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Home >> GMC >> 1987 >> Safari Van M L4-151 2.5L >> Repair and Diagnosis >> Powertrain Management >> Emission Control Systems >> Exhaust Gas Recirculation >> EGR Valve >> Testing and Inspection >> Ported Vacuum EGR Valve
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Ported Vacuum EGR Valve


1. Place finger under EGR valve and push on diaphragm plate. Diaphragm should move freely from open to closed position. If it does not move freely, replace valve. Do not touch the valve when engine is hot.
2. Connect a vacuum gauge between EGR signal tube and vacuum hose.
3. With transmission in Park or Neutral and engine running, open throttle to obtain 5 inches Hg at EGR valve.
4. Remove vacuum hose from EGR signal tube and check for diaphragm plate to move downward (valve closed). If diaphragm does not move, increase engine speed. If diaphragm still does not move, replace EGR valve.
5. Connect vacuum hose and check for diaphragm plate to move upward (valve open). If diaphragm does not move increase engine speed. If diaphragm still does not move, replace EGR valve. A vibration of the diaphragm plate may be noticed. This does not indicate a bad valve or require correction.



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