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Engine Controls - Tests W/o Codes - Eec-Iv Mercury Sable II

Testing & Diagnostics ~4989 words

INTRODUCTION

Before diagnosing symptoms or intermittent faults, perform steps in BASIC TESTING and G - EEC-IV TESTS W/CODES articles in the ENGINE PERFORMANCE Section. Use this article to diagnose driveability problems existing when a hard fault code is not present or vehicle is not equipped with a self-diagnostic system.

Note. Some driveability problems may have been corrected by manufacturer with a revised Powertrain Control Module (PCM). Check with manufacturer for latest PCM application.

Symptom checks can direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component or system test and/or adjustment.

Use intermittent test procedures to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present, but no problem was found during self-diagnostic testing.

Note. For specific testing procedures, see I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. For specifications, see ADJUSTMENTS or SPECIFICATIONS articles in the ENGINE PERFORMANCE Section.

SYMPTOMS DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING and G - EEC-IV TESTS W/CODES articles in the ENGINE PERFORMANCE Section were performed before diagnosing a symptom. Symptom checks are listed in order of probability, ease of accomplishment, and accessibility. Symptoms available for diagnosis are as follows.

  1. No Crank
  2. Hard Start/Long Crank
  3. Stalls After Start
  4. No Start/Normal Crank
  5. Slow Return To Idle
  6. Rough Idle
  7. High Idle (Diesels/Runs On)
  8. Low Idle (Stalls On Deceleration)
  9. Hesitates Or Stalls
  10. Surge (On Acceleration Or Cruise)
  11. Backfires
  12. Loss Of Power
  13. Spark Knock
  14. Poor Fuel Economy
  15. Emissions Compliance
  16. Warning Indicator Lights
  17. Improper Transmission Shift
  18. High Oil Consumption
  19. Engine Runs Hot
  20. Engine Runs Cold
  21. Exhaust Smoke
  22. Gas Smell
  23. Engine Noise
  24. Vibration
  25. Climate Control (Lack Of Cooling)
  26. Climate Control (A/C Always On)

Preliminary Checks

Check battery connections. Check starter relay connections. Check alarm/anti-theft devices. Check all fuse links. On A/T models, ensure gearshift is in Park. On M/T models, ensure clutch is fully depressed.

Symptom Checks

Check the following items

  1. Check starter relay.
  2. Check starter circuit.
  3. Check charging circuit.
  4. Check for seized/hydro-locked engine (leaking injectors).
  5. Check for defective flywheel.
  6. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  7. Check ignition switch.
  8. Check transmission linkage adjustment.
  9. On models with distributor ignition, check for short to ground in starter wire.

Check for vacuum leaks. Check fuel quality. Check air cleaner/air intake duct.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  3. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check cooling system for overheating (hard hot start only).
  5. Check PCV system.
  6. Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  7. On 2.3L Mustang, check for spark. See step 25) of CIRCUIT TEST NB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  8. Check starting system.
  9. On Mark VIII, check high speed fuel pump operation. See indicated step 15 of CIRCUIT TEST XB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  10. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  11. Check for contaminated MAF sensor.

Check for vacuum leaks. Check fuel quality. Check for restricted air filter/air intake duct. Check wiring harness connectors.

Check the following items

  1. Perform QUICK TEST and check for codes. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  3. Check Idle Air Control (IAC). See step 1) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  4. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  5. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  6. If engine stalls during parking maneuvers, check Power Steering Pressure (PSP) switch operation. See step 3) of CIRCUIT TEST FF in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  7. If engine stalls during transmission engagement, check transmission solenoids. Go to CIRCUIT TEST TC in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  8. On Probe 2.0L M/T, if engine stalls because of low fast idle (cold engine), go to step 25) of CIRCUIT TEST KE in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If engine has low idle or stalls with blower motor on, go to step 10) of CIRCUIT TEST FE. If engine has low idle or stalls with daytime running lights on, go to step 20) of CIRCUIT TEST FE. If engine has low idle or stalls with headlights on, go to step 30) of CIRCUIT TEST FE. If engine has low idle or stalls with rear window defroster on, go to step 40) of CIRCUIT TEST FE.
  9. Check for restricted exhaust system.
  10. Check for restricted air intake duct.
  11. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  12. Check engine compression. Check engine mechanical condition. Check camshaft and valve train components.
  13. Ensure transmission is functioning properly.

NO START/NORMAL CRANK

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 secondary air supply, operate engine until surplus fuel is used up, and then reconnect secondary air supply.

Check fuel quality. Check Inertia Fuel Shutoff (IFS) switch. Check alarm/anti-theft devices. Check wiring harness connectors. Check for disconnected or restricted air intake duct. Check fuses and relays.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. On models with Distributor Ignition (DI), perform CIRCUIT TEST AA. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. On 3.8L SC, 3.0L SHO, 3.2L SHO, and 2.3L OHC, perform CIRCUIT TEST AB. On all other models, perform CIRCUIT TEST AC.
  3. Check for restricted exhaust system.
  4. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.

Check for vacuum leaks. Check throttle linkage operation. Check air intake system. Check throttle body.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check for throttle body contamination. Check for carbon build-up around throttle plate.

Check ignition wiring harness connectors. Check air intake duct. Check for vacuum leaks. Check for cracked or missing cooling fan blades. Check for broken motor mounts. Check air filter.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  3. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  4. Check fuel pump. See FUEL SYSTEM in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  5. Check PCV system.
  6. Ensure engine operates at normal operating temperature.
  7. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  8. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  9. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  10. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  11. Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  12. Check charging system.
  13. Check exhaust system.
  14. On 3.0L SHO and 3.2L SHO, check Intake Manifold Runner Control (IMRC). See step 6) in CIRCUIT TEST KT under G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

HIGH IDLE (DIESELS/RUNS ON)

Note. If engine runs on (diesels) after ignition is turned off, check for faulty ignition switch or short to power in IGN RUN circuit. If engine is overheating, go to ENGINE RUNS HOT symptom. If engine runs cold, go to ENGINE RUNS COLD symptom.

Check for vacuum leaks. Check for carbon build-up on throttle plate. Check throttle linkage operation. Check for binding/sticking cruise control chain. Check air intake duct. Check for leaking intake manifold gasket.

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  3. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  4. On 3.8L SC, if high idle exists with transmission in Drive, go to step 12) of CIRCUIT TEST TA in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  5. Check A/C system operation.
  6. Ensure engine operates at normal operating temperature.

Check for vacuum leaks. Check Idle Air Control (IAC) solenoid connections.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  3. On A/T models with overdrive, check transmission solenoids. See CIRCUIT TEST TC in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  4. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  5. Low idle exists with A/C on, go to step 30) of CIRCUIT TEST KM in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  6. On Probe 2.0L M/T, if engine has low idle or stalls when engine is cold (no fast idle), go to step 25) of CIRCUIT TEST KE in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If engine has low idle or stalls with daytime running lights on, go to step 20) of CIRCUIT TEST FE. If engine has low idle or stalls with blower motor on, go to step 10) of CIRCUIT TEST FE. If engine has low idle or stalls with headlights on, go to step 30) of CIRCUIT TEST FE. If engine has low idle or stalls with rear window defroster on, go to step 40) of CIRCUIT TEST FE.

HESITATES OR STALLS

Note. The PCM is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined speed is exceeded.

Check vacuum hose routing. Check for restricted air filter/air intake duct. Check fuel quality. Check wiring harness connectors. Check ignition wiring.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  3. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  5. Check PCV system.
  6. Ensure driveline and transmission are functioning properly.
  7. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  8. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  9. Check for restricted exhaust system.
  10. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  11. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  12. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.

Check vacuum hose routing. Check for restricted air filter/air intake duct. Check fuel quality. Check wiring harness connectors.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  3. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  5. Check PCV system.
  6. If surge occurs with A/C on, check A/C clutch operation.
  7. Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  8. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  9. Ensure engine operates at normal operating temperature.
  10. Ensure transmission operates properly.
  11. Check for restricted exhaust system.
  12. On 3.8L SC, ensure supercharger is functioning properly. See AIR INDUCTION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  13. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  14. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  15. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  16. Check Heated Oxygen Sensor (HO2S) heater. On all except Taurus Flex Fuel models, go to step 21) of CIRCUIT TEST H in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. On Taurus Flex Fuel models, go to step 15) of CIRCUIT TEST HB.
  17. Ensure cruise control system is functioning properly.

Check vacuum hose routing. Check spark plug wiring for incorrect firing order.

Check the following items

  1. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  2. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  3. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  5. Check for restricted exhaust system.
  6. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

LOSS OF POWER

Note. The PCM is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined speed is exceeded.

Verify symptom is reported under normal driving conditions without engine under excessive load conditions. Check vacuum hose routing. Check for restricted air filter. Check wiring harness connectors. Check for obstructed radiator. Check transmission fluid.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  3. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  5. Check for restricted exhaust system.
  6. Ensure engine operates at normal operating temperature.
  7. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  8. On 3.0L SHO and 3.2L SHO, check Intake Manifold Runner Control (IMRC). See step 6) of CIRCUIT TEST KT in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  9. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  10. Ensure transmission is functioning properly.
  11. On 3.8L SC, ensure supercharger operates properly. See AIR INDUCTION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  12. Check for binding/dragging brakes.
  13. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  14. Ensure A/C turns off during Wide Open Throttle (WOT). On all models except Mark VIII, if A/C does not turn off during WOT, go to CLIMATE CONTROL (LACK OF COOLING) symptom.
  15. On Mark VIII, check high speed fuel pump operation. See step of CIRCUIT TEST XB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Check vacuum hose routing. Check for restricted air filter. Check fuel quality.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check cooling system for overheating. If cooling system is overheating, go to ENGINE RUNS HOT symptom.
  3. Check base timing. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  4. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  5. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  6. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  7. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  8. Check PCV system.
  9. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  10. Ensure transmission is functioning properly.
  11. Check oil quality.

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 factors are the cause of poor fuel mileage before proceeding with diagnostic procedure.

Check for restricted air filter/air intake duct. Check transmission fluid level. Check fuel quality.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  3. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  4. Check for restricted exhaust system.
  5. Ensure engine operates at normal operating temperature.
  6. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  7. Ensure transmission operates properly.
  8. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  9. Check PCV system.
  10. Check for dragging brakes.
  11. Check for contaminated Mass Airflow (MAF) sensor.

EMISSIONS COMPLIANCE

Canada and some states or metropolitan areas in the United States require periodic idle emission tests. All Ford products have been designed to pass these tests. If a Ford product fails an idle Emission test, it is probable that the engine temperature was not warm and stabilized prior to the test or the vehicle had idled excessively long prior to the test. Before starting any services, verify complaints of idle emission test failure by using test procedure of area that failed vehicle.

The following encompasses most of the emissions measurement modes of current state idle test procedures

  1. Ensure engine is at normal operating temperature and all accessories are turned off.
  2. Check emissions at idle.
  3. Operate engine at 2200-2800 RPM.
  4. Check emissions within 30 seconds.
  5. Return engine speed to idle.
  6. Check emissions within 30 seconds.

If any emission component is changed, Keep-Alive Memory (KAM) should be cleared before repeating state emission test procedure. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Check for vacuum leaks/blockage. Check wiring harness connectors. Ensure vehicle scheduled maintenance is current.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  3. Check power to MAP/BARO sensor. See step 3) of CIRCUIT TEST S in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  4. Check idle speed. See IDLE SPEED in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  5. Check PCV system.
  6. Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  7. Check secondary air injection. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  8. Check for restricted exhaust system.
  9. Check EGR system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  10. On Mark VIII, check Intake Manifold Runner Control (IMRC). See step 6) of CIRCUIT TEST KT in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  11. Ensure engine operates at normal operating temperature.
  12. Check engine compression. Check engine mechanical condition. Check intake manifold, manifold gasket, camshaft and valves.
  13. Check PCV system.

WARNING INDICATOR LIGHTS

Thunderbird SC is equipped with a shift indicator light and audible chime, warning driver of engine oil or coolant overheat while vehicle is operated at high speeds (above 100 MPH) for extended periods of time. The shift indicator light and chime will also warn driver when the engine has reached too high an RPM for that gear. The Powertrain Control Module (PCM) will reduce vehicle speed by limiting fuel to the engine when one of these overheat conditions has been reached. The driver may then notice a loss of power and/or a slight vibration. The shift indicator light will turn on and the audible chime will produce a steady tone to alert driver to upshift at this time. Full power will be restored and the shift indicator light and chimes will turn off when the vehicle returns to normal operating temperatures.

Check the following items

  1. On all models check if Malfunction Indicator Light (MIL) or shift indicator light is on, perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. If MIL never comes on, go to step 4) of CIRCUIT TEST ML in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  3. On Continental, if Data Communications Link (DLC) light is on, go to step 25) of CIRCUIT TEST ML in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Check transmission fluid level and condition. Check for transmission leaks. Check wiring harness connectors. Check for vehicle modifications. Check for electronic add-on items. Check for misadjusted shift linkage.

Note. The following symptom checks are for A4LD, AXODE, AODE, E4OD and 4EAT transmissions only.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. On Escort and Tracer, if transmission stays in 3rd gear with shift selector in "D" or OD, go to step 9) of CIRCUIT TEST TD in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Check for external engine oil leaks. Check for proper oil dipstick. Check for proper oil viscosity.

Check the following items

  1. Check PCV system.
  2. Check engine mechanical condition. Check valves, valve guides, valve stem oil seals, intake manifold gaskets, cylinder head oil drain passages and piston rings.

Check coolant level. Check for coolant leaks. Check fan belt. Check radiator fan connectors. Check water/anti-freeze mixture. Check radiator condition. Check for collapsed/restricted radiator hose. Check radiator cap. Check overflow system.

Check the following items

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check radiator cooling fan operation (if equipped). Start engine. Turn A/C on. Cooling fan should be on.
  3. Check base timing. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
  4. Check gauges/senders.
  5. Check for brake drag.
  6. Check transmission for overheating.
  7. Check for core sand in engine block.
  8. Check for internal cylinder block and cylinder head leaks.

Check radiator cooling fan wiring harness.

Check the following items

  1. Check if radiator cooling fan runs continuously.
  2. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  3. Check cooling system operation.
  4. Check temperature gauge and sender.

Black Smoke (Rich Mixture)

  1. Check for restricted air cleaner/air intake duct.
  2. Check for restricted fuel return hoses.
  3. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  4. Check fuel pressure. On all models except Taurus Flexible Fuel (FF), go to step 2) of CIRCUIT TEST H in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. On Taurus FF, go to step 2) of CIRCUIT TEST HB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
  5. Check ignition system. See IGNITION SYSTEMS in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  6. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

Blue Smoke (Burning Oil)

  1. Check PCV system.
  2. Check engine mechanical condition. Check valve guides, valve stems, valve seals, oil drain passages in cylinder heads (Blue smoke on start-up), piston rings and cylinder bores.

White Smoke (Water In Combustion)

  1. On Probe 2.0L M/T, visually check for coolant leak in by-pass air valve.
  2. Check for cylinder head gasket leaks, intake manifold gasket leaks and cracked engine block.

Check fuel system for leaks.

Check the following items

  1. Check fuel delivery system. See FUEL SYSTEM in I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  2. Check Evaporative Emission (EVAP) system. See I - EEC-IV SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.
  3. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.

Squeal, Click Or Chirp

  1. Check for low oil level.
  2. Check valve train components.
  3. Check drive belts.
  4. Check EEC-IV solenoids.

Rattle

  1. Check for loose components.

Hiss

  1. Check for cooling system leaks.
  2. Check for vacuum leaks.
  3. Check for loose spark plugs.
  4. Check for air intake leaks.
  5. Check for secondary air injection leaks.
  6. Check for Evaporative Emission (EVAP) system leaks.

Snap

  1. Perform a visual/audible check of secondary ignition system.

Rap Or Roar

  1. Check for exhaust leak.
  2. Check for secondary air injection leaks.

Knock

  1. Check for worn rod/main bearings.
  2. Check for loose piston pins.
  3. Check piston to cylinder bore clearance.
  4. Knock (Detonation) - See SPARK KNOCK under SYMPTOMS.

VIBRATION

  1. Check radiator cooling fan.
  2. Check drive belt.
  3. Check engine mounts.
  4. Check crankshaft vibration damper.
  5. Check transmission.
  6. Check tires and wheels.
  7. Check driveline components.

Perform a visual inspection of A/C system. Check A/C switches. Check fuses.

  1. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.
  2. Check voltage at A/C clutch.
  3. Connect A/C manifold gauges and perform A/C system function test.

Check for shorted A/C wiring. Check A/C heater control. Check A/C compressor.

Check the following items

  1. Ensure voltage does not exist at A/C clutch with A/C switch off.
  2. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code is present, perform appropriate CIRCUIT TEST.

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code (on some systems), which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.

Intermittent Simulation

To reproduce the conditions creating an intermittent fault, use the following methods

  1. Lightly vibrate component.
  2. Heat component.
  3. Wiggle or bend wiring harness.
  4. Spray component with water.
  5. Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for self-diagnostic codes. See G - EEC-IV 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 G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Continuous Monitor Mode (Wiggle Test)

In this mode, the technician can attempt to re-create an intermittent fault while monitoring the system. This mode, also called the wiggle test, may be used in Key On Engine Off (KOEO) and Key On Engine Running (KOER) self-test modes. See CIRCUIT TESTS in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for instructions on the use of this procedure to identify intermittent faults in specific circuits or components.

KOEO Wiggle Test

Connect test equipment. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. Turn ignition on. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test to enter wiggle test. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a code may be stored in memory and indicated at the diagnostic tester or scan tool. Record or retrieve code, and perform CIRCUIT TEST indicated in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

KOER Wiggle Test

Connect test equipment. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. Turn ignition off, and wait 10 seconds. Start engine. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test to enter wiggle test. DO NOT turn engine off. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a code may be stored in memory and indicated at the diagnostic tester or scan tool. Record or retrieve code, and perform CIRCUIT TEST indicated in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

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