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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 95 (Engine Controls - System/Component Tests - 3.3L Gasoline) >> Emission Systems & Sub-Systems >> Exhaust Gas RECIRCULATION (EGR) >> EGR Gas Flow Test

EGR Gas Flow Test

WARNING: This page is about a different car, the 1995 Plymouth Voyager, 1995 Plymouth Grand Voyager, 1995 Dodge Grand Caravan, and 1995 Dodge Caravan. However, it is still accessible from the selected car via links, so may be relevant.
  1. Warm engine to operating temperature. Disconnect vacuum hose from diaphragm (upper nipple) on EGR valve and attach a hand-held vacuum pump. With engine running, apply 3-5 in Hg. to EGR valve. EGR valve stem should move, and engine should stumble or even stall.
  2. If EGR valve stem moved but idle speed remained steady, EGR valve, EGR tube, intake manifold or exhaust manifold may be plugged with carbon. Remove and clean/replace necessary components.
  3. If EGR valve stem did not move, reapply vacuum to diaphragm and observe vacuum gauge on vacuum pump. If vacuum leaks down, diaphragm is ruptured and EGR valve must be replaced. If vacuum holds and stem does not move, carefully attempt to clean valve. If cleaning does not free stem, replace EGR valve.
NOTE: DO NOT use drills or wires to clean passages for EGR control system. Calibration of precision orifices could be altered, resulting in unsatisfactory vehicle operation.
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