Electronic Ignition System: Metro

Ignition system consists of a distributor which uses a signal rotor and pick-up coil/crank angle sensor to produce reference signals to the ECM.

Ignition coil power is provided through 15-amp fuse located in fuse/relay block below left side of instrument panel. Fuse receives power when ignition is turned on. Ground circuit for ignition coil is regulated by the ECM. As rotating signal rotor passes pole piece of pick-up coil/crank angle sensor, a reference signal is sent to ECM. ECM uses this signal to determine when to ground and open primary ignition circuit.

When ECM opens ground circuit for primary ignition, magnetic field around ignition coil windings collapses, producing an induced high voltage surge used to operate the spark plugs.