How to Test an Evap Purge Solenoid

Recently, I made a video on how to test whether the diaphragm in an Evap Purge Solenoid is leaking. My 4.3L in my S-10 pickup was issuing a P0442 diagnostic code to indicate that a small leak was present in the Evap system.

Testing Evap Purge Solenoid video

The purge solenoid is attached to the engine's intake manifold and uses the vacuum from the engine to generate negative pressure inside the Evap system. The amount of vacuum that is able to enter the Evap lines is controlled by...you guessed it: the Evap Purge Solenoid. The other valve/solenoid in the Evap system is the Evap Vent Solenoid (a.k.a. Vent Valve). To distinguish between the two, the vent valve will be located near the Evap Vent Canister which are both located near the fuel tank underneath the bed on most trucks.

Now, I also tested the short plastic line that connects to the purge solenoid. When a vacuum was applied to this line, the vacuum would decay to zero at a moderate rate. Upon closer inspection, I noticed a tear where one section connects at the fitting on the Evap port. Therefore, I used some electric tape as an attempt to seal up the leak. Now, the vacuum decays at a very very slow rate. So far, the check engine light has not come back on with a P0442 diagnostic trouble code (fingers crossed).