Description & Operation

All Honda models utilize ignition control systems designed to lower emission levels, maximize fuel economy and improve engine performance. Ignition timing on fuel injected models is controlled by the Electronic Control Unit (ECU) based upon sensor input signals.

All carbureted models and Accord fuel injected models use a distributor advance with 2 separate vacuum diaphragms. Diaphragm A operates on intake manifold vacuum. Diaphragm B operates on intake manifold vacuum regulated by an in-line thermovalve or ECU controlled solenoid (fuel injected Accord). During cold engine operation, thermovalve or solenoid allows vacuum to enter diaphragm B, advancing timing to improve cold engine performance.