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Home >> Buick >> 1987 >> Regal Base, 3.8 7 >> Repair and Diagnosis >> Engine Performance >> System >> 3.8L Feedback Carburetor Tests W/Codes >> Chart C4K - Est Performance Check
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Chart C4K - Est Performance Check

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).
  1. Grounding test terminal causes system to go to a fixed spark advance, which should be different from that obtained with EST operating.
  2. Check timing change with vehicle in Drive. Some engines do not have EST operating in Park/Neutral.
  3. This test checks if fault is in MAP/VAC system.
Fig 1: Chart C4K - EST Performance Check Flow Chart
G6320
Fig 2: Chart C4K - EST Performance Check Flow Chart
GB0046636