Ignition System: Description and Operation

Electronic Spark Timing (Turbo):

Electronic Spark Timing (EST) is ECM controlled. The ECM monitors information from various sensors, computes the desirable spark timing and signals the distributor when timing changes are required. The distributor does not contain centrifugal advance weights, springs or a vacuum advance unit. Base timing is adjustable. If it is not correctly set, the entire spark advance curve will be off. The ECM utilizes information from the MAP, coolant temperature and knock sensors and engine rpm to calculate spark advance.