Basic Ignition System Checks (C4): C(3)I: Spark

1991 Cadillac Seville STSSECTION Spark

Disconnect tachometer wire (if equipped). A shorted tachometer will not allow vehicle to start. Disconnect cam sensor and attempt to start engine. If engine starts, see cam sensor trouble code in TESTS W/CODES article.

Check for adequate spark with Spark Tester (ST-125). Check for spark on plug wires No. 1, 3 and 5 (one at a time). Leave matching plug wire connected while checking for spark. When removing spark plug wire from spark plug, twist and pull on boot. DO NOT pull on wire.

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.