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 System
The cold start system provides additional air and fuel during cold engine starts. The cold start system consists of an auxiliary air valve which provides additional air, cold start injector which delivers additional fuel, and a thermo time switch which controls operation of the cold start system.
The thermo time switch has a bi-metallic contact surrounded by a heating coil which is energized during engine cranking. This switch limits cold start system to 8 seconds under extreme cold engine starts in relation to engine coolant temperature. When coolant temperature is above 95°F (35°C), bi-metallic contact breaks ground circuit of cold start injector and cold start enrichment is by-passed.
The auxiliary air valve provides additional air during cold engine starts and warm-up period. The valve consists of an electrically heated bi-metallic strip, movable disc and air by-pass channel.
The heater coil on the bi-metallic strip is energized by the fuel pump relay. Control of the valve is based upon engine temperature. The air by-pass channel is open when engine is cold and gradually closes as temperature rises. At predetermined temperatures, air by-pass channel is blocked and additional air flow stops. See Fig 1 .
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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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