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.
Throttle Control System: Description
Throttle control system is used to reduce Hydrocarbon (HC) emissions during gear shifting and deceleration. Throttle opener diaphragm holds throttle open slightly as necessary to improve combustion.
On Civic 1500 HF models, system consists of dashpot check valve and throttle controller. All other Civic models except CRX Si use a metered orifice to regulate vacuum to throttle controller. On all other carbureted models, system consists of a throttle controller, cranking opener solenoid valve, check valve, and dashpot check valve.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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