1991 FORD FESTIVA check engine

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
Page 2 of 3 MITCHELL 1 ARTICLE - GENERAL INFORMATION TROUBLE SHOOTING
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GENERAL INFORMATION
Drive Axle Noise Diagnosis
* PLEASE READ THIS FIRST *
UNRELATED NOISES
Some driveline trouble symptoms are also common to the engine, transmission, wheel bearings, tires and other parts of the vehicle. Make sure
that cause of trouble actually is in the drive axle before adjusting, repairing, or replacing any parts.
NON-DRIVE AXLE NOISES
A few conditions can sound just like drive axle noise and have to be considered in pre-diagnosis. The 4 most common noises are exhaust, tires,
CV/universal joints and trim moldings.
In certain conditions, the pitch of exhaust gases may sound like gear whine. At other times, it may be mistaken for a wheel bearing rumble.
Tires, especially radial and snow tires, can have a high-pitched tread whine or roar, similar to gear noise. Also, some non-standard tires with an
unusual tread construction may emit a roar or whine.
Defective CV/universal joints may cause clicking noises or excessive driveline play that can be improperly diagnosed as drive axle problems.
Trim and moldings can also cause a whistling or whining noise. Ensure that none of these components are causing the noise before
disassembling the drive axle.
GEAR NOISE
A "howling" or "whining" noise from the ring and pinion gear can be caused by an improper gear pattern, gear damage, or improper bearing
preload. It can occur at various speeds and driving conditions, or it can be continuous.
Before disassembling axle to diagnose and correct gear noise, make sure that tires, exhaust, and vehicle trim have been checked as possible
causes.
CHUCKLE
This is a particular rattling noise that sounds like a stick against the spokes of a spinning bicycle wheel. It occurs while decelerating from 40
MPH and usually can be heard until vehicle comes to a complete stop. The frequency varies with the speed of the vehicle.
A chuckle that occurs on the driving phase is usually caused by excessive clearance due to differential gear wear, or by a damaged tooth on the
coast side of the pinion or ring gear. Even a very small tooth nick or a ridge on the edge of a gear tooth is enough to cause the noise.
This condition can be corrected simply by cleaning the gear tooth nick or ridge with a small grinding wheel. If either gear is damaged or scored
badly, the gear set must be replaced. If metal has broken loose, the carrier and housing must be cleaned to remove particles that could cause
damage.
KNOCK
This is very similar to a chuckle, though it may be louder, and occur on acceleration of deceleration. Knock can be caused by a gear tooth that
is damaged on the drive side of the ring and pinion gears. Ring gear bolts that are hitting the carrier casting can cause knock. Knock can also be
due to excessive end play in the axle shafts. NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
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CLUNK
Clunk is a metallic noise heard when an automatic transmission is engaged in Reverse or Drive, or when throttle is applied or released. It is
caused by backlash somewhere in the driveline, but not necessarily in the axle. To determine whether driveline clunk is caused by the axle,
check the total axle backlash as follows:
1. Raise vehicle on a frame or twinpost hoist so that drive wheels are free. Clamp a bar between axle companion flange and a part of the
frame or body so that flange cannot move.
2. On conventional drive axles, lock the left wheel to keep it from turning. On all models, turn the right wheel slowly until it is felt to be in
drive condition. Hold a chalk marker on side of tire about 12" from center of wheel. Turn wheel in the opposite direction until it is again
felt to be in drive condition.
3. Measure the length of the chalk mark, which is the total axle backlash. If backlash is one inch or less, clunk will not be eliminated by
overhauling drive axle.
BEARING WHINE
Bearing whine is a high-pitched sound similar to a whistle. It is usually caused by malfunctioning pinion bearings. Pinion bearings operate at
driveshaft speed. Roller wheel bearings may whine in a similar manner if they run completely dry of lubricant. Bearing noise will occur at all
driving speeds. This distinguishes it from gear whine, which usually comes and goes as speed changes.
BEARING RUMBLE
Bearing rumble sounds like marbles being tumbled. It is usually caused by a malfunctioning wheel bearing. The lower pitch is because the
wheel bearing turns at only about 1/3 of driveshaft speed.
CHATTER ON TURNS
This is a condition where the whole front or rear vibrates when vehicle is moving. The vibration is easily felt and heard. Extra differential
thrust washers installed during axle repair can cause a condition of partial lock-up that creates the chatter.
AXLE SHAFT NOISE
Axle shaft noise is similar to gear noise and pinion bearing whine. Axle shaft bearing noise will normally distinguish itself from gear noise by
occurring in all driving modes. Noise will persist with transmission in neutral while vehicle is moving at problem speed.
If vehicle displays this noise condition, remove suspect axle shafts and replace axle bearings. Re-evaluate vehicle for noise before removing
any internal components.
VIB R AT ION
Vibration is a high-frequency trembling, shaking or grinding condition (felt or heard) that may be constant or variable in level and con occur
during the total operating speed range of the vehicle.
The types of vibrations that can be felt in the vehicle can be divided into 3 main groups:
Vibrations of various unbalanced rotating parts of the vehicle.
Resonance vibrations of the body and frame structures caused by rotating of unbalance parts.
Tip-in moans of resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes. NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00002193
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GENERAL INFORMATION
Clutch Trouble Shooting
* PLEASE READ THIS FIRST *
ALL MODELS
CLUTCH TROUBLE SHOOTING NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
NOTE:This is GENERAL inform ation. This article is not intended to be specific to any unique situation or
individual vehicle configuration. For m odel-specific inform ation see appropriate articles where
available.
Problem & Possible CauseAction
Clutch Chatters/Grabs
Incorrect Pedal AdjustmentAdjust Free Play
Worn Input Shaft SplineReplace Input Shaft
Binding Pressure PlateReplace Pressure Plate
Binding Throw-Out LeverCheck Throw-Out Lever,
Check Throw-Out
Bearing, Check Bearing
Retainer
Uneven Pressure Plate Contact With FlywheelAlign/Replace Worn Parts
Transmission MisalignedAlign Transmission
Worn Pressure PlateReplace Clutch Assembly
Oil-Saturated DiscReplace Clutch Assembly,
Repair Oil Leak
Loose Engine MountsReplace Engine Mounts
Clutch Pedal Sticks Down
Clutch Cable BindingReplace Clutch Cable
Weak Pressure Plate SpringsReplace Clutch Assembly
Binding Clutch LinkageLubricate Linkage
Broken Clutch Pedal Return SpringReplace Return Spring
Clutch Will Not Release
Oil-Saturated DiscReplace Clutch Assembly,
Repair Oil Leak
Defective Disc FaceReplace Clutch Assembly
Disc Sticking on Input Shaft SplinesReplace Disc/Input Shaft
Binding Pilot BearingReplace Pilot Bearing
Faulty Clutch Master CylinderReplace Master Cylinder
Faulty Clutch Slave CylinderReplace Slave Cylinder
Blown Clutch HoseReplace Hose
Sticky Throw-Out Bearing SleeveClean/Lube Sleeve
Clutch Cable BindingReplace Clutch Cable
Broken/Loose BellhousingCheck Bellhousing
Rattling/Squeaking
Broken Throw-Out Lever Return SpringReplace Return Spring
Faulty Throw-Out BearingReplace Throw-Out
Bearing
Faulty Clutch DiscReplace Clutch Disc
Faulty Pilot BearingReplace Pilot Bearing
Worn Throw-Out BearingReplace Throw-Out
Bearing
Dry Bearing Retainer Slide For Throw-Out Bearing SleeveLubricate Slide
Slipping
Faulty Pressure PlateReplace Clutch Assembly
Worn Clutch DiscReplace Clutch Assembly
Incorrect AlignmentRealign Clutch Assembly
Faulty Clutch Slave CylinderReplace Slave Cylinder
No Pedal Pressure
Leaky Hydraulic SystemCheck Clutch Master
Cylinder, Check Clutch
Slave Cylinder
Check Clutch Hose
Broken Clutch CableReplace Clutch Cable
Faulty Throw-Out LeverReplace Throw-Out Lever
Broken Clutch LinkageRepair Clutch Linkage
Page 1 of 2 MITCHELL 1 ARTICLE - GENERAL INFORMATION Clutch Trouble Shooting
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EMISSION CONT ROL VISUAL INSPECT ION PROCEDURES
1983-93 GENERAL INFORMAT ION Em ission Control Visual Inspection Procedures
EMISSION CONTROL LABELS
This article is provided for general information only. Not all information applies to all makes and models. For more complete information, see
appropriate article(s) in the ENGINE PERFORMANCE Section.
The vehicle manufacturer's emission control label, also known as the underhood tune-up label or Vehicle's Underhood Emission Control
System (VECI) label, is located in the engine compartment. Information regarding year model of vehicle, engine size, number of cylinders,
emission equipment or type, engine tune-up specifications, whether vehicle was manufactured for sale in California or is a Federal vehicle,
vacuum hose routing schematic, etc., can be found on this label. See Fig. 1
.
In addition to the VECI label, some emission control inspection and maintenance programs may require an additional label to be affixed to the
vehicle in special circumstances. For example, in California, a Bureau Of Automotive Repair (BAR) engine label may be affixed to the left
door post. A BAR engine label is only used when the vehicle has an engine change, approved modification or is a Specially Constructed
(SPCN) or an acceptable Gray market vehicle. Check your state's emission control inspection and maintenance laws to determine if a simil ar
label is used.

Fig. 1: Typical Emission Control Label

Courtesy of GENERAL MOTORS CORP.
FORD CALIBRATION LABELS
Ford Motor Co. uses an emission calibration label in addition to the emission control label. The emission calibration label is located on either
the engine valve cover, the driver-side door or the left door post pillar.
The calibration label identifies the engine year, calibration design and design revision level. These numbers are also used to identify service
parts and engine specifications that make up the emission system designed for the vehicle. See Fig. 2 , Fig. 3 , Fig. 5 and Fig. 6 .

Fig. 2: Identifying Vehicle Calibration Label (1975
-81 Ford Models)
Courtesy of FORD MOTOR CO.
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Fig. 5: Identifying Vehicle Calibration Label (1989
-93 Ford Models)
Courtesy of FORD MOTOR CO.
EMISSION CONTROL VISUAL INSPECTION
A visual inspection is made to determine if any required emission control devices are missing, modified or disconnected. Missing, mo d ifie d o r
disconnected systems must be made fully operational before a vehicle can be certified.
POSITIVE CRANKCASE VENTILATION (PCV)
PCV controls the flow of crankcase fumes into the intake manifold while preventing gases and flames from traveling in the opposite direction.
PCV is either an open or closed system. See Fig. 4
.
Ensure PCV system is installed as required. Verify valve, required hoses, connections, flame arresters, etc., are present, routed properly and in
serviceable condition.

Fig. 6: Typical Open & Closed Type PCV System

THERMOSTATIC AIR CLEANER (TAC)
The TAC supplies warm air to air intake during cold engine operation. This system is active during cold engine warm-up only. Under all other
operating conditions, air cleaner function is the same as any non-thermostatic unit.
Ensure required exhaust shroud, hot air duct, vacuum hoses and air cleaner components are present and installed properly. See Fig. 7
. Ensure
any required thermostatic vacuum switches are in place and vacuum hoses are installed and in serviceable condition. Also ensure air cleaner
lid is installed right side up. Check for oversized air filter elements and for additional holes in the air cleaner housing.
NOTE:T he following em ission control visual inspection procedures should be used as a guide only. When
perform ing a visual inspection, always follow your state's recom m ended inspection procedures.
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Fig. 7: Typical Thermostatic Air Cleaner System

FUEL EVAPORATIVE SYSTEM (EVAP)
The EVAP system allows for proper fuel system ventilation while preventing fuel vapors from reaching the atmosphere. This means that vapors
must be caught and stored while the engine is off, which is when most fuel evaporation occurs. When the engine is started, these fuel vapors
can be removed from storage and burned. In most systems, storage is provided by an activated charcoal (or carbon) canister. See Fig. 8
. On a
few early systems, charcoal canisters are not used. Instead, fuel vapors are vented into the PCV system and stored inside the crankcase.
The main components of a fuel evaporation system are a sealed fuel tank, a liquid-vapor separator and vent lines to a vapor-storing canister
filled with activated charcoal. The filler cap is normally not vented to the atmosphere, but is fitted with a valve to allow both pressure and
vacuum relief.
Although a few variations do exist between manufacturers, basic operation is the same for all systems. Check for presence of vapor storage
canister or crankcase storage connections when required. Ensure required hoses, solenoids, etc., are present and connected properly. Check
for proper type fuel tank cap. Check for any non-OEM or auxiliary fuel tanks for compliance and the required number of evaporation
canisters.

Fig. 8: Typical Fuel Evaporative System

CATALYTIC CONVERTERS
Oxidation Catalyst (OC)
This type of converter is the most common. It may use pellets or monolith medium, depending upon application. See Fig. 9 . Platinum and
palladium (or platinum alone) are used as catalyst in this type of converter.
Visually check for presence of catalytic converter(s). Check for external damage such as severe dents, removed or damaged heat shields, etc.
Also check for pellets or pieces of converter in the tailpipe.
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Fig. 9: Typical Oxidation Catalytic Converter (Pellet Type) Shown; Typical Three
-Way Catalytic Converter Is Similar
Courtesy of GENERAL MOTORS CORP.
Three-Way Catalyst (TWC)
This type of converter is nearly identical to a conventional converter with the exception of the catalyst. See Fig. 9 . The TWC converter uses
rhodium, with or without platinum, as its catalyst. Rhodium helps reduce NOx emissions, as well as HC and CO.
Visually check for presence of catalytic converter(s). Also check for presence of any required air supply system for the oxidizing section of the
converter. Check for external damage such as severe dents, removed or damaged heat shields, etc. Check for pellets or pieces of converter in
the tailpipe.
Three-Way Catalyst + Oxidation Catalyst (TWC + OC)
This system contains a TWC converter and an OC converter in a common housing, separated by a small air space. See Fig. 10. The 2 catalysts
are referred to as catalyst beds. Exhaust gases pass through the TWC first. The TWC bed performs the same function as it would as a separate
device, reducing all 3 emissions. As exhaust gases leave the bed, they pass through the air space and into the second (OC) converter catalyst
bed.
Visually check for presence of catalytic converter(s). Check for external damage such as severe dents, removed or damaged heat shields, etc.
Check for pellets or pieces of converter in the tailpipe.

Fig. 10: Typical Three
-Way + Oxidation Catalytic Converter
Courtesy of GENERAL MOTORS CORP.
FILL PIPE RESTRICTOR (FR)
A fuel tank fill pipe restrictor is used to prohibit the introduction of leaded fuel into the fuel tank. Unleaded gasoline pump dispensers have a
smaller diameter nozzle to fit fuel tank of vehicle requiring the use of unleaded fuel (vehicles equipped with catalytic converter).
Visually inspect fill pipe restrictor(s) for tampering, i.e., restrictor is oversize or the flapper is non-functional. If vehicle is equipped with an
auxiliary fuel tank, ensure auxiliary fuel tank is also equipped with a fill pipe restrictor.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
Single Diaphragm EGR Valve
This type uses a single diaphragm connected to the valve by a shaft. Diaphragm is spring-loaded to keep valve closed in the absence of
vacuum. As throttle valves open and engine speed increases, vacuum is applied to the EGR vacuum diaphragm, opening the EGR valve. This
vacuum signal comes from a ported vacuum source. Variations in the vacuum signal control the amount of exhaust gas that is recirculated. See
Fig. 11
.
Verify EGR valve is present and not modified or purposely damaged. Ensure thermal vacuum switches, pressure transducers, speed switches,
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