Throttle Positioner System: Description
The throttle positioner (TP) system controls exhaust emissions during deceleration by holding the throttle plate at an above-idle position during "OFF" throttle operation. This prevents the fuel mixture from being starved of air and helps control HC and CO emissions. The controlling unit is a vacuum-operated TP diaphragm.
The system consists of a throttle positioner diaphragm, vacuum transmitting valve (TVSV), and thermostatic vacuum switching valve.