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Home >> Oldsmobile >> 1987 >> Custom Cruiser >> Repair and Diagnosis >> Engine Performance >> Ignition System - HEI-Est >> Testing >> Intermittent Operation Check
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Intermittent Operation Check

  1. Connect Spark Tester (ST-125) to 2 different spark plug wires. If no spark, go to Ignition System Check. If spark is present on either or both wires, check for dwell increase from low to high RPM.
  2. Check pick-up coil and Hall Effect switch (if equipped). Replace if faulty. If pick-up coil and Hall Effect switch are good, and dwell did not increase, replace HEI (EST) module. If pick-up coil and Hall Effect switch are good, and dwell increased, check fuel system, spark plug wires, distributor cap, and spark plugs.
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