Engine Troubleshooting

  1. ENGINE WILL NOT CRANK
    1. Perform Electrical Troubleshooting
    2. Remove serpentine belt
    3. Remove all glow plugs. Using socket and breaker bar at crankshaft pulley, rotate engine clockwise and check for mechanical or hydraulic seizure.
      1. If crankshaft will not turn, check for bearing failure.
      2. If crankshaft turns and liquid is discharged, determine if liquid is coolant or fuel.
      3. If coolant is discharged, remove cylinder heads\ and check for cracked cylinder heads or leaking head gaskets.
      4. If fuel is discharged, remove and test fuel injection nozzles for breaks or leakage.
    4. Remove converter housing cover and check for damaged flywheel. Replace flywheel if damaged.
    5. Check starting system; refer to Electrical Troubleshooting
  2. ENGINE CRANKS BUT WILL NOT START
    1. Using tachometer, check engine cranking speed. Ensure speed is 180 rpm minimum.
      1. If cranking speed is too low, proceed to step b.
      2. If cranking speed is OK, proceed to step c.
    2. Ensure battery is fully charged and starting circuit connections are connected. Refer to Electrical Troubleshooting. NOTE: Bubbles in fuel stream, and white exhaust smoke seen during cranking may indicate the presence of air in the fuel system.
    3. Drain fuel filter a maximum of 30 seconds while cranking engine.
      1. If water and/or contamination are present, wait two minutes and repeat test twice more.
      2. If water and/or contamination are still present, drain and clean fuel tank and refuel vehicle.
    4. Check pressure at fuel pump outlet. If pressure is not at least 4 psi (28 kPa), replace fuel pump.
    5. Check fuel supply pressure at fuel lift pump outlet using pressure gauge. Pressure should be 4 psi (28 kPa) minimum.
      1. If pressure is not at least 4 psi (28 kPa), clean or replace fuel filter and repeat test.
      2. If pressure is still not at least 4 psi (28 kPa), check fuel supply lines and hoses for restrictions and obvious damage. Replace any damaged lines or hoses.
    6. Check electrical connections on injection pump. Ensure lead is connected to fuel solenoid terminal (front terminal) and cold-advance solenoid terminal (right rear terminal).
    7. Check for voltage at fuel solenoid; perform Electrical Troubleshooting
    8. Check operation of fuel solenoid. Disconnect lead from terminal on top of injection pump. Turn ignition switch to ACC. Touch lead to fuel solenoid terminal and remove; audible clicking sound should be heard
      from within pump. If no sound is heard, repair or replace as required.
    9. Check operation of glow plug system; refer to Electrical Troubleshooting
    10. Loosen fuel injection lines at nozzles, and crank engine. If no fuel leaks from fuel injection lines while cranking engine, replace fuel injection pump.
    11. Remove and test fuel injection nozzles for correct operating pressure. Opening pressure of nozzle must be between 2,030 psi (13,997 kPa) and 2,204 psi (15,197 kPa). If operating pressure is below 2,030 psi
      (13,997 kPa), replace fuel injection nozzles
    12. Using compression tester, check compression of each cylinder following steps 1 through 7: NOTE: Compression reading may exceed 450 psi (3,102 kPa).
      1. Remove all glow plugs.
      2. Remove air cleaner element
      3. Disconnect fuel solenoid lead from fuel injection pump. CAUTION: Do not add oil to any cylinder when checking compression or damage to engine may result.
      4. Install compression gauge adapter in glow plug hole of cylinder being tested and connect compression gauge.
      5. Crank engine, allow engine to crank long enough to accumulate six compression pulses, and record highest reading.
      6. Repeat steps (4) and (5) for remaining cylinders. NOTE: If any cylinder measures below the 80% variable, the following components may be at fault: damaged valves, warped or cracked cylinder heads, or worn or damaged pistons or piston rings.
      7. All cylinders should build up quickly and evenly to a minimum of 300 psi (2,068 kPa), and lowest reading should not be less than 80% of highest reading cylinder.
  3. ENGINE STOPS DURING NORMAL OPERATION
    1. Check for restrictions in air intake system. Check air cleaner-to-air horn elbow and air horn for damage that would restrict air flow. Replace damaged parts.
    2. Check for restrictions in exhaust system. Inspect for any damage that would restrict exhaust flow. Replace damaged parts.
    3. Perform steps 2C through 2J.
  4. ENGINE KNOCKS (MECHANICAL)
    1. Remove converter housing cover, and torque capscrews securing torque converter to 35 lb-ft (48 N•m).
    2. Remove fuel injection nozzles and test for chatter. Injectors will chatter when working properly.
    3. Check for worn or damaged connecting rod bearings and main bearings. Replace worn or damaged connecting rod and main bearings.
    4. Check for worn or damaged crankshaft. Replace worn or damaged crankshaft.
    5. Check for worn or damaged pistons and connecting rods. Replace worn or damaged pistons and connecting rods.
  5. ENGINE SMOKES DURING NORMAL OPERATION
    1. Perform steps 3A through 3C.
  6. EXCESSIVE OIL LOSS OR CONSUMPTION - NOTE: Blue smoke coming from exhaust, in conjunction with excessive oil consumption, may indicate the engine is burning oil.
    1. Check for oil leaks at pan, drain plug, valve covers, timing gear cover seal, oil filter and adapter, oil dipstick tube, oil cooler, and oil cooler lines and fittings. Tighten any loose connections, or replace any damaged parts.
    2. Check for defective valve seals. Replace defective valve seals.
    3. Check for worn valve guides. Repair worn valve guides.
    4. Check for worn or damaged piston rings. Replace worn or damaged piston rings.
  7. LOW OIL PRESSURE (ACCORDING TO GAUGE)
    1. Check for oil leaks at pan, drain plug, valve covers, timing gear cover seal, oil filter and adapter, oil dipstick tube, and oil cooler lines and fittings. Tighten any loose connections, or replace any damaged parts.
    2. Check operation of oil pressure gauge; refer to Electrical Troubleshooting
    3. Check for defective oil pump. Replace defective oil pump.
    4. Check for worn or damaged main bearings and rod bearings. Replace worn or damaged main bearings and rod bearings.
    5. Check for worn or damaged crankshaft. Replace worn or damaged crankshaft.
  8. EXCESSIVE ENGINE VIBRATION
    1. Check engine mounts and insulators for looseness or damage. Tighten any loose fasteners, and replace damaged parts.
    2. Check for air in fuel lines. Bleed air from fuel lines and check for air source.
    3. Remove and test fuel injection nozzles for chatter. Injectors will chatter when working properly.
    4. Remove converter housing cover, and torque capscrews securing torque converter to 35 lb-ft (48 N•m).
    5. Check for damaged flywheel or missing counterweight on flywheel. Replace flywheel if damaged or if counterweight is missing.
    6. Check for loose or damaged torsion damper. Replace torsion damper if damaged.
  9. EXCESSIVE EXHAUST SMOKE
    1. Black Smoke
      1. Check for restricted exhaust pipe, intake manifold or dirty air filter. Replace exhaust pipes or intake manifold if restricted. Clean or replace dirty filter.
      2. Remove and perform pressure check and leak check on fuel injection nozzles.
      3. Check fuel injection pump timing.
      4. Check for defective fuel injection pump. Replace defective fuel injection pump.
    2. White Smoke (Hot)
      1. Check for leaking or defective water pump.
        1. If water pump checks OK, go to step 2.
        2. If water pump is leaking or defective, replace.
      2. Remove surge tank cap, and with engine running, check for excessive bubbles in surge tank. If bubbles are present, remove cylinder heads and check for defective head gaskets, cracked cylinder heads, or cracked block.
      3. Remove and test fuel injection nozzles.
      4. Check for defective fuel injection pump. Replace defective fuel injection pump.
    3. Blue Smoke
      1. Perform Electrical Troubleshooting.
      2. Check for defective valve seals. Replace defective valve seals.
      3. Check for worn valve guides. Repair worn valve guides.
      4. Check for worn or damaged pistons, piston rings, and cylinder block. Repair or replace as necessary.
  10. ACCELERATOR PEDAL STICKS OR FULL THROTTLE CANNOT BE OBTAINED
    1. Inspect accelerator pedal bushing for binding or damage that would limit pedal travel. Replace bushing if damaged.
    2. Inspect accelerator cable for kinks, corrosion, or damage which would restrict cable movement. Replace accelerator cable if damaged.
    3. Inspect throttle bracket return spring on left side of injection pump for damage which would restrict accelerator cable movement. Replace spring if damaged.
    4. Disconnect accelerator cable from fuel injection pump. Move throttle lever on injection pump to wide open throttle. If throttle lever does not move freely, replace injection pump.
  11. ENGINE DOES NOT DEVELOP FULL POWER
    1. Check vehicle electrical system for battery voltage throughout the starting and charging systems; refer to Electrical Troubleshooting.
    2. Check fuel filter for obstructions. Replace fuel filter if clogged or dirty.
    3. Check lift pump operation. Replace if damaged.
    4. Check for air in injection lines. Bleed air from injection lines if present.
    5. Check fuel injection pump timing. Adjust as necessary.
    6. Remove and test fuel injection nozzles for correct spray pattern and nozzle opening pressure. Opening pressure must be between 2,030 psi (13,997 kPa) and 2,204 psi (15,197 kPa).
    7. Check for defective fuel injection pump. Inspect drive gear for broken or missing teeth. Check injector pump housing for cracks or damage. Replace injector pump if damaged.
    8. Perform cylinder compression test; refer to step 2K.
    9. Check for burned or cracked valves. Replace burned or cracked valves.
    10. Check for worn or damaged pistons and piston rings. Replace worn or damaged pistons or piston rings.
    11. Check for damaged camshaft or lifters. Ensure lifters are not collapsed. With a dial indicator, measure camshaft lobes for wear. Intake and exhaust lift will measure 0.280 ± 0.002 in. (7.112 ± 0.05 mm). Replace
      camshaft if any lobe is worn or damaged.
  12. LUBRICATING OIL DILUTED
    1. Remove and test for leaking fuel injection nozzles.
    2. Perform cylinder compression test; refer to step 2K.
    3. Check for broken piston rings. Leaking injector nozzles may allow fuel to run down into cylinder. Replace broken piston rings.
  13. AUXILIARY DRIVE SYSTEM NOISE
    1. Check drivebelt for frays, cracks, or fluid contamination. Replace damaged or contaminated belt.
    2. Check drivebelt tension.
    3. Check grooves in drive pulleys for scoring or damage. Check pulleys for looseness. Tighten loose pulleys or replace damaged pulleys.
    4. Check for defective water pump, power steering pump, air conditioning compressor (if so equipped), and alternator.

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