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Home >> GMC >> 1995 >> Forward Control 7.4 N >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (Engine Controls - Basic Diagnostic Procedures - 4.3L) >> C-4, Basic Ignition System Checks >> Enhanced/High Value Ignition System (OBD-II) >> Spark
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Enhanced/High Value Ignition System (OBD-II): Spark

WARNING: This page is about a different variant/trim than selected.
  1. If equipped with factory tachometer, disconnect tachometer terminal before performing tests. To disconnect tachometer lead, it is necessary to disconnect the Gray ignition coil connector from ignition coil. Using a fused jumper wire, jumper connector terminal "B" of ignition coil and Terminal Test Adapter Kit (J 35616-A).
  2. Using Spark Tester (ST-125), crank engine and check for spark at coil wire and at each spark plug wire. If spark is not present or intermittent, go to next step. If spark is present, check spark plugs and fuel system.
  3. Check coil wire or spark plug wire resistance on suspect wire. Resistance should be about 1000 ohms per inch.
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