Positive Crankcase Ventilation; Test Performance Of Car - Pontiac Grand Prix Service Manual

TUNE-UP
6C-5
5. Disconnect timing light.
6. Reconnect distributor spark advance hose, then
perform idle speed and mixture adjustment. (See
Section 6D.)
6 Cyl. (4 Bbl.).
...................
.5O BTDC
6 Cyl. (I Bbl.)
.....................
.OO
TDC
V-8.
............................
.9O BTDC
Ram Air IV.
...................
.15O BTDC
IDLE SPEED AND MIXTURE ADJUSTMENT
1. Connect tachometer to engine. Set parking brake.
Start engine, allow to idle.
2. With a thoroughly warmed-up engine, check to see
that choke is fully open and carburetor is on slow idle.
3. Adjust idle speed and mixture screws to give proper
idle speed.
NOTE: Depress or plug hot idle compensator valve
while adjusting all engines so equipped.
Follow procedures outlined in EMISSION CONTROL
SECTION and adjust idle speeds to settings given at
end of that section.
POSITIVE CRANKCASE VENTILATION
All 1969 engines have the closed positive ventilation
systems utilizing manifold vacuum to draw fumes and
contaminating vapors into the combustion chamber
where they are burned. The crankcase ventilation
system has an important function and should be
understood and serviced properly.
In
the closed crankcase ventilation system, air is drawn
through the engine, through a regulating valve and
into the manifold, drawing crankcase vapors and
fumes with it to be burned. The closed positive
ventilation system draws the clean air from the
carburetor air cleaner and has a nonvented oil filler
cap.
The P.C.V. valves are designed specifically for each
engine to control the amount of flow from the
crankcase to manifold. VALVES SHOULD NEVER
BE INTERCHANGED B E M E N 6 AND 8 CYLIN-
DER ENGINES.
The crankcase ventilation valve should be checked at
regular intervals, otherwise it will become plugged and
ineffective.
The P.C.V. system should be serviced at 12,000 miles
or 12 months, as follows:
3. Clean crankcase and intake manifold connectors;
using care not to allow dirt to enter openings.
4. Clean and re-oil ventilation filter in air cleaner.
5. Reinstall Crankcase Ventilation System, using a new
P.C.V. valve.
6. Adjust carburetor idle to specifications, Section 6D.
ROAD TEST
TEST PERFORMANCE OF CAR
Observe performance of engine at low speed, during
acceleration, and at constant speed. Check for missing,
stalling, surging, poor acceleration or flat spots on
acceleration. If any irregularity is found, a complete
diagnosis should be conducted to find and correct
trouble.
TEST OPERATION OF:
BRAKES
-
Pedal should not go closer than 2" from
floor mat (I" with power brakes) and car should not
pull to either side. Fluid level in master cylinder should
be as shown in Fig. 5-4 (Brake Section)..
PARKING BRAKE - Should hold the car without
excessive movement of parkpg brake pedal.
AUTOMATIC TRANSMISSION
-
Observe shift pat-
tern at minimum and full throttle and test forced
downshifts. Watch for any indications of slipping or
unusual shift characteristics that may indicate need for
adjustment.
STEERING GEAR
-
See that steering operates
normally and that steering wheel does not have
excessive play. Also observe for alignment of steering
wheel, pull, wander, or other irregularity that might
indicate need for front end alignment.
WINDSHIELD WIPER - Wiper operation should be
tested with windshield wet in order to properly judge
the action.
CLUTCH
-
See that clutch engages smoothly and that
lash is correct. Follow procedure for adjusting clutch
pedal height and lash in the clutch section. Hard pedal
or lack of pedal return may indicate need for
overcenter spring adjustment.
.
LIGHTS AND HORNS
-
Test operation of headlights,
taillights, stop lights, parking lights, direction signals,
hazard flasher and all other lights, as well as the
horns.
1. D i s c o ~ e c t all hoses and blow them out with
INSTRUMENTS
-
Observe operation of all instru-
compressed air. If any hose cannot be freed of ments. Observe especially for possible abnormal
obstmctions, replace with new hose. reading which may indicate trouble.
2.
Remove
crankcase
ventilation valve assembly from ACCESSORIES
-
Test operation of radio, heater,
rubber grommet, and discard. defroster, cigar lighter, other accessories.