GMC 1982 Light Duty Truck Service Manual page 21

OB-12 MAINTENANCE AND LUBRICATION
B -10 Exhaust G as Recirculation System (EGR)
C O N D U C T E G R O P E R A T I O N system check as
covered in Service M anual. Replace or clean parts as
required.
B -l 1 A ir C lean er and PCV Filter
Replace every 30,000 miles (48 000 km). Replace more
often under dusty conditions. Ask your dealer for the proper
replacement times for your driving conditions.
B - l 2 Early Fuel Evaporation (EFE) System
Check that valve works properly; correct any binding.
Check that thermal vacuum switch works properly.
hoses for cracks, rubbing or decay. Replace parts as needed.
B - l 3 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.
B - l 4 Idle Stop Solenoid a n d /o r Dashpot
C heck th a t parts work properly. R eplace them as
needed.
B - l 5 Fuel Filter
Replace carburetor fuel filter at mileage shown on
Maintenance Schedule or sooner if clogged.
EM IS SIO N CONTROL M A IN TE N A N C E -D IE S E L
B -l Exhaust Pressure Regulator V a lv e
Check that valve works properly. Correct any binding.
Check hoses for cracks, rubbing or decay. Replace parts as
— u
needed.
B-2 Engine Idle Speed
Adjust to the specifications shown on the underhood
label. You must use calibrated test equipment.
B-3 A ir C leaner Elem ent
Replace at 30,000 miles (48 000 km). Replace more
often under dusty conditions. Ask your dealer for the proper
replacement times for your driving conditions.
B-4 Fuel Filters
Replace primary and secondary fuel filters at mileage
shown on Maintenance Schedule or sooner if clogged.