GMC 1986 P-Truck Service Manual page 35

13. SPARK PLUGS * — Replace spark plugs with the type listed in
your Owner's Manual.
— Clean wires and inspect for burns, cracks
14. WIRE SERVICE *
or other damage. Check the wire boot fit at the distributor and at
the spark plugs. Replace wires as needed.
15. EGR SYSTEM CHECK * — Conduct EGR SYSTEM CHECK.
Refer to DRIVEABILITY AND EMISSIONS (SEC. 6E8).
16. ENGINE TIMING CHECK AND DISTRIBUTOR CHECK (SOME
MODELS)* — Adjust timing to underhood label specifications.
Inspect the inside and outside of the distributor cap and rotor for
cracks, carbon tracking and corrosion. Clean or replace as
needed.
17.
FUEL TANK, CAP AND LINES INSPECTION
fuel tank, cap and lines for damage or leaks. Remove fuel cap,
inspect gasket for an even filler neck imprint, and any damage.
Replace parts as needed.
18. EARLY FUEL EVAPORATION (EFE) SYSTEM INSPECTION *
— Check that valve works properly; correct any binding. Check
that thermal vacuum switch works properly. Check hoses for
cracks, chafing, or decay. Replace parts as needed.
19 THERMOSTATICALLY CONTROLLED AIR CLEANER IN-
— Inspect all hoses and ducts for proper
SPECTION * A
hookup. Make sure valve works properly.
20. ENGINE ACCESSORY DRIVE BELTS INSPECTION
spect belts. Look for cracks, fraying, wear, and proper tension.
Adjust or replace as needed.
21. EVAPORATE CONTROL SYSTEM (ECS) INSPECTION * —
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, and check for
cracks or damage. Replace as needed.
22. SHIELDS AND UNDERHOOD INSULATION INSPECTION
— Inspect shields and underhood insulation for damage or
looseness. Adjust or replace as required.
23. AIR INTAKE SYSTEM INSPECTION
take system installation to see that gaskets are seated properly
and all hose connections, fasteners, and other components are
* An Emission Control Service
AAlso a Noise Emission Control Service
■ Applicable only to vehicles sold in the United States
14
tight. Also check to be sure that the air cleaner housing is prop­
erly seated on the carburetor, that the cover fits tightly, and the
wingnut is tight. Tighten connections and fasteners or replace
damaged parts as required.
24.
THERMOSTATICALLY CONTROLLED ENGINE COOLING
FAN CHECK A
below normal operating temperature, check to see that the fan
can be rotated by hand on fluid coupling or viscous drives. Re­
place as necessary.
25
MANIFOLD HEAT VALVE CHECKA
equipped with a manifold heat valve which should be inspected
and repaired as necessary to insure free operation.
* — Inspect the
26. IDLE STOP SOLENOID AND/OR DASHPOT CHECK * —
Check that parts work properly. Replace them as needed.
27 THROTTLE RETURN CONTROL (TRC) SYSTEM CHECK * —
Check hoses for proper connections, cracking, abrasion, or de­
terioration and replace as necessary. Check for proper operation
of system. Check for shorted or broken wires and ensure electri­
cal connectors are fully engaged at distributor, speed switch and
vacuum solenoid.
28.
ENGINE IDLE MIXTURE ADJUSTMENT (4.8 L ONLY)
designated intervals or in case of a major carburetor overhaul, or
when poor idle quality exists, adjust mixture by a mechanical
* — In­
method (lean drop), following the specifications shown on the
label under the hood.
29. GOVERNOR CHECK A
no-load governed speed and reset to specifications as required.
30. EXHAUST PRESSURE REGULATOR VALVE INSPECTION
— Check that valve works properly. Correct any binding. Check
hoses for cracks, chafing or decay. Replace parts as needed.
* An Emission Control Service
AAlso a Noise Emission Control Service
■ Applicable only to vehicles sold in the United States
▲ ■ — Check the air in­
■ — (If so equipped.) With the
engine off
■ — Some engines are
■ — (If so equipped). Check the engine
15
and
* — At
*