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.
Cold Advance Control Check
The cold advance control (CAC) circuit is designed to advance injection timing about 4° during cold operation. The circuit is activated by a temperature switch through a cold advance control relay to a cold advance solenoid. The switch is calibrated to open the circuit at coolant temperatures above 95°F (35°C).
Below 95°F (35°C), with the ignition switch "on", the cold advance solenoid is continuously energized without the engine running. Below this temperature, with the engine running, a timer in the relay starts to operate and closes the circuit to the cold advance solenoid for 35 seconds. When the solenoid is energized and the engine is running, housing pressure is decreased from 10 psi (69 kPa) to zero which advances the timing 4 degrees.
After 35 seconds, the cold advance solenoid is de-energized and the housing pressure is returned to 10 psi (69 kPa).
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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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