Description & Operation
All Honda engines have ignition control systems to lower emission levels, maximize fuel economy and improve engine performance. The system is designed to advance and retard ignition timing as necessary.
Vehicles use a vacuum solenoid valve which is operated by the control unit. Control unit receives signals from intake air temperature sensor and thermosensor. Models with auto. trans. also receive signals from ignition coil, vacuum switch C and speed sensor. When the vacuum control solenoid is open, intake manifold vacuum is allowed to enter the distributor vacuum advance unit.