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Home >> GMC >> 1984 >> Jimmy 5.7 L >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Ignition System - HEI-Est (CALIF) >> Testing >> Intermittent Operation Check
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Intermittent Operation Check

  1. Connect spark tester to 2 different spark plug wires, and crank engine. If no spark, perform Ignition System Check. If spark occurs at either or both wires, check for dwell increase from low to high RPM.
  2. Check pick-up coil. Replace, if faulty. If pick-up coil is good and dwell did not increase, replace HEI-EST module. If good, but dwell increased, check fuel system spark plug wires, distributor cap and plugs.
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