Table of Contents
Advertisement
8P - 4
SPEED CONTROL
CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
(1) Disconnect the negative battery cable.
(2) Remove speed control cable from throttle cam
by sliding clasp out hole used for throttle cable.
(3) Compress the retaining tabs on the cable and
slide cable out of bracket.
(4) Disconnect electrical connectors and vacuum
hose from servo.
(5) Remove two nuts attaching speed control cable
and mounting bracket to servo.
(6) Pull cable away from servo to expose retaining
clip and remove clip attaching cable to servo.
(7) Remove speed control cable.
INSTALLATION
(1) Slide cable into throttle cable bracket and
engage retaining tabs.
(2) Rotate the throttle cam forward to the wide
open position and install speed control cable clasp.
(3) Rotate the throttle cam forward to the wide
open position and install throttle cable clasp.
(4) Install retaining clip that attaches cable to
servo.
(5) Insert servo studs through holes in the mount-
ing bracket and speed control cable.
(6) Install nuts, tighten to 6.7 N·m (60 in. lbs.).
(7) Connect vacuum hose to servo.
(8) Connect electrical connector.
(9) Install servo and bracket and tighten nuts and
bolt.
(10) Connect negative battery cable.
SERVO
DESCRIPTION
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:
• Vacuum
• Vent
• Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
The PCM controls the solenoid valve body. The
solenoid valve body controls the application and
release of vacuum to the diaphragm of the vacuum
servo. The servo unit cannot be repaired and is ser-
viced only as a complete assembly.
Power is supplied to the servo by the PCM through
the brake switch. The PCM controls the ground path
for the vacuum and vent solenoids.
The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted, the
solenoid dumps vacuum in the servo. This provides a
safety backup to the vent and vacuum solenoids.
The vacuum and vent solenoids must be grounded by
the PCM to operate. When the PCM grounds the vac-
uum servo solenoid, the solenoid allows vacuum to enter
the servo and pull open the throttle plate using the
cable. When the PCM breaks the ground, the solenoid
closes and no more vacuum is allowed to enter the
servo. The PCM also operates the vent solenoid via
ground. The vent solenoid opens and closes a passage to
bleed or hold vacuum in the servo as required.
The PCM cycles the vacuum and vent solenoids to
maintain the set speed, or to accelerate and deceler-
ate the vehicle. To increase throttle opening, the
PCM grounds the vacuum and vent solenoids. To
decrease throttle opening, the PCM removes the
grounds from the vacuum and vent solenoids.
REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect the negative battery cable.
(3) Disconnect the throttle and speed control cable
ends from throttle body (Fig. 2).
Fig. 2 Speed Control Cable End
1 - SPEED CONTROL VACUUM HOSE
2 - THROTTLE BODY
3 - SPEED CONTROL CABLE
RS
Advertisement
Chapters
Table of Contents
