
Air in fuel system Bleed air from system
Incorrect or contaminated Replace fuel
fuel
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS
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Engines Starts Injection pump timing Reset pump timing, see
and Idles Rough incorrect FUEL SYSTEMS
W/out Smoke or Engine not fully broken in Put more miles on
Noise, But Clears engine
After Warm-Up Air in system Bleed air from system
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS
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Engine Idles Blocked fuel filter Replace fuel filter
Correctly, Injection pump timing Reset pump timing, see
Misfires Above incorrect FUEL SYSTEMS
Idle Incorrect or contaminated Replace fuel
fuel
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Engine Won't Fast idle adjustment Reset fast idle, see
Return To Idle incorrect TUNE-UP
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS
External linkage binding Check linkage and
remove binding
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Fuel Leaks On Loose or broken fuel line Check lines and
Ground connections
Internal injection pump Replace injection pump,
seal leak see FUEL SYSTEMS
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Cylinder Injector nozzles sticking Test injectors, see
Knocking Noise open FUEL SYSTEMS
Very low nozzle opening Test injectors and/or
pressure replace
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Loss of Engine Restricted air intake Remove restriction
Power EGR valve malfunction Replace EGR valve
Blocked or damaged exhaust Remove restriction
system and/or replace
components
Blocked fuel tank filter Replace filter
Restricted fuel filter Remove restriction
and/or replace filter
Block vent in gas cap Remove restriction
and/or replace cap
Tank-to-injection pump fuel Check fuel lines and
supply blocked connections
Blocked fuel return system Remove restriction
Incorrect or contaminated Replace fuel
fuel
Blocked injector nozzles Check nozzle for
blockage, see FUEL
SYSTEMS
Low compression Check valves, rings,
pistons, see ENGINES
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Loud Engine Basic timing incorrect Reset timing, see
Noise With Black FUEL SYSTEMS
Smoke EGR valve malfunction Replace EGR valve
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS

or alcohol
Intermittent ECM ground Test ECM ground
connection for
resistance
Restricted air cleaner Replace air cleaner
Restricted exhaust system Test for exhaust
manifold back
pressure
Poor MAF sensor signal Check leakage
between sensor and
manifold
Poor VSS signal If tester for ALCL
hook-up is available
check that VSS
reading matches
speedometer
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Ping or Knock on Poor Knock sensor signal Test for shorted or
Acceleration open sensor or
circuit
Poor Baro sensor signal Test for shorted or
open sensor or
circuit
Improper ignition timing See VEHICLE EMISSION
CONTROL LABEL (where
applicable)
Check for engine Low coolant, loose
overheating problems belts or electric
cooling fan
inoperative
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NOTE: For additional electronic fuel injection trouble shooting
information, see the appropriate article in the ENGINE
PERFORMANCE section (not all vehicles have Computer Engine
Control articles). Information is provided there for
diagnosing fuel system problems on vehicles with electronic
fuel injection.
IGNITION SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
Ignition Secondary Trouble Shooting Chart
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START: Visually inspect Spark Plug Wires, Coil Wires,
Plug Wire Boots, Rotor, and Distributor Cap for
signs of damage.

Ignition switch faulty Adjust or replace
or misadjusted ignition switch
Open circuit between Check and repair wires
starter switch ignition and connections as
terminal on starter relay necessary
Starter relay or starter See Testing in STARTER
defective article
Open solenoid pull-in See Testing in STARTER
wire article
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Starter Does Not Weak battery or dead Charge or replace
Operate and cell battery as necessary
Headlights Dim
Loose or corroded battery Check that battery
connections connections are clean
and tight
Internal ground in See Testing in STARTER
starter windings article
Grounded starter fields See Testing in STARTERS
Armature rubbing on pole See STARTER article
shoes
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Starter Turns Starter clutch slipping See STARTER article
but Engine
Does Not Rotate
Broken clutch housing See STARTER article
Pinion shaft rusted or See STARTER article
dry
Engine basic timing See Ignition Timing in
incorrect TUNE-UP article
Broken teeth on engine Replace flywheel and
flywheel check for starter pinion
gear damage
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Starter Will Not Faulty overrunning See STARTER article
Crank Engine clutch
Broken clutch housing See STARTER article
Broken flywheel teeth Replace flywheel and
check for starter pinion
gear damage
Armature shaft sheared See STARTER article
or reduction gear teeth
stripped
Weak battery Charge or replace
battery as necessary
Faulty solenoid See On-Vehicle Tests in
STARTER article
Poor grounds Check all ground

connections for
tight and clean
connections
Ignition switch faulty Adjust or replace
or misadjusted ignition switch as
necessary
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Starter Cranks Battery weak or Charge or replace
Engine Slowly defective battery as necessary
Engine overheated See ENGINE COOLING
SYSTEM article
Engine oil too heavy Check that proper
viscosity oil
is used
Poor battery-to-starter Check that all
connections between
battery and starter are
clean and tight
Current draw too low or See Bench Tests in
too high STARTER article
Bent armature, loose pole See STARTER article
shoes screws or worn
bearings
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter
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Starter Engages Engine timing too far See Ignition Timing in
Engine Only advanced TUNE-UP article
Momentarily
Overrunning clutch not Replace overrunning
engaging properly clutch. See STARTER
article
Broken starter clutch See STARTER article
Broken teeth on engine Replace flywheel and
flywheel check starter pinion
gear for damage
Weak drive assembly See STARTER article
thrust spring
Weak hold-in coil See Bench Tests in
STARTER article
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Starter Drive Defective point assembly See Testing in STARTER
Will Not Engage article
Poor point assembly ground See Testing in STARTER
article
Defective pull-in coil Replace starter
solenoid
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Starter Relay Dead battery Charge or replace

Excessive cylinder wear Rebore or replace
block
Excessive valve guide Worn or loose bearing
clearance
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Gap Bridged Deposits in combustion Clean combustion
chamber becoming fused chamber of deposits
to electrode
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Blistered Engine overheating Check cooling system
Electrode
Wrong type of fuel Replace with correct
fuel
Loose spark plugs Retighten spark plugs
Over-advanced ignition Reset ignition timing
timing see ENGINE PERFORMANCE
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Pre-Ignition or Incorrect type of fuel Replace with correct
Melted Electrodes fuel
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
Burned valves Replace valves
Engine Overheating Check cooling system
Wrong type of spark plug, Replace with correct
too hot spark plug, see
ENGINE PERFORMANCE
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Chipped Severe detonation Check for over-
Insulators advanced timing or
combustion
Improper gapping Re-gap spark plugs
procedure
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Rust Colored Additives in unleaded Try different fuel
Deposits fuel brand
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Water In Combus- Blown head gasket or Repair or replace
tion Chamber cracked head head or head gasket
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NOTE: Before diagnosing an electronic ignition system, ensure that
all wiring is connected properly between distributor, wiring
connector and spark plugs. Ignition problem will show up
either as: Engine Will Not Start or Engine Runs Rough.
BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS
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CONDITION POSSIBLE CAUSE CORRECTION \
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Engine Won't Open circuit between Repair circuit
Start distributor and bulkhead
connector
Open circuit between Repair circuit
bulkhead connector and