Fig.
4-
l-
13 When coolant temp. rises
[Unloader
system1
If accelerator pedal is depressed for acceleration
while the opening of the choke valve is small,
the throttle lever pulls down the unloader lever
and the choke valve opens up temporarily for
smooth acceleration.
1. Unloader lever
2.
Choke valve
Fig. 4-1-14 Unloader system
Idle Up System
This system operates at idling and compensates
the idle speed;
1) When any one of following electric loads is
operating.
l Small light, tail light, side marker light &
license light
l
Rear defogger (if equipped)
l
Heater fan
2) When car is at a high altitude (higher than
1,220 m (4,000 ft) and HAC is ON).
3) When temperature in engine room is cold
(below 7°C (44°F) and thermal switch is
ON).
4) When engine speed after engine start is lower
than 1,500
r/min.
The ECM sends an electric signal to the Three
Way Solenoid Valve (TWSV). Receiving the
signal, the TWSV opens its inner valve and
transmits the manifold vacuum to the idle-up
diaphragm. As the diaphragm moves down by
the vacuum, the rod move down and push the
throttle lever to open the throttle valve a little
for the idle-up state.
In this way, the idle-up system helps to stabilize
the idle speed even when electric loads operate.
When electric loads stop operating, the TWSV
closes. Then the idle-up diaphragm as well as
rod moves back up, thus the idle-up state is
released.
I
5 1.
2.
3.
4.
5.
8.
7.
8.
Idle-up actuator
Adjusting screw
Diaphragm
Rod
Throttle lever
Throttle valve
Twsv
To intake manifold
Fig.
4-
I-
15 Idle-up system operation
4-11