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.
Deceleration Control System: Description
Deceleration systems reduce HC emissions through the use various devices. On Colt and Colt Vista models a dashpot and a deceleration spark advance system consisting of an engine speed sensor and solenoid valve is used. On Ram-50 Pickups, air switching valve, coasting air valve and dashpot (all Man. Trans. models except Federal Pickups) are used.
Air switching valve cuts off fuel to by-pass holes and pilot outlet by supplying additional air to slow idle passage. Coasting air valve supplies additional air to intake manifold. Deceleration spark advance system advances ignition timing by changing vacuum supplied to valve from carburetor ported intake vacuum to intake manifold vacuum.
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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.