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Home >> Nissan-Datsun >> 1990 >> Sentra Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/O Codes >> Unstable Idling >> Before Warm-Up
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Before Warm-Up

  1. Ensure ignition timing is within specification.
  2. Check fast idle cam.
  3. If Equipped: Perform AIR REGULATOR diagnostic chart in SYSTEM/COMP TESTS article. Use DIAGNOSTIC CHARTS DIRECTORY table in SYSTEM/COMP TESTS article to locate chart.
  4. Remove vacuum hose from fuel pressure regulator. Apply vacuum and pressure and monitor symptom change.
  5. Check idle speed control circuit. See IDLE CONTROL SYSTEM in SYSTEM/COMP TESTS article.
  6. Check EGR control valve operation.
  7. Check EGR control valve solenoid operation.
  8. Enter self-diagnostic Mode III and retrieve codes. If vehicle will not start, crank engine before entering self-diagnostic Mode III.
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