Intermittent Simulation
To reproduce the conditions creating an intermittent fault, use the following methods
- Lightly vibrate component.
- Heat component.
- Wiggle or bend wiring harness.
- Spray component with water.
- Remove/apply vacuum source.
Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. See appropriate TESTS W/CODES article in the ENGINE PERFORMANCE Section. Use test results to identify a faulty component or circuit.
Note. For test equipment connection and CONTINUOUS MONITOR MODE test operation, see TESTS W/CODES article in the ENGINE PERFORMANCE Section.
CHART 1-NO CRANK
| System & Component(s) | Reference |
|---|---|
| STARTING Battery Starter Relay Starter Neutral Drive Switch/Clutch Switch Brake Interlock Switch Ignition Switch Transmission Linkage Adjustment | Charge or replace battery. Check charging and starting systems. |
| EEC Neutral Drive Switch/Clutch Switch | See TESTS W/CODES article. |
| BASE ENGINE Flywheel | Check engine mechanical condition. |
| FUEL/THROTTLE BODY Injectors (hydro-lock) | See FUEL SYSTEM in I - SYS/ COMP TESTS article. |
| IGNITION Harness (START Wire Short to Ground) | See I - SYS/COMP TESTS article |
DIAGNOSTIC CHART 1-NO CRANK
CHART 2-CRANKS NORMALLY BUT SLOW TO START
| System & Component(s) | Reference |
|---|---|
| IGNITION All Types: Scope engine for: Spark Plugs, Coil, Secondary Ignition Wires, Spark Plugs Fouled TFI IV: Distributor Cap, Adapter and Rotor DIS/EDIS: Single or Dual Hall Crank- shaft Sensors, Hall Cam- shaft Sensor, DIS/EDIS Ignition Module, Coil Pack | See IGNITION SYSTEMS in I - SYS/ COMP TESTS article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Filter Pump Water/Dirt/Rust Contamina- tion in Fuel Fuel Lines Fuel Pressure Regulator Sender Filter Injectors Improper Fuel Idle Airflow | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| EXHAUST Component (Restricted) | Inspect exhaust system. |
| AIR INTAKE & VACUUM DISTRIBUTION Vacuum Leaks Air Cleaner Element Restricted | Perform visual & audible inspection. |
| COOLING Electric Fan (Hot Start Only) | Check cooling system. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| PCV Valve | See I - SYS/COMP TESTS article. |
| EVAP Valve | See I - SYS/COMP TESTS article. |
DIAGNOSTIC CHART 2-CRANKS NORMALLY BUT SLOW TO START
CHART 3-CRANKS NORMALLY BUT WON'T RUN (STALLS)
| System & Component(s) | Reference |
|---|---|
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Idle Airflow Electrical & Vacuum Com- ponents Fuel Filter Fuel Pump Water/Dirt/Rust Contamina- tion in Fuel Fuel Lines Tank (Fuel Supply) Sender Filter Fuel Pressure Regulator Injectors Improper Fuel | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection |
| IGNITION All Models: Electrical Connections Secondary Ignition Wires Ignition Switch TFI IV: Ignition Coil Ignition Module Rotor Alignment Distributor Cap, Adapter, Rotor and Stator Ballast Resistor DIS (Thunderbird SC only): Hall Camshaft Sensor (CD) | See IGNITION SYSTEMS in I - SYS/ COMP TESTS article. |
| EXHAUST Component (Restricted) | Inspect exhaust system. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| AIR INTAKE SYSTEM Air Tube Intercooler Tube (Thunderbird SC only) | Check connections. |
| BASE ENGINE Camshaft and Valve Train. | Check engine mechanical condition. |
DIAGNOSTIC CHART 3-CRANKS NORMALLY BUT WON'T RUN (STALLS)
CHART 4-CRANKS NORMALLY BUT WON'T START
Note. Extended cranking, due to no-start condition, can load the exhaust system with raw fuel, which can ruin the catalytic converter after the engine is started. After servicing no-start condition, disconnect the thermactor air supply, operate engine until surplus fuel is used up, and then reconnect the thermactor air supply.
| System & Component(s) | Reference |
|---|---|
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| IGNITION All Models: Electrical Connections Secondary Ignition Wires Spark Plugs Fouled Ignition Switch TFI IV: Ignition Coil Ignition Module Rotor Alignment Distributor Cap, Adapter, Rotor and Stator DIS/EDIS: Single and Dual Hall Crank- shaft Sensors Hall Camshaft Sensor DIS/EDIS Ignition Module Coil Pack(s) | See IGNITION SYSTEMS in I - SYS/ COMP TESTS article. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Water/Dirt/Rust Contamina- tion in Fuel Fuel Lines Tank (Fuel Supply) Fuel Sender Filter Fuel Pressure Regulator Injectors Inertial Switch | Perform a visual inspection. See I - SYS/COMP TESTS article. |
| BASE ENGINE Compression Camshaft Timing. | Check engine mechanical condition. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| EXHAUST Component (Restricted) | Inspect exhaust system. |
| AIR INTAKE SYSTEM Air Tube | Check connections. |
DIAGNOSTIC CHART 4-CRANKS NORMALLY BUT WON'T START
CHART 5-SLOW RETURN TO IDLE
| System & Component(s) | Reference |
|---|---|
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Fuel Contamination Throttle Linkage | Perform a visual inspection. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| AIR INTAKE Air Leak | Perform a visual and audible inspection. |
DIAGNOSTIC CHART 5-SLOW RETURN TO IDLE
CHART 6-ROUGH IDLE
| System & Component(s) | Reference |
|---|---|
| IGNITION Scope Engine For: Spark Plug Coil, Secondary Ignition Wires, Distributor Cap, Adapter and Rotor, Ignition Timing | See BASIC TESTING article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Idle Airflow Electrical & Vacuum Com- ponents Fuel Pressure Regulator Injectors Fuel Rail Fuel Lines | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| COOLING Thermostatic Fan (Loose or Cracked) | Check Cooling System. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| BASE ENGINE Compression Valve Train Camshaft Intake Manifold Gaskets | Check Engine Mechanical Condition. |
| PCV Valve | See I - SYS/COMP TESTS article. |
| EVAP Components | See I - SYS/COMP TESTS article. |
| AIR INTAKE SYSTEM Air Tube Intercooler Tube (Thunderbird SC only) | Check connections. |
| CHARGING SYSTEM Components | Check charging system. |
| EXHAUST SYSTEM Components | Inspect exhaust system. |
| THERMACTOR Thermactor System Components | See I - SYS/COMP TESTS article. |
DIAGNOSTIC CHART 6-ROUGH IDLE
CHART 7-HIGH IDLE (ENGINE "DIESELS")
| System & Component(s) | Reference |
|---|---|
| FUEL/THROTTLE BODY Idle Airflow Throttle Plate & Linkage Speed Control Chain | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| AIR INTAKE SYSTEM Air Tube Intake Manifold Gasket | Perform a visual & audible inspection. |
| COOLING Overheating | Check cooling system. |
| AIR CONDITIONING A/C Clutch A/C Demand A/C Cyclic Pressure Switch A/C Refrigerant Charge | Check air conditioning system |
DIAGNOSTIC CHART 7-HIGH IDLE (ENGINE "DIESELS")
CHART 8-LOW IDLE (STALLS ON DECELERATION OR QUICK STOP)
| System & Component(s) | Reference |
|---|---|
| FUEL/THROTTLE BODY Idle Airflow Electrical & Vacuum Com- ponents | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| BASE TRANSMISSION (A/T WITH OVERDRIVE) Transmission Oil Level Converter Clutch Control Solenoid Modulated Converter Clutch Control Solenoid | See TESTS W/CODES article. |
DIAGNOSTIC CHART 8-LOW IDLE (STALLS ON DECELERATION OR QUICK STOP)
CHART 9-HESITATES OR STALLS
| System & Component(s) | Reference |
|---|---|
| IGNITION Scope Engine For: Spark Plug Coil, Secondary Ignition Wires, Distributor Cap and Rotor, Crossed Wires Ignition Timing | See BASIC TESTING article. |
| FUEL/THROTTLE BODY Idle Airflow Fuel Filter Fuel Pump Water/Dirt/Rust Contamina- tion in Fuel Fuel Lines Fuel Pressure Regulator Fuel Sender Filter Injectors | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| AIR INTAKE SYSTEM Air Tube Intercooler Tube (Thunderbird SC only) | Check connections. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| PCV Valve | See I - SYS/COMP TESTS article. |
| EXHAUST Restriction (W/Backpressure EGR system (PFE)) | See I - SYS/COMP TESTS article. |
| BASE TRANSMISSION (A/T WITH OVERDRIVE) Converter Clutch Control Solenoid Converter Clutch Override Converter Clutch Modulated Converter Clutch Control Solenoid | See I - SYS/COMP TESTS article. |
| BASE ENGINE Components | Check engine mechanical condition. |
DIAGNOSTIC CHART 9-HESITATES OR STALLS
CHART 10-MISSES UNDER LOAD
| System & Component(s) | Reference |
|---|---|
| IGNITION Scope Engine For: Spark Plug Coil, Secondary Ignition Wires, Distributor Cap, Adapter and Rotor Ignition Timing | See BASIC TESTING article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Fuel Lines Fuel Pressure Regulator Fuel Sender Filter Injectors | Perform a visual inspection. See I - SYS/COMP TESTS article. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| BASE ENGINE Components | Check engine mechanical condition. |
DIAGNOSTIC CHART 10-MISSES UNDER LOAD
CHART 11-SURGES AT STEADY SPEED
| System & Component(s) | Reference |
|---|---|
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Fuel Lines Fuel Pressure Regulator Fuel Sender Filter Octane Idle Airflow | Perform a visual inspection. See I - SYS/COMP TESTS article. |
| IGNITION Scope Engine For: Spark Plugs, Wires, Coil, etc. Secondary Ignition Wires Timing | See BASIC TESTING article. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| AIR INTAKE SYSTEM Air Intake Components | Perform a visual inspection. |
| EVAP Components | See I - SYS/COMP TESTS article. |
| BASE ENGINE Valve Train Camshaft Intake Manifold and Gaskets | Check Engine Mechanical Condition. |
| THERMACTOR Thermactor System Components | See I - SYS/COMP TESTS article. |
| SUPERCHARGER Assembly | See I - SYS/COMP TESTS article. |
| BASE TRANSMISSION (A/T WITH OVERDRIVE) Converter Clutch Control Components | See TESTS W/CODES article. |
DIAGNOSTIC CHART 11-SURGES AT STEADY SPEED
CHART 12-BACKFIRE (INTAKE OR EXHAUST)
| System & Component(s) | Reference |
|---|---|
| IGNITION Scope Engine For: Spark Plugs, Wires, Coil, etc. Crossed Wires, Ignition Timing | See BASIC TESTING article. |
| VACUUM DISTRIBUTION Vacuum Hoses, Connections | Perform a visual and audible inspection. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| THERMACTOR Thermactor System Components | See I - SYS/COMP TESTS article. |
| BASE ENGINE Intake Manifold and Gaskets Compression Checks Camshaft Valves | Check Engine Mechanical Condition. |
| EXHAUST Component (Restricted) | Inspect exhaust system. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Water/Dirt/Rust Contamina- tion in Fuel Fuel Lines Fuel Pressure Regulator Injectors Fuel Sender Filter Octane | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
DIAGNOSTIC CHART 12-BACKFIRE (INTAKE OR EXHAUST)
CHART 13-LACK OF POWER
| System & Component(s) | Reference |
|---|---|
| IGNITION Scope Engine For: Spark Plugs, Wires, Coil, etc. Crossed Wires, Ignition Timing | See BASIC TESTING article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Fuel Lines Fuel Pressure Regulator Fuel Sender Filter Injectors Idle Airflow | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| EXHAUST Component (Restricted) | Inspect exhaust system. |
| COOLING Thermostat | Check cooling system. |
| VACUUM DISTRIBUTION Vacuum Leaks | Perform a visual and audible inspection. |
| AIR INTAKE SYSTEM Air Cleaner Duct & Element | See I - SYS/COMP TESTS article. |
| EGR Valve | See I - SYS/COMP TESTS article. |
| BASE ENGINE Compression Check Camshaft Valves | Check Engine Mechanical Condition. |
| DRIVETRAIN Clutch, Automatic Trans. Brakes | Check transmission & drivetrain components. |
| SUPERCHARGER Assembly | See I - SYS/COMP TESTS article. |
DIAGNOSTIC CHART 13-LACK OF POWER
CHART 14-SPARK KNOCK (PINGS)
| System & Component(s) | Reference |
|---|---|
| IGNITION Timing | See ADJUSTMENTS article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| COOLING Overheating | Check cooling system. |
| BASE ENGINE Oil Level Compression Check Intake Manifold Gasket | Check Engine Mechanical Condition. |
| FUEL/THROTTLE BODY Fuel Filter Fuel Pump Fuel Lines Fuel Pressure Regulator Fuel Sender Filter Injectors | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| PCV Valve | See I - SYS/COMP TESTS article. |
| EGR Verify Correct Application, then Diagnose | See I - SYS/COMP TESTS article. |
| AIR INTAKE SYSTEM Air Cleaner Duct & Element | See I - SYS/COMP TESTS article. |
| THERMACTOR Thermactor System Components | See I - SYS/COMP TESTS article. |
| BASE TRANSMISSION (E4OD, AODE, AXOD-E) Transmission Controls | See TESTS W/CODES article. |
DIAGNOSTIC CHART 14-SPARK KNOCK (PINGS)
CHART 15-POOR FUEL ECONOMY
Note. Fuel consumption increases drastically in city driving, short-run operation, stop-and-go driving, trailer towing, extended winter warm-up periods, etc. Determine if these are factors are the cause of poor fuel mileage before proceeding with diagnostic procedure.
| System & Component(s) | Reference |
|---|---|
| FUEL/THROTTLE BODY Fuel Pressure Regulator Fuel Return Line Blocked | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article. |
| AIR INTAKE SYSTEM Air Cleaner Duct & Element | See I - SYS/COMP TESTS article. |
| IGNITION Scope Engine For: Spark Plugs, Wires, Coil, etc. Ignition Timing | See IGNITIONS SYSTEMS in I - SYS/ COMP TESTS article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| COOLING Thermostat | Check cooling system. |
| FACTORS EXTERNAL TO THE ENGINE Tire Pressure Clutch Operation Converter Clutch Override Automatic Transmission Shift Pattern and Fluid Level Brake Drag Exhaust System Speedometer/Odometer Gear Ratio Axle Ration Vehicle Load Road and Weather Conditions Aftermarket Add Ons | Perform a manual & visual inspection. |
| BASE TRANSMISSION (A/T WITH OVERDRIVE) Converter Clutch Control Components Modulated Converter Clutch Control Solenoid | See TESTS W/CODES article. |
| EGR Valve Operation | See I - SYS/COMP TESTS article. |
DIAGNOSTIC CHART 15-POOR FUEL ECONOMY
CHART 17-SHIFT INDICATOR LIGHT & AUDIBLE CHIMES ON
Note. Verify that the customer has read the Owner Guide on the Thunderbird SC overheat protection feature.
The Thunderbird SC is equipped with a Shift Indicator Light and Audible Chime that warns the customer when the engine oil or coolant overheats while the vehicle is operated at high speeds (above 100 MPH) for extended periods of time.
The Shift Indicator Light and Chime will also warn the customer when the engine has reached too high an RPM for that gear. The EEC-IV processor will reduce vehicle speed by limiting fuel to the engine when one of these overheat conditions has been reached. The customer may then notice a loss of power and/or a slight vibration. the Shift Indicator Light will "light" and the Audible Chime will produce a "steady tone" to alert the customer to upshift at the time.
Full power will be restored and the Shift Indicator Light and Chimes will turn off when the vehicle returns to normal operating temperatures.
| System & Component(s) | Reference |
|---|---|
| EEC EEC-IV Quick Test SIL Circuit Top Gear Switch | See TESTS W/CODES article. |
| THUNDERBIRD SC Audible Chime System | See CIRCUIT TEST KL in TESTS W/CODES article. |
DIAGNOSTIC CHART 17-SHIFT INDICATOR LIGHT & AUDIBLE CHIMES ON
CHART 18-IMPROPER SHIFT
| System & Component(s) | Reference |
|---|---|
| BASE TRANSMISSION (4EAT, A4LD, AOD-E, AXOD-E, E4OD) Converter Clutch Solenoid Converter Clutch Electronic Pressure Control Solenoid Shift Solenoids Modulated Converter Clutch Control Solenoid 4X4 Low Switch | See TESTS W/CODES article. |
| EEC CONTROLLED ELECTRONIC TRANSMISSION EEC-IV Quick Test | See TESTS W/CODES article. |
DIAGNOSTIC CHART 18-IMPROPER SHIFT
CHART 19-HIGH OIL CONSUMPTION
| System & Component(s) | Reference |
|---|---|
| EXTERNAL LEAKS Rocker Cover Gasket, Camshaft Seals, etc. | Perform a visual inspection. |
| PROPER DIPSTICK Over/Under Filling of Crank- case | Perform a visual inspection. |
| PCV Valve | Perform a visual inspection. |
| INTERNAL LEAKS (BLUE SMOKE FROM THE TAILPIPE) Valve Guides Valve Stem Seals Intake Manifold Gaskets Cylinder Head Drain Passages Piston Rings | Check engine mechanical condition. |
DIAGNOSTIC CHART 19-HIGH OIL CONSUMPTION
CHART 20-ENGINE RUNS HOT
| System & Component(s) | Reference |
|---|---|
| COOLING Thermostat Coolant Level Radiator or A/C Condenser Pressure Cap and/or Overflow System External Leaks Belts and Tension Fan and Fan Clutch Electric Fan (If Equipped) | Perform a visual inspection. Check cooling system. |
| GAUGES Sending Unit | See appropriate INSTRUMENT PANELS article in the ACCESSORIES/SAFTEY EQUIPMENT Section. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
| IGNITION Timing | See ADJUSTMENTS article. |
| BASE ENGINE Water Pump Core Sand in Block/Heads Internal Leaks | Check engine mechanical condition. |
| BRAKES Brakes Dragging | Check brake system. |
DIAGNOSTIC CHART 20-ENGINE RUNS HOT
CHART 21-ENGINE RUNS COLD
| System & Component(s) | Reference |
|---|---|
| GAUGE SYSTEM Gauge Sender | See appropriate INSTRUMENT PANELS article in the ACCESSORIES/SAFTEY EQUIPMENT Section. |
| COOLING Thermostat | Check cooling system. |
DIAGNOSTIC CHART 21-ENGINE RUNS COLD
CHART 22-EXHAUST SMOKE
| System & Component(s) | Reference |
|---|---|
| BLACK SMOKE (RICH MIXTURE) Air Cleaner Element Restricted Fuel Pressure Regulator Injectors Return Fuel Line Restricted EEC Components | Perform a visual inspection. See I - SYS/COMP TESTS article. See TESTS W/CODES article. |
| BLUE SMOKE (BURNING OIL) PCV Valve Guides/Stems/Seals Oil Drain Passages in Heads Piston Rings (not seated, seized, etc.) Cylinder Bores (scuffed) | Check engine mechanical condition. |
| WHITE SMOKE (COOLANT IN COMBUSTION) Intake Manifold Gasket Leaks, Cracked, Porous Cylinder Head Gasket Leaks, Cracked, Porous Engine Block Cracked, Porous | Perform a visual inspection. Checkcooling system. |
DIAGNOSTIC CHART 22-EXHAUST SMOKE
CHART 23-GAS SMELL
| System & Component(s) | Reference |
|---|---|
| FUEL/THROTTLE BODY Fuel Filter Leaks Injector Leaks Fuel Pump Leaks Fuel Lines Leaks Fuel Tank Leaks Fuel Tank Filler Neck Leaks Fuel Tank Sender Leaks Fuel Return Line Blocked Fuel Pressure Regulator Leaks | Perform a visual inspection. See FUEL SYSTEMS in I - SYS/COMP TESTS article |
| CANP Carbon Canister, Solenoid, Hoses Leak | See I - SYS/COMP TESTS article. |
| EEC EEC-IV Quick Test | See TESTS W/CODES article. |
DIAGNOSTIC CHART 23-GAS SMELL
CHART 25-ENGINE VIBRATES AT NORMAL SPEEDS
| System & Component(s) | Reference |
|---|---|
| ENGINE ACCESSORIES Fan Belt Drive Components Engine Mounts Engine Vibration Damper | Perform a manual and visual inspection. |
| NON-ENGINE Driveline Tires, Wheels Tire Balance | Perform a manual and visual inspection. |
| THUNDERBIRD 3.8L SC Shift Indicator Light and Audible Chime "ON" | See CHART 17 . |
DIAGNOSTIC CHART 25-ENGINE VIBRATES AT NORMAL SPEEDS