EGR VALVE
- Disconnect vacuum hose from EGR valve and connect outside vacuum source, such as hand pump with gauge. Apply about 4 in. Hg and hold this level. Vacuum should not leak down.
- While applying vacuum, watch movement of valve stem. At 4.7 in. Hg (Fed. Man. Trans.) or 3.9 in. Hg (all others), stem should move diaphragm to full up position. If valve does not respond as indicated, replace EGR valve.
BACKPRESSURE TRANSDUCER
Apply a pressure above 0.07 psi (0.005 kg/cm 2 ) to port connected to backpressure signal pipe and check transducer for leaks. If leaks are noted, replace transducer as an assembly.
THERMAL VACUUM VALVE
Remove thermal vacuum valve from engine and place sensing portion in water. Water should be at 115-129°F (46-54°C) for automatic transmission equipped vehicles or 113-131°F (45-55°C) for manual transmission equipped vehicles. Blow through hoses connected to valve. Air should pass, indicating valve is open. If not, replace valve.