Positive Crankcase Ventilation (PCV) System Diagnosis

INCORRECT PCV OPERATION:

1. A plugged PCV valve or hose may cause:
a. Rough idle.
b. The engine stalls or idle speed decreases.
c. Oil in air cleaner.

2. A leaking valve or hose can cause:
a. Rough idle.
b. Stalling.
c. High idle speed.

PCV System:

TEST DESCRIPTION:

This test is to see if the PCV System is functioning properly.

1. Check for a correct PCV valve and a properly mounted PCV valve into the rubber grommet. Make sure the hose(s) and clamp(s) are tight, and in place.
2. Start the engine, and let idle.
3. Remove PCV valve from valve cover, and place thumb over valve.
4. Engine rpm should drop, and vacuum should be felt.
5. If no vacuum is present, check for a clogged PCV valve, hose, or intake manifold port.
6. Turn the engine off, and remove the PCV valve from hose. Shake the PCV valve and listen for a rattle. If a rattle was not heard, replace the valve.