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PCV VALVE DESCRIPTION Is a plastic valve in the engine valve cover (Fig. 6). OPERATION When the engine is not operating or during an engine backfire, the spring forces the plunger back When the engine is at idle or cruising, high mani- fold vacuum is present. At these times manifold vac- During periods of moderate intake manifold vac- uum the plunger is only pulled part way back from DIAGNOSIS AND TESTING - PCV SYSTEM WARNING: APPLY PARKING BRAKE AND/OR BLOCK WHEELS BEFORE PERFORMING ANY TEST (1) With engine idling, remove the hose from the PCV valve. If the valve is not plugged, a hissing (2) Install hose on PCV valve. Remove the make-up air hose from the air plenum at the rear of (3) After allowing approximately one minute for crankcase pressure to reduce, the paper should draw (4) Turn the engine off. Remove the PCV valve from intake manifold. The valve should rattle when (5) Replace the PCV valve and retest the system if it does not operate as described in the preceding t Pipe Sealant With Teflon to the threads. Thread the Fig. 6 PCV System - 2.0L Fig. 7 Engine Off or Engine Backfire No Vapor Flow Fig. 8 High Intake Manifold Vacuum Minimal Vapor Flow Fig. 9 Moderate Intake Manifold Vacuum Maximum Vapor Flow 25 - 16 EVAPORATIVE EMISSIONS PL/SRT-4 |