EGR VALVE
- Depress diaphragm with finger to verify smooth operation. With engine running, check if engine idling becomes rough when EGR valve is forced open.
- To test EGR valve for leakage, disconnect valve piping at exhaust manifold. Check if engine idling becomes smooth. If valve leakage is observed, replace EGR valve.
BACKPRESSURE TRANSDUCER
Disconnect backpressure transducer hoses. Blow air into Black colored hose on valve. Check that air passes through valve (closed valve) by blowing air into EGR side of valve. Air should travel to opposite side of valve.
THERMAL VACUUM VALVE
Disconnect hoses from opposite side of valve. Blow through hoses connected to valve. Check that no continuity exists between hoses when engine is cold and that valve opens when engine is warmed to 122°F (50°C).
Turbo Only
Ensure that engine is cold and that idle and WOT switches are off. Disconnect hoses from opposite side of valve. Blow through hoses connected to valve. Check that no continuity exists between hoses when engine is cold and that valve opens when engine is warmed to 122°F (50°C).