Engine Runs Rough; Engine Noises And Vibrations - Volvo 5.0OSiE-J Operator's Manual

Engine Runs Rough

If Fuel Injected, see EFI Di-
agnostic Manual
Engine Noises and
Vibrations
VPA 7748131 English 09-2007
If At Slow Speed - Check:
Idle speed and idle mixture.
Engine timing and spark plugs.
Fuel pump pressure.
Water or contaminants in fuel.
Manifold vacuum leak.
See Electrical/Ignition/Fuel Service Manual.
If At High Speed - Check:
Air leak on suction side of fuel system.
Too low octane fuel.
Ignition system secondary circuit.
Engine timing.
External fuel filters.
Fuel pump pressure.
Engine compression.
Water or contaminants in fuel, or water in cylinders.
See the Electrical/Ignition/Fuel System Service Manual.
Valves - Hydraulic Lifters
Rapping only when starting–oil too heavy for prevailing weather, var-
nish on lifter, oil needs to be changed.
Intermittent rapping–leakage at lifter check ball.
Idle noise–excessive leak down rate, faulty check ball seat.
Generally noisy–excessive oil in crankcase, stuck lifter plunger.
Loud noise at operating temperature–scored lifter plunger, fast leak
down rate, oil viscosity too light for prevailing weather or operating
temperatures.
See appropriate section in the applicable Engine Service Manual.
Ignition System (Ping or Knock)
Improper tuning.
Incorrect spark plug wire routing.
Use higher octane fuel.
See Electrical/Ignition/Fuel Service Manual.
Troubleshooting
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