In this video I show a quick and easy way to test to see if an evaporative emissions purge valve is stuck open due to an internal mechanical fault. (The evaporative emissions purge valve is also known as a vapor management valve.)
Step 1: Disconnect the vapor tube going to the valve at the valve. The particular tube that is needed to be disconnected will be the one coming from the evap canister to the purge valve. Typically the evap canister is located near the fuel cell. So this tube will typically run to the rear of the vehicle.
Step 2: Start the engine and allow it to idle. This is important so that vacuum can be applied to the valve. !!! WARNING: BE SURE THE VEHICLE IS IN PARK AND THE PARKING BRAKE IS ON. KEEP THE VEHICLE IN PARK WITH THE PARKING BRAKE APPLIED!!!
Step 3: Disconnect the valve's electrical connector. It is important to do this because the PCM may cause the valve to come on allowing vacuum to pass 0through the valve giving inaccurate test results. It is normal to have the PCM command the valve on. Also, if there is an electrical fault it could cause the valve to stay on allowing vacuum to pass through the valve causing inaccurate test results. A mechanically sound valve should not allow vacuum to pass through it when the valve is not commanded on by the PCM. Disconnecting the valve electrically helps with getting accurate test results by isolating the valve.
Step 4: Place a wet finger over the opening of evap purge valve nipple. No vacuum should be felt. If so, then the valve is stuck open and is faulty. (Do note: in the case of a very small leak, special leak detection equipment may be needed. It's been my experience however, that 99% of the time if the valve is stuck open a leak can be detected in the manner shown in the video.)
Definition of "Normally closed solenoid/valve": A solenoid that is closed when no electrical current is supplied to the valve.
Caution: Keep all ignition sources away from work area. Fuel vapor may be present in tube and valve. Fuel is very flammable. Even with all sources of ignition removed from the area fuel vapor can still ignite via other means. Use extreme caution. Keep a fire extinguisher handy. Work in a well ventilated area. Do test at your own risk!
Caution: Use extreme caution when performing this test. Beware of moving parts that could potentially injure you. Keep your members clear of moving parts. Keep loose garments and jewelry away from moving parts.
Caution: Be sure the vehicle is in park and that the parking brake is applied before performing this test!!
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Barbour's Auto Help is not responsible for any damage or personal injury incurred in the process of performing any auto repairs done by you the viewer. Automotive repair is extremely dangerous. Repair your vehicle at your own risk. It is the viewers responsibility to verify all information and procedures as outlined in YOUR REPAIR MANUAL AND OWNERS MANUAL FOR YOUR VEHICLE. Owning and using a repair manual suited for your vehicle is essential for correctly and safely performing ANY repair to your vehicle. Always wear safety glasses and heed all instructions for use applicable to any piece of equipment you may use. Due to circumstances out of the control of Barbours Auto Help, Barbours Auto Help makes no guarantee that by the use of the information given in this video a quality repair will be made. Barbour'sAutoHelp makes no guarantee that the information provided is totally complete, syncronized and accurate. Verify everything using an appropriate repair manual.
USE THE INFORMATION FOUND IN THIS VIDEO AT YOUR OWN RISK! YOU CAN GET HURT. BE CAREFULL.