Spark Control System: Description
The Spark Timing Control system is designed to control distributor vacuum advance under varying driving conditions to reduce HC and NOx emissions. This is accomplished by the use of a thermal vacuum valve (TVV). In addition, a vacuum delay valve (one-way valve) is used on Pulsar and Sentra.
A vacuum control valve is used on Stanza. A water temperature switch (mounted in the radiator tank), is used on Maxima, 200SX, and 280ZX. A vacuum switching valve (VSV), neutral switch (Man. Trans.), and inhibitor switch (Auto. Trans.) are used on 200SX.