Pontiac tempest 1968 Service Manual page 346

6D-1
EMISSION CONTROL SYSTEMS
CONTENTS O F THIS SECTION
SUBJECT PAGE
Periodic Service Closed PCV System . . . 6 D - 1
Controlled Combustion System 6D-1
Thermostatic Vacuum Switch . . . . . . . 6D-1
SUBJECT PAGE
Auto-Therm A . C . Air Cleaner 6D-1
Motor Replacement . . 6D-1
Sensor Replacement . . . . . . . . . . . . 6D-1
Idle Speeds and Procedure . . . . . . . . . . 6D-2
Dwell and Ignition Timing Specifications . . . 6D-3
PERIODIC SERVICE
CLOSED P.C.V. SYSTEM
Once a year or at 12,000 miles, the Closed Positive
Crankcase Ventilation System should be serviced as
follows:
1. Disconnect all hoses and blow them out with
compressed air. If any hose cannot be freed of ob­
structions, replace with new hose.
2. Remove crankcase ventilation valve.
3. A l l engines are equipped with a crimped-type
valve, thus no further disassembly is possible and a
new valve should be installed.
4. Clean crankcase and intake manifold connectors
using care not to allow dirt to enter openings,
5. Clean and re-oil ventilation filter in air cleaner.
6. Reinstall positive crankcase ventilation system.
7. Adjust carburetor idle to specifications.
CONTROLLED COMBUSTION SYSTEM
In order to provide efficient engine operation of
cars equipped with the Controlled Combustion Sys­
tem, all normal tune-up items should receive careful
and thorough attention every 12 months or 12,000
miles. Adherence to these items will assure that
exhaust emissions are kept to the desired level.
Essential services included in the tune-up items
are:
1. Check engine idle speed.
2. Check ignition timing (both hoses disconnected
and plugged and idle stop solenoid inactive).
3. Check operation of dual acting distributor
advance/retard unit.
NOTE: Engine idle speed must be set following
the correct procedure.
VACUUM ADVANCE VALVE
No adjustments are necessary to the vacuum
advance valve.
THERMOSTATIC VACUUM SWITCH
No maintenance is necessary on the thermostatic
vacuum switch.
AUTO-THERM AC AIR CLEANER
MOTOR R E P L A C E M E N T -
Remove
1. Drill out two spot welds initially with a 1/16"
drill, then enlarge as required to remove the re­
taining strap. Do not damage snorkel tube. (Fig. 6D-1)
2. Raise motor strap retainer.
3. Lift motor, cocking it to one side to unhook
linkage at the control damper.
Install
1. Assemble in reverse order adhering to the
following notes.
a. Drill a 7/64" hole in snorkel tube at point A
as shown in Fig. 6D-1.
b. Use motor strap retainer and sheet metal
screw provided in the motor service package to
secure the retainer and motor to snorkel tube.
c. If screw interferes with operation of the
damper, shorten screw.
SENSOR R E P L A C E M E N T -
Remove
1. Detach hoses at sensor.
2. Pry up tabs of sensor retaining clip.