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.
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HOMESERVICE MANUALSCHEVROLET1991CAPRICE WAGON RWD V8-350 5.7LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSELECTRONIC SPARK CONTROL MODULEDESCRIPTION AND OPERATION
1991 Chevrolet Caprice Wagon RWD V8-350 5.7L
Electronic Spark Control Module: Description and Operation
1991 Chevrolet Caprice Wagon RWD V8-350 5.7LSECTION Description and Operation
ESC Wiring Diagram:
The Electronic Spark Control (ESC) system module sends a voltage signal (8 to 10 volts) to the ECM when no spark knocking is detected by the ESC knock sensor, and the ECM provides normal spark advance. When the knock sensor detects spark knock, the module turns "OFF" the circuit to the ECM (0 volts). The ECM then retards EST to reduce spark knock.
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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.