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.
Est System
The ECM monitors information concerning crankshaft position, engine RPM, engine load, atmospheric conditions, engine temperature, and transmission gear position. The information is used to compute the desired spark timing which is relayed to the distributor enabling appropriate changes to ignition timing.
A back-up spark advance system is also incorporated to signal the ignition module in the event of ECM failure.
Distributors on some 4-cylinder equipped engines contain a Hall Effect switch with shutter blades. The Hall Effect switch and shutter blades act as a second pick-up coil and timer core. When the engine is cranking, the pick-up coil and timer core are used to send RPM impulses to the ECM. When the engine is running, the Hall Effect switch and shutter blades perform this function.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.