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 MANUALSCHEVROLET1985C 20 P/U 2WD V8-350 5.7LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTEMISSION CONTROL SYSTEMSEARLY FUEL EVAPORATION ( EFE )TESTING AND INSPECTION
1985 Chevrolet C 20 P/U 2WD V8-350 5.7L
Early Fuel Evaporation ( EFE ): Testing and Inspection
1985 Chevrolet C 20 P/U 2WD V8-350 5.7LSECTION Testing and Inspection
Chart C-9C - EFE System Check - With TVS:
Vacuum Diagram for Chart C-9C - EFE System Check - With TVS:
CHART C-9C - EFE SYSTEM CHECK - WITH TVS
Test Description:
1. Engine coolant temperature should be below 40~C (105~F).
2. EFE valve should open above 40~C (105~F).
3. There should be at least 34 kPa (10" Hg.) vacuum available to EFE actuator diaphragm.
4. Valve may be seized up. It may be freed up by using heat valve lubricant (part # 1052627 or equivalent). If valve does not free up, it must be replaced.
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.