Honda Civic Service Manual: Internal Combustion Powertrain Control

Valve Inspection (R18A9)

1. Fuel Pressure - Relieving (Between the engine and the manual shut-off valve) (Natural Gas Model) Compressed natural gas is flammable ...

Engine Control

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See also:

Honda Civic Service Manual. Heater Unit/Core Removal and Installation (Natural Gas models)
Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat. Be careful when connecting service equipment. ...