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.
1978 Ford FiestaFACTORY OEM SERVICE PROCEDURE
Battery Source Test
- Without disconnecting coil, connect voltmeter between coil "BAT" terminal and engine ground. Connect a jumper wire from coil "DEC" terminal to a known good ground.
- Turn all lights and accessories off and turn ignition on. A voltmeter reading between 4.9-7.9 volts indicates primary circuit from battery to coil is okay.
- If reading is less than 4.9 volts, inspect primary wiring and resistance wire for worn insulation, broken strands and loose or corroded terminals. If reading is greater than 7.9 volts, check and replace resistance wire as necessary.
Factory Service Tools
Use the Manual With the Right Hardware
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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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