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Home >> Ford >> 1979 >> Fiesta >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Exhaust Gas RECIRCULATION (EGR) System - Fiesta >> Testing >> EGR System
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EGR System

  1. Visually examine EGR valve, vacuum hose and stainless steel tube for obvious physical damage. Replace as necessary. Detach vacuum hose from EGR spark port with engine off and cold.
  2. Using a hand-held vacuum pump, apply vacuum to ported vacuum switch. The EGR valve stem should not move. If it does, replace the ported vacuum switch, as switch should be closed.
  3. Start and warm engine to normal operating temperature. Apply vacuum to end of hose at EGR port. EGR valve should open. If not, replace ported vacuum switch.
  4. If system acts as though it is plugged, check lines and connections. Remove EGR valve. Check and clean carbon deposits on EGR valve and passage. If valve requires a lot of cleaning, replace EGR valve.
  5. With engine running at normal operating temperature, slowly open and close throttle, watching for movement of EGR valve stem. If stem does not move, set engine at 2000-2500 RPM. Remove vacuum hose from EGR valve and pinch closed. Engine speed should increase noticeably.
  6. If EGR system still does not respond, return to idle. Remove and plug EGR vacuum hose. Connect another hose between EGR valve and manifold vacuum source. If engine idle drops and becomes rough, replace EGR valve.
  7. Remove EGR gas supply tube. Plug openings at EGR and exhaust manifold. Remove and plug vacuum hose. With engine at normal operating temperature, idle should be smooth and normal. If not, check for leaks at EGR spacer, gaskets, or carburetor. Repair or replace as necessary.
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