Ignition System: Description and Operation

Fig. 37 Ignition timing control system.:

This system, Figs. 37, functions similarly to 1983 Prelude models. In addition the distributor has two separate vacuum advance diaphragms. Diaphragm A operates on manifold vacuum. Diaphragm B also operates on manifold vacuum but has a thermovalve in the line. When engine coolant temperature is below the specified temperature of the thermovalve, it sends vacuum to diaphragm B to improve cold engine performance.