Emission Control Maintenance - Chevrolet 1980 Light Duty Truck Service Manual

B-10 Fuel Cap, Fuel Lines and Fuel Tank
(Also an Emission Control Service)
Check the fuel tank, cap and lines for damage or leaks.
Remove fuel cap, check gasket for an even filler neck
imprint, and any damage. Replace parts as needed. Refer
to Section 6C for fuel system repair procedures.
SECTION C
EM ISSIO N CONTROL M A IN TEN A N C E
Refer to Sections 6C or 6E for procedures needed to
service the items below:
C-1 Therm ostatically Controlled Air Cleaner
Check all hoses and ducts for correct hookup. Be sure
valve works properly.
C-2 Carburetor Choke and Hoses
Check that choke and vacuum break work properly.
Correct any binding caused by damage or gum on the choke
shaft. Check hoses for proper hookup, cracks, rubbing,
or decay, correct as needed (Schedule II only).
C-3 Engine Idle Speed
Adjust to the specifications shown on the underhood
label. Use calibrated test equipment.
C-4 Early Fuel Evaporation (EFE) System
Check that valve works properly, correct any binding.
Check that thermal vacuum switch works properly. Check
hoses for cracks, rubbing, or decay. Replace parts as needed.
C-5 Carburetor Mounting
Torque mounting bolts and/or nuts at mileage shown
on Maintenance Schedule.
C-6 Vacuum Advance System and Hoses
Check that system works properly. Check hoses for
proper hookup, cracks, rubbing or decay. Replace parts as
needed.
C-7 Fuel Filter
Replace at mileage shown on Maintenance Schedule or
sooner if clogged.
C-8 PCV System
Check that system works properly each 15,000 miles
(24 000 km) - Light Duty Emission or 12,000 miles (19 200
km) - Heavy Duty Emissions.
PCV Valve and Filter - Replace the valve, filter and
worn or plugged hoses each 30,000 miles (48 000 km) - Light'
Duty Emissions or 24,000 miles (38 400 km) - Heavy Duty
Emissions.
C-9 Spark Plug W ires
Clean wires. Remove corrosion on terminals. Check
the wires for checks, burns, cracks or other damage. Check
the boot fit at distributor cap and spark plugs. Replace wire
if damaged or if corrosion cannot be cleaned.
C-10 Idle Stop Solenoid
Check that parts work properly. Replace them as
needed.
M A IN TEN A N C E AND LUBRICATION
C -11 Spark Plugs
Replace as shown on Schedule. Use the type listed in
Owner's and Driver's Manual.
C-12 Engine Timing and Distributor Cap
Adjust timing to underhood label specifications. Check
the inside and outside of the cap and rotor for cracks, carbon
tracking and corrosion. Clean or replace as needed.
C-13 Carburetor Vacuum Break
(All except light duty emission engine fam ily 08K 4G )
Check that linkage works properly correct any binding.
Check hoses for proper hookup and condition. Replace
parts as needed. If necessary, reset vacuum break as shown
in Section 6C.
C-14 Air Cleaner Element
Replace at mileage shown on Schedule. Replace more
often under dusty conditions.
C-15 Evaporation Control System (ECS)
Check all fuel and vapor lines and hoses for proper
hookup routing and condition. Check that bowl vent and
purge valves work properly, if equipped. Remove canister,
check for cracks or damage. Replace as needed. Replace
canister filter.
C-16 Engine Idle M ixture (4.8L; L6 Only)
At designated intervals or in case of a major carburetor
overhaul, or when poor idle quality exists, adjust mixture
by a mechanical method (lean drop), following the
specifications shown on the label under the hood.
C-17 M anifold Heat Valve
Some engines are equipped with a manifold heat valve
which should be inspected and repaired as necessary to
insure free operation.
C-18 Throttle Return Control (TRC) System
Check hoses for proper connections, cracking,
abrasion, or deterioration and replace as necessary. Check
for proper operation of system.
Check for shorted or broken wires and ensure electrical
connectors are fully engaged at distributor, speed switch and
vacuum solenoid.
C-19 Crankcase Ventilation System
(Diesel Only)
Clean breather cap and filter assemblies (both valve
covers) each 6,000 miles (9 600 km).
Replace breather cap and ventilation regulator valve
assembly each 30,000 miles (48 000 km).
Inspect rubber fittings and replace as required, and
clean tubes each 30,000 miles (48 000 km).
OB-15
LIG H T D U TY T R U CK SERV ICE MANUAL