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.
Ignition System - HEI-Est: Description
The Delco-Remy High Energy Ignition (HEI) system with Electronic Spark Timing (EST) is a self contained unit. The distributor consists of the housing, rotor, cap, magnetic pick-up, pole piece and pick-up coil. The ignition coil is contained within the cap except for 4-cylinder engines which have an externally mounted coil. The capacitor is used for noise suppression.
All spark timing changes are controlled by the Electronic Control Module (ECM) and there are no vacuum or centrifugal advance mechanisms. Some models use an electronically controlled ignition retard circuit in the event of engine knocking or detonation. Some distributors with externally mounted ignition coils may be equipped with sealed module connectors. See Figure.
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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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