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Engine Controls - Tests W/o Codes - Eec-V (3.8L): Diagnosis Ford Mustang IV

Testing & Diagnostics ~2463 words

SYMPTOMS DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce diagnostic time, ensure steps in the BASIC TESTING - 3.8L and in the appropriate TESTS W/CODES - EEC-V (3.8L) articles 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. Fuel Pump Always On
  23. Gas Smell
  24. Sulfur Smell
  25. Engine Noise
  26. Vibration
  27. Climate Control (Lack Of Cooling)
  28. Climate Control (A/C Always On)
  29. A/C Does Not Go Off During WOT

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 the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If trouble code is present, perform appropriate CIRCUIT TEST.
  7. Check ignition switch.
  8. Check transmission linkage adjustment.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check cooling system for overheating (hard hot start only).
  5. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check Evaporative Emission (EVAP) system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check air intake system. See CIRCUIT TEST HU in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Check starting system.
  9. Check EGR system.
  10. Check for contaminated MAF sensor.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check for restricted air intake duct.
  3. Ensure Idle Air Control (IAC) solenoid controls idle speed. If IAC solenoid does not control idle speed, check IAC valve assembly. See CIRCUIT TEST KE in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check exhaust system for restriction. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. Go to CIRCUIT TEST TC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  9. Check engine compression. Check engine mechanical condition. Check camshaft and valvetrain components.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check for restricted air intake duct.
  3. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check engine compression. Check engine mechanical condition. Check intake manifold gasket and valve timing.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check for throttle body contamination. Check for carbon build-up around throttle plate.
  3. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check exhaust system for restriction. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check for restricted air intake duct.
  3. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check Idle Air Control (IAC). See step 2) of CIRCUIT TEST KE in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check exhaust system for restriction. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. Go to CIRCUIT TEST TC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  9. Check engine compression. Check engine mechanical condition. Check camshaft and valvetrain components.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check for restricted air intake duct.
  3. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check air intake system. See CIRCUIT TEST HU in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check idle speed. See IDLE SPEED in «ADJUSTMENTS - 3.8L»(ref-23150) article.
  3. Ensure Idle Air Control (IAC) solenoid controls idle speed. If IAC solenoid does not control idle speed, check IAC valve assembly. See CIRCUIT TEST KE in appropriate «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check air intake system. See CIRCUIT TEST HU in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check air intake system. Also, ensure throttle plate and linkages operate properly.
  3. Check EGR system. See the appropriate «SYSTEM/COMPONENT TESTING - EEC-V»(ref-22914) article.
  4. Ensure Idle Air Control (IAC) solenoid controls idle speed. If IAC solenoid does not control idle speed, check IAC valve assembly. See CIRCUIT TEST KE in the appropriate «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check EVAP system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  9. Check exhaust system for restriction. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  10. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. Go to CIRCUIT TEST TC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  11. Check engine compression. Check engine mechanical condition. Check valve timing.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check EGR system. See the appropriate «SYSTEM/COMPONENT TESTING - EEC-V»(ref-22914) article.
  3. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check EVAP system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check exhaust system. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check engine compression and valve timing. Check engine mechanical condition.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If fault codes are present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check exhaust system. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  6. Ensure transmission is functioning properly. If engine stalls during transmission engagement, check transmission solenoids. Go to CIRCUIT TEST TC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check for binding/dragging brakes.
  8. Ensure A/C turns off during Wide Open Throttle (WOT). If A/C does not turn off during WOT, go to step 130) of CIRCUIT TEST X in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check cooling system for overheating. If cooling system is overheating, go to ENGINE RUNS HOT symptom.
  3. Check ignition timing. See the «ADJUSTMENTS - 3.8L»(ref-23150) article.
  4. Check EGR system. See the appropriate «SYSTEM/COMPONENT TESTING - EEC-V»(ref-22914) article.
  5. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  6. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Check octane adjust system. See step 5) of CIRCUIT TEST FG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If available, check Technical Service Bulletins (TSBs) for OCT ADJ information.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check ignition system. See CIRCUIT TEST JB in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check exhaust system. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  7. Ensure engine operates at normal operating temperature.
  8. Ensure transmission operates properly.
  9. Check for dragging brakes.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check idle speed. See IDLE SPEED in «ADJUSTMENTS - 3.8L»(ref-23150) article.
  3. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  4. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  5. Check EVAP system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  6. Check air intake system. See CIRCUIT TEST HU in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  7. Check exhaust system. See CIRCUIT TEST HF in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  8. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.
  9. Ensure engine operates at normal operating temperature.
  10. Check EGR system. See the appropriate «SYSTEM/COMPONENT TESTING - EEC-V»(ref-22914) article.
  11. Ensure engine operates at normal operating temperature.
  12. Check engine compression. Check engine mechanical condition. Check intake manifold gasket, camshaft and valves.

Check the following items

  1. If Malfunction Indicator Light (MIL) does not come on, go to step 4) of CIRCUIT TEST NB in the appropriate «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If Transmission Control Indicator (TCIL) does not come on, go to step 6) of CIRCUIT TEST TB.
  2. If engine does not start, go to CIRCUIT TEST A in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  4. If Malfunction Indicator Light (MIL) is always on, go to step 1) of CIRCUIT TEST NB. If Transmission Control Indicator (TCIL) does not come on, go to step 8) of CIRCUIT TEST TB.

Perform QUICK TEST. See the TESTS W/CODES - EEC-V (3.8L) article. If code is present, perform appropriate CIRCUIT TEST. If code is not present, check transmission mechanical components.

Check the following items

  1. Check PCV system. See CIRCUIT TEST HG in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  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 the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check radiator cooling fan operation.
  3. Check base timing. See the «ADJUSTMENTS - 3.8L»(ref-23150) article.
  4. Check gauges/senders.
  5. Check for brake drag.
  6. Check transmission for overheating.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Check cooling system operation.
  3. Check temperature gauge and sender.

Perform QUICK TEST. See the TESTS W/CODES - EEC-V (3.8L) article. If code is present, perform appropriate CIRCUIT TEST. If code not present, go to step 175) of CIRCUIT TEST X.

Check the following items

  1. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  2. Check EVAP system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.

Check the following items

  1. Check fuel delivery system. See CIRCUIT TEST HC in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  2. Check EVAP system. See CIRCUIT TEST HV in the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article.
  3. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code is present, perform appropriate CIRCUIT TEST. If no codes present, go to step 110) of CIRCUIT TEST X.
  2. Check voltage at A/C clutch.
  3. Connect A/C manifold gauges, perform A/C system function test.

Check the following items

  1. Perform QUICK TEST. See the «TESTS W/CODES - EEC-V (3.8L)»(ref-23111) article. If code present, perform appropriate CIRCUIT TEST.
  2. Ensure that voltage at A/C clutch is less than 2 volts with A/C switch off. If voltage is 2 volts or more, go to step 1) of CIRCUIT TEST X.

Perform QUICK TEST. See the TESTS W/CODES - EEC-V (3.8L) article. If code is present, perform appropriate CIRCUIT TEST. If code not present, go to step 130) of CIRCUIT TEST X.

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, which may help in diagnosis. If code is not present, go to CIRCUIT TEST Z. See the appropriate TESTS W/CODES - EEC-V (3.8L) article.

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