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 Start Valve
The cold start valve is used to provide additional fuel during the crank mode to improve cold start-ups. This circuit is important when engine coolant temperature is low because the other injectors are not pulsed on long enough to provide the needed amount of fuel to start the engine.
The circuit is activated only in the crank mode. The power is supplied directly from the starter solenoid and is protected by a fuse. The system is controlled by a thermal time switch which provides a ground path for the valve during cranking when engine coolant temperature is below 95°F (35°C).
The thermal switch is made of a bi-metallic material which opens at a specified coolant temperature. This bi-metallic material is also heated by the winding in the thermal switch, allowing the valve to stay on for 8 seconds at 68°F (20°C) coolant temperature.
The time the thermal switch will stay closed varies inversely with coolant temperature. As the coolant temperature goes up, the cold start valve "on" time goes down.
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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.