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.
1987 Jeep Pickup J20FACTORY OEM SERVICE PROCEDURE
Current Flow
- Remove positive and negative wire connectors from ignition coil. Connect ammeter between positive terminal of coil and disconnected positive primary wire.
- Connect jumper wire from negative terminal to good ground. With ignition on, current flow should be approximately 7 amps. Replace ignition coil if current exceeds 7.6 amps.
- With ammeter connected to coil positive terminal, remove jumper wire from negative terminal. Connect coil Green wire to negative terminal. Current flow should be approximately 4 amps.
- If less than 3.5 amps, check for poor contact at 3-wire and 4-wire connectors or distributor ground screw. If current flow is above 5 amps, the control unit is defective and must be replaced. Normal current flow with engine running is 2.0-2.4 amps. Replace control unit if not to specification.
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.