Chevrolet BEAUVILLE SPORTVAN G10 SERIES, Руководство по обслуживанию

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EMISSION CO N TR O L SYSTEM 6T-9
Vacuum Advance Solenoid
The vacuum advance solenoid is located on the right rear
portio n o f th e inlet m anifold (F ig. 6T -17). This electrically
operated tw o-position plunger con tro lled valve serves to
supply or deny vacuum to the d istrib u to r vacuum advance
unit. In the energized position, th e plunger opens the vacuum
p o rt from the carb u re to r to th e vacuum advance u n it. In
opening the vacuum p o rt th e plunger sim ultaneously closes the
clean air p o rt at th e opposite end. In the de-energized position
the spring loaded plunger seats against th e vacuum inlet and
opens the d istrib u to r advance unit to th e clean air vent.
Time Relay
The tim e relay is a solid state tim ing device designed to
delay circuit co n tin u ity fo r a m inim um o f
20
seconds, after
the transm ission has been shifted in to high forw ard gear.
Delaying circuit com pletion delays vacuum advance. Any
opening o f the transm ission sw itch co n tacts (dow nshift) o f
m ore than one or tw o seconds, causes th e relay to recycle and
deny vacuum advance for an o th er 20 seconds. A transm ission
sw itch in te rru p tio n o f less th a n one second will disable the
tim e relay and prevent vacuum advance u n til th e n ex t u p shift
cycle.
The tim e relay is lo c ate d in th e passenger c o m p artm e n t on
the h o rizo n tal p o rtio n o f th e in stru m e n t panel reinforcem ent
and to the right o f th e steering colum n (Fig. 6T-18).
Temperature Switch
The TCS system te m p eratu re sw itch is located in the right
cylinder head betw een th e n um ber
6
and n um ber
8
exhaust
p o rt (Fig. 6T-19).
T he sw itch is a tw o-position single term inal co n tro l w hich
provides a p a th to ground, for th e cold override feature, w hen
engine coolant tem peratures are below 82 degrees. The “ o f f ’
or “ n e u tra l” position is m ain tain ed at engine coolant tem p er­
atures above 82 degrees.
Fig. 6 T -1 8 —Small V 8 T im e Delay Relay
Fig. 6 T -1 9 —Small V 8 Tem perature Switch (R ig ht Head)
Transmission Switch
On m anual shift synchrom esh transm issions, b o th 3- and
4-speed, th e sw itch is located on th e outside o f the trans­
m ission case in an area adjacent to the 2-3 or 3-4 shifter shaft,
as applicable (Fig. 6T-7). T he m echanically operated sw itch is
spring loaded to provide co n tin u ity betw een the switch te r­
minal and th e sw itch housing. The m olded to p and the plunger
are non-conductors and th erefo re insulate the cup co n tac t and
sw itch term inal w hen th e plunger is depressed. When installed
in the transm ission, th e plunger co n tacts the shifter shaft,
w hich causes th e plunger to retrac t in low forw ard gears. When
the transm ission is shifted in to high forw ard gear, the plunger
drops in to a recess or fla t on the shifter shaft, causing the
plunger to ex te n d an d allow the cup c o n ta c t to rest On the
switch housing (Fig.
6
T-
8
). A circuit is co m pleted to ground,
from the transm ission th ro u g h the sw itch housing to th e cup
c o n tac t and th rough the spring to th e electrical term inal.
The T urbo H ydra-m atic 350 transm issions use a pressure
sensitive sw itch, w hich is activated by transm ission fluid
pressure. The sw itch fo r T u rb o H ydra-m atic is installed ex ter­
nally in the 2-3 direct clutch pressure tap (Fig. 6T-20). A t rest,
in or o u t o f th e installed positio n , the sw itch is in a norm ally
open position. C o n stru ctio n o f the switch is such th at a spring
loaded diaphragm th a t contains a m etallic c o n ta c t, is held
aw ay from a cup c o n ta c t, w hich in tu rn , is in c o n tac t w ith the
sw itch housing (Fig. 6T -10). Transm ission fluid pressure,
against th e insulated plug, forces the diaphragm upw ard so
th a t the diaphragm c o n ta c t closes the circuit th rough the
spring to the electrical term inal.
Fig. 6 T -2 0 —T u rb o H ydra-m atic 3 5 0 Transmission Switch
C H E V Y V A N S H O P M A N U A L