Coils & Ignition Control Module

RX7 is equipped with a distributorless ignition system that uses 2 crankshaft position sensors, 3 coils and an ignition control module. The coils, one leading and 2 trailing, provide high voltage for spark operation. Crankshaft position sensors detect crank pulley position and send signals to ECM. The ignition control module fires one coil for both leading spark plugs and fires 2 other coils for each trailing spark plug.

Mazda rotary engines use an ignition system with 2 spark plugs in each rotor housing. These fire at different times during ignition cycle. First spark plugs to fire are the leading set, and second spark plugs are the trailing set. Leading set spark plugs fire at about 5 degrees ATDC, depending on ignition advance, to begin combustion. Trailing set spark plugs fire about 20 degrees later to complete combustion.