely inside its cage.
If the fuel cut valve plunger is stuck closed, a hard-to-fill condition may result. Verify that the plunger moves up and down freely allowing fuel to enter the tank, but does not allow fuel to travel up the neck (under pressure). The plunger should be "up" (closed) in its free state.
When working with the Fill Vent Valve and associated plumbing, be sure to replace the hoses into the proper hose clips to prevent fuel from getting trapped / puddled in the vapor hose. Return fuel from the liquid-vapor separator must have a clear path to drain back to the tank.
Four Way Valve
The Four Way Valve provides an additional vapor path to the canister during refueling.
1999 Sonatas have a Four Way Valve located between the liquid vapor separator and fuel tank.
Proper operation of the valve is as follows:
- Air flows freely in either direction through the 1/2" ports.
Air flows freely in either direction through the 1/4" ports.
- Air flows from 1/2" port to the 1/4" port when blowing into one of the 1/2" ports while plugging the other 1/2" port.
- Air does not flow from 1/4" port to the 1/2" port when blowing into one of the 1/4" ports while plugging the other 1/4" port.
Normal warranty operation codes and times apply.