Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1990 Jeep Wrangler Laredo, AutomaticFACTORY OEM SERVICE PROCEDURE
Testing Spark At Coil
- Remove coil wire from distributor cap. Hold end of cable approximately 1/4" from ground. Crank engine and check for spark from coil wire. Spark should be present and constant. If not, check spark plug and coil wire resistance.
- If spark is present and constant, continue cranking engine. Slowly move coil wire away from ground. As coil wire is moved away from ground, check for arching at coil tower. If arching at coil tower is present, replace coil.
- If spark is good and no arching is present, secondary ignition system is producing necessary voltage. Ensure spark reaches spark plugs by checking condition of rotor, cap, spark plug wires and spark plugs. Repair or replace as necessary.
Factory Service Tools
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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.
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