Testing Precautions

The following precautions MUST be observed during testing procedures:

• DO NOT  ground distributor tachometer connector. Damage to ignition coil or module can result.
• Disconnect ignition switch connector at distributor before making compression checks.
• When using a timing light, attach at plug end of No. 1 spark plug wire. DO NOT  pierce plug boot.
• To 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, plug wire boots, rotor contact button (both sides), rotor and distributor cap. If damaged or worn, replace unit(s).
  2. Verify wiring connector is securely attached to distributor cap. Ensure plug wires are connected at both ends before continuing test procedures.
  3. 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. Intermittent no start condition may be caused by installation of a wrong ignition or pick-up coil.