Testing Precautions

The following precautions MUST be observed during testing procedures:

• DO NOT  ground tachometer terminal of distributor connector. Damage to the electronic module or ignition coil can result.
• Disconnect ignition switch connector at distributor before making compression checks.
• When using a timing light, connect at plug end of number 1 spark plug wire. DO NOT  pierce plug boot.
• Remove spark plug wires, twist boot 1/2 turn and pull on boot (not on wire).
  1. Prior to diagnosis of HEI system, visually inspect spark plug wires, rotor contact button, plug wires boots, rotor and distributor cap for damage.
  2. If a tachometer is connected to the tachometer terminal, disconnect it before proceeding with the test.
  3. Check that wiring connector is properly attached to connector at side of distributor cap, and that spark plug leads are properly connected at both ends before continuing with test procedures.
  4. If engine is difficult to start or misses, check position of battery terminal connector at distributor cap. Terminal must be inserted on side of connector opposite hold-down clip.
  5. Intermittent no start condition may be caused by installation of a wrong pick-up coil or ignition coil.