LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2003 >> Excursion 6.0 P, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 4 (Engine Controls - Trouble Shooting - No Codes - 7.3L Diesel) >> Symptoms >> Runs Rough, Misses, Bucks Or Jerks, Hesitation, Stumbles, Surges (On Acceleration Or Cruise), Lack Or Loss Of Power, Or Poor Fuel Economy

Runs Rough, Misses, Bucks Or Jerks, Hesitation, Stumbles, Surges (On Acceleration Or Cruise), Lack Or Loss Of Power, Or Poor Fuel Economy

WARNING: This page is about a different variant/trim than selected.
NOTE: The Powertrain Control Module (PCM) is equipped with an over RPM/speed limiting function that will shut off fuel delivery when predetermined engine speed is exceeded.

  1. Preliminary Checks

    Check brakes for dragging. Check transmission and axle fluid levels. Ensure transmission and axle bearings have not been overheated. Check for oil in coolant. Ensure engine oil level, viscosity and API rating meets specification. Ensure engine oil has been changed within last 5000 miles. Check air filter minder to see if filter needs to be replaced. Check Manifold Absolute Pressure (MAP) sensor hose for cracks, blockages or disconnection. Check intake manifold for leaks or restrictions. Check fuel quality. See TEST 2: SUFFICIENT CLEAN FUEL under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. Check vehicles laden weight with operator's expectations of vehicle performance. Check for engine overheating. Check wiring harness connectors for corroded, loose or damaged terminals. Repair any problems as necessary. If no problems are indicated, go to next step (Excursion and F250-F550) or go to step  3 (Econoline).

  2. Boost Pressure Test

    Perform BOOST PRESSURE TEST. Go to TEST KH: WASTEGATE CONTROL SOLENOID (EXCURSION & F250-F550) , step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Repair any problems as necessary. If no problems are indicated, go to next step.

  3. Perform KOEO On-Demand Self-Test

    Perform KOEO ON-DEMAND SELF-TEST under QUICK TEST in SELF-DIAGNOSTICS - 7.3L DIESEL article. If no DTCs are present, go to next step. If any DTCs are present, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 7.3L DIESEL article and perform appropriate SYSTEM TESTS.

  4. Perform KOEO Injector Electrical Self-Test

    Perform KOEO INJECTOR ELECTRICAL SELF-TEST under QUICK TEST in SELF-DIAGNOSTICS - 7.3L DIESEL article. If no DTCs are present, go to next step. If any DTCs are present, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 7.3L DIESEL article and perform appropriate SYSTEM TESTS.

  5. Retrieve/Clear Continuous DTCs

    Perform RETRIEVE/CLEAR CONTINUOUS MEMORY DTCS under QUICK TEST in SELF-DIAGNOSTICS - 7.3L DIESEL article. Record and clear any Continuous Memory DTCs retrieved. If Continuous Memory DTCs are present for Camshaft Position (CMP) sensor, go to next step. If no Continuous Memory DTCs are present for CMP sensor, go to step  8.

  6. Check Cold CMP Clearance (CMP DTC Present)

    Remove and inspect CMP sensor for contact with timing disk (visible scratches). CMP sensor is located right on front of engine, above crankshaft pulley. See Figure. If CMP sensor indicates signs of contact with timing disk, go to next step. If CMP sensor does not indicate any signs of contact with timing disk, replace CMP sensor.

  7. Check CMP Clearance To Timing Disk

    Replace CMP sensor and install a .010" (.254 mm) shim under CMP sensor. If symptom persists, increases shim thickness to .020" (.508 mm). Part No. (F7TZ-12J072-AA).

  8. Check Continuous Memory DTCs

    If any other Continuous Memory DTCs are present, perform appropriate system test under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. If no other Continuous Memory DTCs are present, go to next step.

  9. Check For Biased ICP Sensor

    Perform TEST DC: INJECTION CONTROL PRESSURE SENSOR , step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Repair any problems as necessary. If no problems are indicated, go to next step.

  10. Check Fuel Pump Pressure

    Perform TEST 8C: ELECTRIC FUEL PUMP PRESSURE TEST under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. Repair any problems as necessary. If fuel pump pressure is okay, go to next step.

  11. Check Fuel Regulator

    Check fuel regulator valve for sticking or contamination. Check fuel regulator "O" rings for damage. If fuel regulator valve or fuel regulator valve "O" rings require service, replace fuel regulator valve as a unit. If both fuel regulator valve and "O" rings are okay, go to next step.

  12. Check Pump Inlet Restriction

    Perform TEST 8D: ELECTRIC FUEL PUMP INLET RESTRICTION under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. Repair any problems as necessary. If no problems are indicated, go to next step.
    13. NOTE: Air may be present due to a recent repair on injection control pressure system. It may be necessary to drive vehicle aggressively for 15-20 miles to remove air from system. Engine must be at operating temperature prior to running aeration tests.

  13. Check For Aerated Engine Oil
    Perform TEST 10A: INJECTION CONTROL PRESSURE TEST (OIL AERATION/POOR IDLE) under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. If oil aeration problem is indicated, go to next step. If no problems are indicated, go to step  16.

  14. Check Source Of Aerated Engine Oil

    Overfill engine oil with 2 qts. (1.9L) of specified oil. Raise rear of vehicle and support 10" from ground. Using scan tool, access ICP PID from PID/DATA MONITOR & RECORD menu. Start engine and run at Wide Open Throttle (WOT) for 3 minutes. If ICP PID reading is more than 1.75 volts, or more than 1800 psi (12,411 kPa), oil is aerating due to lack of defoaming agents. Change engine oil to meet CG4/SH specifications, ensure engine oil level is correct and go to next step. If ICP PID reading is 1.75 volts or less, or 1800 psi (12,411 kPa) or less, aeration is caused by an injector "O" ring leak or a hole in oil pick-up tube. Repair as necessary.

  15. Injection Control Pressure Test

    Using scan tool, access ICP PID from PID/DATA MONITOR & RECORD menu. Start engine and run at WOT for 3 minutes. If ICP reading is more than 1.75 volt, or more than 1800 psi (12,411 kPa), go to next step. If ICP reading is 1.75 volt or less, or 1800 psi (12,411 kPa) or less, concern is no longer present.

  16. Check For Low IDM Power

    Go to TEST NA: INJECTOR DRIVE CIRCUIT OPERATION , step 29)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Repair any problems as necessary. If no problems are indicated, go to next step.

  17. Check Lubrication Pressure

    Check engine oil level in high pressure oil pump reservoir. Reservoir is located on top of engine, near generator. See Figure. Oil level should be within 1" (25.4 mm) of inspection plug. Connect a 100 psi (689.5 kPa) oil pressure gauge to high pressure oil pump reservoir. Ensure engine is at operating temperature. With engine idling at 650 RPM, engine oil pressure should be 12 psi (69 kPa) or more. Raise engine speed to 3300 RPM and check engine oil pressure. Engine oil pressure should be 40-70 psi (276-482 kPa). If engine oil pressure is as specified, go to next step. If engine oil pressure is not as specified, check for cause of low oil pressure and repair as necessary.

  18. KOER On-Demand Self-Test

    Ensure engine is at normal operating temperature. Clear DTCs. Perform KOER ON-DEMAND SELF-TEST under QUICK TEST in SELF-DIAGNOSTICS - 7.3L DIESEL article. If DTC P1211 is present, perform TEST 9C: MONITOR ICP PID WHILE CRANKING under HARD START/NO-START DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. If DTC P0476 is present, go to step  21. If no DTCs are present, perform TEST 11: CRANKCASE PRESSURE TEST under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. Repair any problems as necessary. If symptom persists, go to next step.

  19. Check Pressure Balance

    Remove high pressure hose from right cylinder head. See Figure. Using Fuel/Oil/Turbo Protector Cap Set (T94T-9395-AH), install appropriate cap on high pressure hose fitting on right cylinder head. Using plug from Oil High Pressure Leakage Test Adapter Set (303-S626), install plug into high pressure hose. Using scan tool, access and record Injection Pressure Regulator (IPR) PID duty cycle with engine running at 3000 RPM. Turn engine off. Remove cap and plug, and reinstall high pressure hose to right cylinder head. Remove high pressure hose from left cylinder head. See Figure. Using fuel/oil/turbo protector cap set, install appropriate cap on high pressure hose fitting on left cylinder head. Using plug from oil high pressure leakage test adapter set, install plug into high pressure hose. Using scan tool, check IPR PID duty cycle with engine running at 3000 RPM. If difference in IPR PID duty cycles between right and left bank is more than 2 percent, remove cap and plug, and reinstall high pressure hose to left cylinder head. Go to next step. If difference in IPR PID duty cycles between right and left bank is 2 percent or less, replace IPR. Remove cap and plug, and reinstall high pressure hose to left cylinder head.

  20. Check For Leak Source

    Remove valve cover from cylinder bank with higher IPR duty cycle. With engine idling, check for bubbling around injector bores or oil gallery drain plugs. Or with engine off, apply about 100 psi (689 kPa) of compressed air to high pressure oil gallery. Injector spill spouts may require removal for visibility. If air bubbles are noticeable or leaks are heard, replace "O" rings on injectors or reseal oil galleries as necessary. If no leaks are detected, perform KOER CYLINDER CONTRIBUTION SELF-TEST under QUICK TEST in SELF-DIAGNOSTICS - 7.3L DIESEL article. Repair as necessary.

  21. Check For Biased EBP Sensor

    Perform TEST DE: EXHAUST BACKPRESSURE SENSOR , step 21)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Repair circuits or replace EBP sensor as necessary. If EBP sensor is okay, go to next step.

  22. Check For Exhaust Restriction (KOER DTC P0476)

    Go to TEST KB: EXHAUST BACKPRESSURE REGULATOR , step 7)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Unplug EOT sensor to cause EBP valve to stay open. Using scan tool, access EBP PID from PID/DATA MONITOR & RECORD menu. Start engine and allow it to idle. Briefly accelerate engine speed to Wide Open Throttle (WOT) while monitoring EBP PID. If EBP PID is more than 25 psi (172 kPa), go to next step. If EBP PID reading is 25 psi (172 kPa) or less, go to step  24.

  23. Exhaust Backpressure Operation Test

    Inspect exhaust system for damage. Observe EBP valve operation while repeating KOER ON-DEMAND SELF-TEST. Go to TEST KB: EXHAUST BACKPRESSURE REGULATOR , step 8)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. If EBP valve cycles and then opens completely (tang against stop), check EBP adjustment. See Fig 1. If EBP valve does not cycle and then open completely, go to next step.
    Fig 1: Identifying Open Exhaust Backpressure Control Valve Position
    G95I35277Courtesy of FORD MOTOR CO.

  24. Check Electrical System

    Perform TEST KB: EXHAUST BACKPRESSURE REGULATOR under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article to ensure exhaust backpressure regulator and wiring are okay. Repair as necessary. If exhaust backpressure regulator and wiring are okay, go to next step.

  25. Check For Engine Wear

    Perform TEST 11: CRANKCASE PRESSURE TEST under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. If crankcase pressure reading is more than 3 in. H2O, go to next step to check engine mechanical condition. If crankcase pressure reading is 3 in. H2O or less, go to step  27.

  26. Check For Piston Or Valve Leaks

    Check engine compression. If compression reading is less than 350 psi (2413 kPa) and different from adjacent cylinders by 50 psi (345 kPa) or more, repair engine mechanical condition as necessary. See appropriate article in ENGINES. If compression reading is 350 psi (2413 kPa) or more and different from adjacent cylinders by less than 50 psi (345 kPa), replace affected injector.

  27. Check For Exhaust Restriction (No DTC)

    Perform TEST 13: EXHAUST RESTRICTION under ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article. If EBP PID value is more than 34 psi (234 kPa), or more than 2 volts, locate and repair restriction in exhaust system. If EBP PID value is 34 psi (234 kPa) or less, or 2 volts or less, go to next step.

  28. Check Fuel Injector Oil Discharge

    Remove valve covers. Monitor oil flow out of fuel injector spill spouts with engine at idle. If injector(s) have low oil flow from spill spouts, replace affected injector(s). If all injectors have good oil flow from injector oil spill spouts, turn ignition off and go to next step.

  29. Atmospheric Pressure Rationality Check

    Turn ignition on. Using scan tool, monitor EBP, MAP and BARO PIDs. PID values should not deviate from atmospheric pressure by more than 1.5 psi (10 kPa). If all PID values are within specification, go to next step. If any PID value is not within specification, perform appropriate system test for the sensor with the largest difference. If EBP PID value is not within specification, see TEST DE: EXHAUST BACKPRESSURE SENSOR under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. If MAP PID value is not within specification, see TEST DH: MANIFOLD ABSOLUTE PRESSURE SENSOR under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. If BARO PID value is not within specification, see TEST DG: BAROMETRIC PRESSURE SENSOR under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article.

  30. Check For Biased EOT Sensor

    Perform TEST DB: ENGINE OIL TEMPERATURE SENSOR , step 13)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. Allow vehicle to cool overnight. DO NOT start engine. Turn ignition on. Using scan tool, monitor EOT and IAT sensor PIDs. If EOT and IAT sensor values are within 11°F (6°C) of each other, go to next step. If EOT and IAT sensor values are not within 11°F (6°C) of each other, check EOT sensor wiring. See If EOT sensor wiring is okay, replace EOT sensor.

  31. Check EOT Sensor

    Start and warm up engine to 59-158°F (15-70°C). Remove fill plug from high pressure oil pump reservoir. Reservoir is located on top of engine, near generator. See Figure. Using an A/C thermometer, measure temperature of oil in high pressure oil pump reservoir. Using scan tool, monitor EOT sensor temperature reading. If readings between EOT sensor and A/C thermometer (oil temperature) are not within 5.4°F (3°C) of each other, check EOT sensor wiring. See TEST DB: ENGINE OIL TEMPERATURE SENSOR , step 14)  under SYSTEM TESTS in SELF-DIAGNOSTICS - 7.3L DIESEL article. If EOT sensor wiring is okay, replace EOT sensor. If readings between EOT sensor and A/C thermometer (oil temperature) are within 5.4°F (3°C) of each other, verify concern. See ENGINE PERFORMANCE DIAGNOSTIC PROCEDURES in SYSTEM & COMPONENT TESTING - 7.3L DIESEL article.
scientia non olet · About LEMON Manuals