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 MANUALSCHEVROLET1993BLAZER FULL SIZE V8-350 5.7LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMRELAYS AND MODULES - IGNITION SYSTEMELECTRONIC SPARK CONTROL MODULEDESCRIPTION AND OPERATION
1993 Chevrolet Blazer Full Size V8-350 5.7L
Electronic Spark Control Module: Description and Operation
1993 Chevrolet Blazer Full Size V8-350 5.7LSECTION Description and Operation
Knock Sensor System
All gas engines are equipped with a knock sensor system. A knock sensor is mounted on the engine block. On vehicles with a manual transmission, the sensor is connected by a blue wire to the knock sensor module, which is bracket mounted on the top of the engine. The sensor, in response to engine knock, sends a signal to the module and from there to the ECM, located in the passenger compartment. The ECM sends a signal to the distributor to retard timing.
If the vehicle is equipped with an automatic transmission (4L80E or 4L60E), a PCM (powertrain control module) is used instead of an ECM. The PCM performs all ECM functions and also provides electronic control for the transmission. It is located in the same place as the ECM.
NO knock sensor module is used on a vehicle equipped with a PCM. Instead, the blue wire from the knock sensor is wired directly to the PCM.
RENDER: 1.0x
NO RELATED
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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.