Manual

Engine Maintenance And Servicing Manual

2.2 Lower body (air system)—description and function of accessories

Excepted that connecting throttle valve to accelerator pedal by a lever, the following parts should be

installed on the lower body.

·throttle valve position sensor

·stepper motor

·hot water loop near the throttle valve and idle air by-pass

·absolute pressure signal port in the lower throttle valve (necessary to be connected with pressure

sensor)

·PCV recirculation pipe

——Throttle valve position sensor “PF2C”.

Figure 140 shows the position sensor case structure, also the relationship between output characteristic,

output signal and throttle valve opening ange.

·Sensor component is consisted of a potentiometer. The slipping ruler of potentiometer is driven directly

by accelerator pedal which is proportional with throttle valve opening.

·the potentiometer is inserted into plastic case with two baffles on the bracket. There are two holes in the

bracket for installing the potentiometer on throttle valve.

· there is spline on the shaft. The spine provides data about throttle position. The data is used to confirm

idle operation condition (accelerator pedal released), full load (accelerator pedal depressed) and accelerating or

Fig.139 temperature sensor and principle

water

Air

Connecting chart

Fig. 140 throttle valve position sensor and operation chart

Ground

Signal output

Power

hrottle valve opening

(angle)