Ignition switch FORD FESTIVA 1991 Workshop Manual

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GENERAL INFORMATION
T rouble Shooting - Basic Procedures
* PLEASE READ THIS FIRST *
ACCESSORIES & ELECTRICAL
CHARGING SYSTEM TROUBLE SHOOTING
BASIC CHARGING SYSTEM TROUBLE SHOOTING CHART NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
CONDITION & POSSIBLE CAUSECORRECTION
Vehicle Will Not Start
Dead batteryCheck battery cells, alternator
belt tension and alternator
output
Loose or corroded battery connectionsCheck all charging system
connections
Ignition circuit or switch malfunctionCheck and replace as necessary
Alternator Light Stays On With Engine Running
Loose or worn alternator drive beltCheck alternator drive tension
and condition, See Belt
Adjustment in TUNE-UP article
in the TUNE-UP section
Loose alternator wiring connectionsCheck all charging system
connections
Short in alternator light wiringSee Indicator Warning Lights in
STANDARD INSTRUMENTS
in the ACCESSORIES &
EQUIPMENT section
Defective alternator stator or diodesSee Bench Tests in
ALTERNATOR article
Defective regulatorSee Regulator Check in
ALTERNATOR article
Alternator Light Stays Off With Ignition Switch ON
Blown fuseSee WIRING DIAGRAMS
Defective alternatorSee Testing in ALTERNATOR
article
Defective indicator light bulb or socketSee Indicator Warning Lights in
STANDARD INSTRUMENTS
in the ACCESSORIES &
EQUIPMENT section
Alternator Light Stays OFF With Ignition Switch ON
Short in alternator wiringSee On-Vehicle Tests in
ALTERNATOR article
Defective rectifier bridgeSee Bench Tests in
ALTERNATOR article
Lights or Fuses Burn Out Frequently
Defective alternator wiringSee On-Vehicle Tests in
ALTERNATOR article
Defective regulatorSee Regulator Check in
ALTERNATOR article
Defective batteryCheck and replace as necessary
Ammeter Gauge Shows Discharge
Loose or worn drive beltCheck alternator drive belt
tension and condition. See Belt
Adjustment in TUNE-UP article
in the TUNE-UP section
Defective wiringCheck all wires and wire
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Fig. 2: Ignition Primary Trouble Shooting Chart

STARTER TROUBLE SHOOTING
BASIC STARTER TROUBLE SHOOTING CHART
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
CONDITION & POSSIBLE CAUSECORRECTION
Starter Fails to Operate
Dead battery or bad connections between starter and batteryCheck battery charge and all
wires and connections to
starter
Ignition switch faulty or misadjustedAdjust or replace ignition
switch
Open circuit between starter switch ignition terminal on starter relayCheck and repair wires and
connections as necessary
Starter relay or starter defectiveSee Testing in STARTER
article
Open solenoid pull-in wireTesting in STARTER article
Starter Does Not Operate and Headlights Dim
Weak battery or dead cellCharge or replace battery as
necessary
Loose or corroded battery connectionsCheck that battery connections
are clean and tight
Internal ground in starter windingsSee Testing in STARTER
article
Grounded starter fieldsSee Testing in STARTERS
Armature rubbing on poleSee STARTER article shoes
Starter Turns but Engine Does Not Rotate
Starter clutch slippingSee STARTER article
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Broken clutch housingSee STARTER article
Pinion shaft rusted or drySee STARTER article
Engine basic timing incorrectSee Ignition Timing in TUNE-
UP article
Broken teeth on engine flywheelReplace flywheel and check for
starter pinion gear damage
Starter Will Not Crank Engine
Faulty overrunning clutchSee STARTER article
Broken clutch housingSee STARTER article
Broken flywheel teethReplace flywheel and check for
starter pinion gear damage
Armature shaft sheared or reduction gear teeth strippedSee STARTER article
Weak batteryCharge or replace battery as
necessary
Faulty solenoidSee On-Vehicle Tests in
STARTER article
Poor groundsCheck all ground connections
for tight and clean connections
Ignition switch faulty or misadjustedAdjust or replace ignition
switch as necessary
Starter Cranks Engine Slowly
Battery weak or defectiveCharge or replace battery as
necessary
Engine overheatedSee ENGINE COOLING
SYSTEM article
Engine oil too heavyCheck that proper viscosity oil
is used
Poor battery-to-starter connectionsCheck that all between battery
and starter are clean and tight
Current draw too low or too highSee Bench Tests in STARTER
article
Bent armature, loose pole shoes screws or worn bearingSee STARTER article
Burned solenoid contactsReplace solenoid
Faulty starterReplace starter
S t a r t e r E n ga ge s E n gin e On l y M o me n t a r il y
Engine timing too far advancedSee Ignition Timing in TUNE-
UP article
Overrunning clutch not engaging properlyReplace overrunning clutch.
See STARTER article
Broken starter clutchSee STARTER article
Broken teeth on engine flywheelReplace flywheel and check
starter pinion gear for damage
Weak drive assembly thrust springSee STARTER article
Weak hold-in coilSee Bench Tests in STARTER
article
Starter Drive Will Not Engage
Defective point assemblySee Testing in STARTER
article
Poor point assembly groundSee Testing in STARTER
article
Defective pull-in coilReplace starter solenoid
Starter Relay Does Not Close
Dead batteryCharge or replace battery as
necessary
Faulty wiringCheck all wiring and
connections leading to relay
Neutral safety switch faultyReplace neutral safety switch
Starter relay faultyReplace starter relay
Starter Drive Will Not Disengage
Starter motor loose on mountingsTighten starter attach bolts
Worn drive end bushingSee STARTER article
Damaged engine flywheel teethReplace flywheel and starter
pinion gear for damage
Drive yolk return spring broken or missingReplace return spring
Faulty ignition switchReplace ignition switch
Insufficient clearance between winding leads to solenoid terminal and main contact in solenoidReplace starter solenoid
Starter clutch not disengagingReplace starter clutch
Ignition starter switchReplace ignition switch
contacts sticking
Starter Relay Operates but Solenoid Does Not
Faulty solenoid switch, switch connections or relayCheck all wiring between relay
and solenoid or replace relay
or solenoid as necessary
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Engine overheatingCheck cooling system, See
COOLING
Auto. Trans. pressure regulator valve faultyReplace pressure regulator
va l ve
Auto. Trans. fluid level too lowAdd fluid as necessary
Improper vacuum diverter valve operationReplace vacuum diverter valve
Vacuum leaksInspect vacuum system and
repair as required
Leaking piston ringsReplace piston rings, See
ENGINES
Faulty High Speed Operation
Low fuel pump volumeReplace fuel pump
Le a kin g va l ve s o r wo r nReplace valves and/or springs,
See ENGINES
Incorrect valve timingReset valve timing,See
ENGINES
In t ake man ifo l d rest rict edRemove restriction
Worn distributor shaftReplace distributor
Faulty Acceleration
Improper fuel pump strokeRemove pump and reset pump
stroke
Incorrect ignition timingReset ignition timing, See
TUNE-UP
Le a kin g va l ve sReplace valves, See ENGINES
Worn fuel pump diaphragm or pistonReplace diaphragm or piston
In t ake Backfire
Improper ignition timingReset ignition timing, See
TUNE-UP
Faulty accelerator pump dischargeReplace accelerator pump
Improper choke operationCheck choke and adjust as
required
Defective EGR valveReplace EGR valve
Fuel mixture too leanReset air/fuel mixture, See
TUNE-UP
Choke valve initial clearance too largeReset choke valve initial
clearance
Exhaust Backfire
Vacuum leakInspect and repair vacuum
system
Faulty vacuum diverter valveReplace vacuum diverter valve
Faulty choke operationCheck choke and adjust as
required
Exhaust system leakrepair exhaust system leak
Engine Detonation
Ignition timing too far advancedReset ignition timing, See
TUNE-UP
Faulty ignition systemCheck ignition timing, See
TUNE-UP
Spark plugs loose or faultyRetighten or replace plugs
Fuel delivery system cloggedInspect lines, pump and filter
fo r cl o g
EGR valve inoperativeReplace EGR valve
PCV system inoperativeInspect and/or replace hoses
or valve
Vacuum leaksCheck vacuum system and
repair leaks
Excessive combustion chamber depositsRemove built-up deposits
Leaking, sticking or broken valvesInspect and/or replace valves
External Oil Leakage
Fuel pump improperly seated or worn gasketRemove pump, replace gasket
and seat properly
Oil pan gasket broken or pan bentStraighten pan and replace
ga ske t
Timing chain cover gasket brokenReplace timing chain cover
ga ske t
Rear main oil seal wornReplace rear main oil seal
Oil pan drain plug not seated properlyRemove and reinstall drain
plug
Camshaft bearing drain hole blockedRemove restriction
Oil pressure sending switch leakingRemove and reinstall sending
switch
Excessive Oil Consumption
Worn valve stems or guidesReplace stems or guides, See
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IGNITION SYSTEM TROUBLE SHOOTING
Open coolant temperature sensor circuitTest sensor and wiring
Shorted W.O.T. switch in T.P.S.Disconnect W.O.T. switch,
engine should start
Defective ECMReplace ECM
Fuel tank residual pressure valve leaksTest for fuel pressure drop
after shut down
Hard Starting
Disconnected hot air tube to air cleanerReconnect tube and test
control valve
Defective Idle Air Control (IAC) valveTest valve operation and
circuit
Shorted, open or misadjusted T.P.S.Test and adjust or replace
T.P.S.
EGR valve openTest EGR valve and control
circuit
Poor Oxygen sensor signalTest for shorted or circuit
Incorrect mixture from PCV systemTest PCV for flow, check
sealing of oil filter cap
Poor High Speed Operation
Low fuel pump volumeFaulty pump or restricted fuel
lines or filters
Poor MAP sensor signalTest MAP sensor, vacuum
hose and wiring
Poor Oxygen sensor signalTest for shorted or open
sensor or circuit
Open coolant temperature sensor circuitTest sensor and wiring
Faulty ignition operationCheck wires for cracks or poor
con- nections, test secondary
voltage with oscilloscope
Contaminated fuelTest fuel for water or alcohol
Intermittent ECM groundTest ECM ground connection
for resistance
Restricted air cleanerReplace air cleaner
Restricted exhaust systemTest for exhaust manifold back
pressure
Poor MAF sensor signalCheck leakage between sensor
and manifold
Poor VSS signalIf tester for ALCL hook-up is
available check that VSS
reading matches speedometer
Ping or Knock on Acceleration
Poor Knock sensor signalTest for shorted or open
sensor or circuit
Poor Baro sensor signalTest for shorted or open
sensor or circuit
Improper ignition timingSee VEHICLE EMISSION
CONTROL LABEL (where
applicable)
Check for engine overheating problemsLow coolant, loose belts or
electric cooling fan inoperative
NOTE:For additional electronic fuel injection trouble shooting inform ation, see the appropriate article in the
ENGINE PERFORMANCE section (not all vehicles have Com puter Engine Control articles). Inform ation
is provided there for diagnosing fuel system problem s on vehicles with electronic fuel injection.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
Page 17 of 36 MITCHELL 1 ARTICLE - GENERAL INFORMATION Trouble Shooting - Basic Procedures
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Fig. 4: Ignition Primary Trouble Shooting Chart

STARTER TROUBLE SHOOTING
BASIC STARTER TROUBLE SHOOTING CHART
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
CONDITION & POSSIBLE CAUSECORRECTION
Starter Fails to Operate
Dead battery or bad connections between starter and batteryCheck battery charge and all
wires and connections to
starter
Ignition switch faulty or misadjustedAdjust or replace ignition
switch
Open circuit between starter switch ignition terminal on starter relayCheck and repair wires and
connections as necessary
Starter relay or starter defectiveSee Testing in STARTER
article
Open solenoid pull-in wireSee Testing in STARTER
article
Starter Does Not Operate and Headlights Dim
Weak battery or dead cellCharge or replace battery as
necessary
Loose or corroded battery connectionsCheck that battery
connections are clean and
tight
Internal ground in starter windingsSee Testing in STARTER
article
Grounded starter fieldsSee Testing in STARTERS
Armature rubbing on pole shoesSee STARTER article
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Starter Turns but Engine Does Not Rotate
Starter clutch slippingSee STARTER article
Broken clutch housingSee STARTER article
Pinion shaft rusted or drySee STARTER article
Engine basic timing incorrectSee Ignition Timing in
TUNE-UP article
Broken teeth on engine flywheelReplace flywheel and check
for starter pinion gear damage
Starter Will Not Crank Engine
Faulty overrunning clutchSee STARTER article
Broken clutch housingSee STARTER article
Broken flywheel teethReplace flywheel and check
for starter pinion gear damage
Armature shaft sheared or reduction gear teeth strippedSee STARTER article
Weak batteryCharge or replace battery as
necessary
Faulty solenoidSee On-Vehicle Tests in
STARTER article
Poor groundsCheck all ground connections
for tight and clean
connections
Ignition switch faulty or misadjustedAdjust or replace ignition
switch as necessary
Starter Cranks Engine Slowly
Battery weak or defectiveCharge or replace battery as
necessary
Engine overheatedSee ENGINE COOLING
SYSTEM article
Engine oil too heavyCheck that proper viscosity
oil is used
Poor battery-to-starter connectionsCheck that all between
battery and starter are clean
and tight
Current draw too low or too highSee Bench Tests in
STARTER article
Bent armature, loose pole shoes screws or worn bearingsSee STARTER article
Burned solenoid contactsReplace solenoid
Faulty starterReplace starter
S t a r t e r E n ga ge s E n gin e On l y M o me n t a r il y
Engine timing too far advancedSee Ignition Timing in
TUNE-UP article
Overrunning clutch not engaging properlyReplace overrunning clutch.
See STARTER article
Broken starter clutchSee STARTER article
Broken teeth on engine flywheelReplace flywheel and check
starter pinion gear for damage
Weak drive assembly thrust springSee STARTER article
Weak hold-in coilSee Bench Tests in
STARTER article
Starter Drive Will Not Engage
Defective point assemblySee Testing in STARTER
article
Poor point assembly groundSee Testing in STARTER
article
Defective pull-in coilReplace starter solenoid
Starter Relay Does Not Close
Dead batteryCharge or replace battery as
necessary
Faulty wiringCheck all wiring and
connections leading to relay
Neutral safety switch faultyReplace neutral safety switch
Starter relay faultyReplace starter relay
Starter Drive Will Not Disengage
Starter motor loose on mountingsTighten starter attach bolts
Worn drive end bushingSee STARTER article
Damaged engine flywheel teethReplace flywheel and starter
pinion gear for damage
Drive yolk return spring broken or missingReplace return spring
Faulty ignition switchReplace ignition switch
Insufficient clearance between winding leads to solenoid terminal and main contact in solenoidReplace starter solenoid
Starter clutch not disengagingReplace starter clutch
Ignition starter switch contacts stickingReplace ignition switch
Starter Relay Operates but Solenoid Does Not
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TUNE-UP TROUBLE SHOOTING - GAS ENGINE VEHICLES
BASIC SPARK PLUG TROUBLE SHOOTING CHARTS
Faulty solenoid switch, switch connections or relayCheck all wiring between
relay and solenoid or replace
relay or solenoid as necessary
Broken lead or loose soldered connectionsRepair wire or wire
connections as necessary
Solenoid Plunger Vibrates When Switch is Engaged
Weak batteryCharge or replace battery as
necessary
Solenoid contacts corrodedClean contacts or replace
solenoid
Faulty wiringCheck all wiring leading to
solenoid
Broken connections inside switch coverRepair connections or replace
solenoid
Open hold-in wireReplace solenoid
Low Current Draw
Worn brushes or weakReplace brushes or brush
springs as necessary
High Pitched Whine During Cranking Before Engine Fires but Engine Fires and Cranks Normally
Distance too great between starter pinion and flywheelAlign starter or check that
correct starter and flywheel
are being used
High Pitched Whine After Engine Fires With Key released. Engine Fires and Cranks Normally
Distance too small between starter pinion and flywheelFlywheel runout contributes
to the intermittent nature
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. T he purpose of this T rouble Shooting inform ation is to provide a list
of com m on causes to problem sym ptom s. For m odel-specific T rouble Shooting, refer to SUBJECT ,
DIAGNOST IC, or T EST ING articles available in the section(s) you are accessing.
CONDITION & POSSIBLE CAUSECORRECTION
Normal Spark Plug Condition
Light Tan or Gray depositsNo Action
Electrode not burned or fouledNo Action
Gap tolerance not changedNo Action
Cold Fouling or Carbon Deposits
Overrich air/fuel mixtureAdjust air/fuel mixture, see
ENGINE PERFORMANCE
section
Faulty chokeReplace choke assembly, see
ENGINE PERFORMANCE
section
Clogged air filterClean and/or replace air filter
Incorrect idle speed or dirty carburetorReset idle speed and/ or clean
carburetor
Faulty ignition wiresReplace ignition wiring
Prolonged operation at idleShut engine off during long
idle
Sticking valves or worn valve guide sealsCheck valve train
Wet Fouling or Oil Deposits
Worn rings and pistonsInstall new rings and pistons
Excessive cylinder wearRebore or replace block
Excessive valve guide clearanceWorn or loose bearing
Gap Bridged
Deposits in combustion chamber becoming fused to electrodeClean combustion chamber of
deposits
Blistered Electrode
Engine overheatingCheck cooling system
Wrong type of fuelReplace with correct fuel
Loose spark plugsRetighten spark plugs
Over-advanced ignition timingReset ignition timing see
ENGINE PERFORMANCE
Pre-Ignition or Melted Electrodes
Incorrect type of fuelReplace with correct fuel
Incorrect ignition timingReset ignition timing see
ENGINE PERFORMANCE
Burned valvesReplace valves
Engine OverheatingCheck cooling system
Wrong type of spark plug, too hotReplace with correct spark
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BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS
BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS - USING OSCILLOSCOPE PATTERNS
plug, see ENGINE
PERFORMANCE
Chipped Insulators
Severe detonationCheck for over-advanced
timing or combustion
Improper gapping procedureRe-gap spark plugs
Rust Colored Deposits
Additives in unleaded fuelTry different fuel brand
Water In Combustion Chamber
Blown head gasket or cracked headRepair or replace head or head
ga ske t
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.
CONDITION & POSSIBLE CAUSECORRECTION
Engine Won't Start
Open circuit between distributor and bulkhead connectorRepair circuit
Open circuit between bulkhead connector and ignition switchRepair circuit
Open circuit between ignition switch and starter solenoidRepair circuit
Engine Runs Rough
Fuel lines leaking or cloggedTigh t e n fit t in g, r e mo ve
restriction
Initial timing incorrectReset ignition timing see
ENGINE PERFORMANCE
Centrifugal advance malfunctionRepair distributor advance
Defective spark plugs or wiringReplace plugs or plug wiring
Component Failure
Spark arc-over on cap, rotor or coilReplace cap, rotor or or coil
Defective pick-up coilReplace pick-up coil
Defective ignition coilReplace ignition coil
Defective vacuum unitReplace vacuum unit
Defective control moduleReplace control module
CONDITION & POSSIBLE CAUSECORRECTION
Firing Voltage Lines are the Same, but Abnormally High
Retarded ignition timingReset ignition timing, see
ENGINE PERFORMANCE
section
Fuel mixture too leanReadjust carburetor, see
ENGINE PERFORMANCE
High resistance in coil wireReplace coil wire
Corrosion in coil tower terminalClean and/or replace coil
Corrosion in distributor coil terminalClean and/or replace
distributor cap
Firing Voltage Lines are the Same but Abnormally Low
Fuel mixture too richReadjust carburetor, see
ENGINE PERFORMANCE
Breaks in coil wire causing arcingReplace coil wire
Cracked coil tower causing arcingReplace coil
Low coil outputReplace coil
Low engine compressionDetermine cause and repair
One or More, But Not All Firing Voltage Lines are Higher Than Others
Carburetor idle mixture not balancedReadjust carburetor, see
ENGINE PERFORMANCE
EGR valve stuck openClean and/or replace valve
High resistance in spark plug wiresReplace spark plug wires
Cracked or broken spark plug insulatorReplace spark plugs
Intake vacuum leakRepair leak
Defective spark plugsReplace spark plugs
Corroded spark plug terminalsReplace spark plugs
One or More, But Not All Firing Voltage Lines Are Lower Than Others
Curb idle mixture not balancedReadjust carburetor, see
ENGINE PERFORMANCE
Breaks in plug wiresReplace plug wires causing
arcing
Cracked coil tower causing arcingReplace coil
Low compressionDetermine cause and repair
Defective spark plugsReplace spark plugs
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FUEL INJECTION TROUBLE SHOOTING
Se ve r a l High F ir in g Lin e s
Fuel Mixture UnbalancedCheck Fuel System
EGR Valve Stuck OpenClean/Replace EGR
Valve
High Plug Wire ResistanceReplace Plug Wire
Cracked/Broken PlugsReplace Plugs
Intake Vacuum LeakRepair Leak
Several Low Firing Lines
Fuel Mixture UnbalancedAdjust Fuel Mixture
Plug Wires ArcingReplace Plug Wires
Cracked Coil ArcingReplace Coil
Uneven CompressionCheck/Repair Engine
Faulty Spark PlugsReplace Plugs
Cylinders Not Firing
Cracked Distributor CapReplace Cap
Shorted Plug WiresReplace Plug Wires
Mechanical Engine FaultCheck/Repair Engine
Spark Plugs FouledReplace Plugs
Carbon Track in Distributor CapReplace Cap
Hard Starting
Defective Ignition Coil(s)Replace Coil(s)
Fouled Spark PlugsReplace Plugs
Incorrect TimingReset Ignition Timing
NOTE:T his article is generic in nature and all inform ation does not apply to all vehicles. For vehicle specific
inform ation, see the appropriate articles in the ENGINE PERFORMANCE category.
Problem & Possible CauseAction
Cold Start Valve InoperativeTest Cold Start Valve
Poor Vacuum/Electrical ConnectionRepair Connections
Contaminated FuelTest Fuel for Water/Alcohol
Bad Fuel Pump Relay/CircuitTest Relay/Wiring
Battery Voltage LowCharge/Test Battery
Low Fuel PressureTest Press. Regulator/Pump
No Distributor Reference PulseRepair Ignition System
Coolant Temp. Sensor DefectiveTest Temp. Sensor/Circuit
No Power To InjectorsCheck Injector Fuse/Relay
Hard Starting
Defective Idle Air Control (IAC)Test IAC and Circuit
EGR Valve OpenTest EGR Valve/Control
Circuit
Restricted Fuel LinesInspect/Replace Fuel Lines
Poor MAP Sensor SignalTest MAP Sensor/Circuit
Engine Stalls During Parking ManeuverCheck P.S. Press. Switch
Rough Idle
Dirty Fuel InjectorsClean/Replace Injectors
Poor MAP Sensor SignalTest MAP Sensor/Circuit
Intermittent Fuel Injector OperationCheck Harness Connectors
Erratic Vehicle Speed Sensor InputsHarness Too Close to Plug
Wires
Poor O2 Sensor SignalTest O2 Sensor/Circuit
Faulty PCV SystemCheck PCV Valve and
Hoses
Poor Acceleration
Weak Fuel PumpReplace Fuel Pump
Dirty Fuel InjectorsClean/Replace Injectors
Excessive Intake Valve DepositsClean Intake System
Poor High Speed Operation
Low Fuel Pump VolumeFaulty Fuel Pump/Filter
Poor MAP Sensor SignalTest Speed Sensor/Circuit
Acceleration Ping/Knock
Faulty EGR SystemCheck EGR Valve and
Hoses
Poor Knock Sensor SignalTest Knock Sensor/Circuit
Poor Baro Sensor SignalTest Baro Sensor/Circuit
Improper Ignition TimingAdjust Timing
Engine OverheatingCheck Cooling System
Poor Quality FuelUse Different Fuel
Carbon Build-UpDecarbon Engine
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