Chevrolet 1980 Light Duty Truck Service Manual page 407

a. Inspect carburetor fuel filter for presence of water
and/or impurities. Correct as necessary.
b. Check fuel system for leaks, plugged fuel lines,
incorrect fuel pump pressure and/or plugged carburetor
jets. Correct as necessary.
c. Check ignition timing. Correct as necessary.
d. Check for excessive play in distributor shaft. Repair
or replace as necessary.
e. Check for weak or faulty H.E.I. system coil as
outlined in Section 6D of this manual.
f. Check, inspect and regap spark plugs. Replace as
necessary.
g. Detonation and pre-ignition may be caused by using
sub-standard fuel. Correct as necessary.
h. Check for weak valve springs and condition of
a. Check carburetor for incorrect and/or misadjusted
idle speed, float level, leaking needle and seat, air valve,
sticking choke or enrichment system and secondary vacuum
break operation. Adjust, repair or replace as necessary.
b. Inspect carburetor fuel filter for presence of water
and/or impurities. Correct as necessary.
c. Check H.E.I. system as outlined in Section 6D of this
manual.
d. Check, inspect and regap spark plugs. Replace as
necessary.
e. Check distributor spark advance mechanism for
proper operation. Repair or replace as necessary.
f. Inspect exhaust system for restrictions. Correct as
necessary.
g. Check carburetor mounting gasket for air leaks.
Repair as necessary.
h. Check and adjust valve lash.
a. Check for weak or faulty H.E.I. system coil as
outlined in Section 6D of this manual.
b. Check ignition timing. Correct as necessary.
c. Check for excessive play in distributor shaft. Repair
or replace as necessary.
d. Check, inspect and regap spark plugs. Replace as
necessary.
e. Check carburetor for incorrect and/or misadjusted
idle speed, float level, leaking needle and seat, air valve and
sticking choke or enrichment system. Adjust, repair or
replace as necessary.
ENGINE MISSES AT VARIOUS SPEEDS
ENGINE STALLS
ENGINE HAS LOW POWER
ENGINE M ECH A N IC A L
camshaft lobes. Repair or replace as necessary.
i. Check engine operating temperature. Correct as
necessary.
j. Check operation of exhaust gas recirculation valve.
Repair or replace as necessary.
k. Inspect distributor cap for evidence of carbon
tracking. Replace if necessary.
1. Check for faulty altitude compensator and incorrect
carburetor adjustments. Correct as necessary.
m. Check for vacuum leaks. Correct as necessary.
n. Check operation EFE valve as outlined in Section
6E of this manual. Repair or replace as necessary.
i. Check for burned, warped or sticking valves. Repair
or replace as necessary.
j. Check engine for low compression. Repair as
necessary.
k. Check engine operating temperature. Correct as
necessary.
1. Check for loose, corroded or leaking wiring
connections (bulk-head
necessary.
m. Check operation of exhaust gas recirculation
system. Repair or replace as necessary.
n. Check fuel system for leaks and/or obstructions.
Repair as necessary.
o. Check for vacuum leaks. Correct as necessary.
p. Check operation of EFE valve as outlined in Section
6E of this manual. Repair or replace as necessary.
f. Inspect carburetor fuel filter for presence of water
and/or impurities. Correct as necessary.
g. Check fuel pump for leaks and proper operation.
Correct as necessary.
h. Check for sticking valves, weak valve springs,
incorrect valve timing, lifter noise and worn camshaft lobes.
Adjust, repair or replace as necessary.
i. Check for excessive piston to bore clearance. Correct
as necessary.
j. Check condition of cylinders for uneven compression
and/or blown head gasket. Repair as necessary.
6A-3
connectors, etc.). Repair as
LIG H T T R U CK SER V IC E M AN UAL