Manual

Engine Maintenance And Servicing Manual
decelerating conditions.
· with absolute pressure sensor out of work, the position sensor will function when working condition
comes back.
·ECU supplies 5V voltage to the variable resistance terminal of throttle valve potentiometer . And
potentiometer output voltage varies with throttle valve position.
·sensor needs not adjustment(through assembling hole), for ECU program may self adjust to minimum
impedance (2°to 14°).
Warning——the following order should be taken during potentiometer replacement:
1. Tighten mounting bolt on the new potentiometer.
2. Turn ignition key to the MAR before connecting line to the potentiometer, and wait for several
minutes.
3. Turn ignition key to stop.
4. Connect wire to the potentiometer’s insert hole.
5. Insert CHECK-UP1 tester. Turn ignition key to CN and erase trouble display.
6. Keep connection until throttle valve position displayed on the screen is 2°～14°. If the parameter
is above 14°, you should check throttle cable and make sure it’s correct (not very tight). Or it needs
to be adjusted again.
Notice: Don’t adjust the potentiometer bolt if it does not return to the specified value of throttle valve
opening angle. The potentiometer should be replaced because it fails.
——Engine idle speed actuator (idle control stepper motor)
Idle control stepper motor is a position actuator of high precision and high distinguishability ( +/-50r/min)
for controlling idle speed.
It is consisted of stepper motor and screw rod-type reduction gear. The reduction gear converts the valve
rotating into linear movement. Stepper motor receives the signal from ECU and makes valve shaft move by
screw rod changing air by-pass passage (see figure 8). Then engine air intake will change during idling. It will
vary with coolant water temperature whether air intake is increasing or decreasing, which keeps speed stable.
Engine minimum idle air intake is set by adjusting throttle valve opening when by-pass channel is closed
completely. Be sure not to touch mixture adjustment bolt. Engine maximum idle air intake is set by valve
returning position, i.e. about 200 steps (8mm travel). The operation steps are the function of engine conditions
(preheating cycle, electrical load, A/C working condition, engine running (hot)).
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