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 Fuel Cut-Off System
This system cuts off part of fuel flow in idle (or slow) circuit of carburetor preventing overheating and afterburning in exhaust system. The first fuel cut solenoid is kept energized by the ECM whenever engine is running, except when throttle is closed with RPM above 2290. This condition will be sensed by ECM when throttle position switch opens as throttle closes.
With first fuel cut solenoid valve de-energized, the carburetor's slow (or idle) circuit fuel is cut off. This occurs when vehicle is decelerated from 2290 RPM. See Fig 1 and DECELERATION FUEL CUT-OFF SYSTEM OPERATION chart.
Use the Manual With the Right Hardware
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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.