Smoke Diagnosis Charts

WARNING: This page is about a different variant/trim than selected.

The following charts include possible causes and corrections for excess or abnormal exhaust smoke. Small amounts of exhaust smoke (at certain times) are to be considered normal for a diesel powered engine.

EXCESSIVE BLACK SMOKE
POSSIBLE CAUSE	CORRECTION
Air filter dirty or plugged.	Check and replace the filter if necessary.
Air intake system restricted.	Check the entire air intake system including all hoses and tubes for restrictions, collapsed parts or damage. Repair/replace as necessary.
Air Leak in Intake System.	Check the entire air intake system including all hoses and tubes for collapse, cracks, loose clamps, or holes in rubber ducts. Also check the intake manifold for loose mounting hardware.
Diagnostic Trouble Codes (DTCs) active or multiple, intermittent DTCs.	Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Powertrain Control Module (PCM) has incorrect calibration.	Refer to PCM PROGRAMMING .
Exhaust system restriction is above specifications.	Check the exhaust pipes for damage/restrictions. Repair as necessary.
Fuel grade is not correct or fuel quality is poor.	Temporarily change fuel brands and note condition. Change brand if necessary.
Fuel injection pump malfunctioning.	A DTC may have been set. If so. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Fuel injector malfunctioning.	A DTC may have been set. Perform "Injector Classification Programming" using scan tool. Also and, Return Fuel Quantity Test. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Fuel injector lower washer doubled or missing.	Remove and inspect the fuel injector washer.
Fuel return system restricted.	Check the fuel return lines for restriction.
Intake manifold restricted.	Remove the restriction.
Manifold Air Pressure (Boost) Sensor or sensor circuit malfunctioning.	A DTC should have been set. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Turbocharger air intake restriction.	Remove the restriction.
Turbocharger damaged.	Replace the turbocharger.
Turbocharger has excess build up on compressor wheel or diffuser vanes.	Clean the turbocharger with a suitable cleaner.
Turbocharger wheel clearance out of specification.	Replace the turbocharger.

EXCESSIVE WHITE SMOKE
POSSIBLE CAUSE	CORRECTION
Air in the fuel supply: Possible leak in fuel supply side.	Inspect the fuel system.
Coolant leaking into the combustion chamber.	Perform the cooling system pressure test.
Diagnostic Trouble Codes (DTCs) active or multiple, intermittent DTCs.	Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
In very cold ambient temperatures, engine block heater is malfunctioning (if equipped).	Refer to ENGINE COOLING, DIAGNOSIS AND TESTING .
Powertrain Control Module (PCM) has incorrect calibration.	A DTC should have been set. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Fuel filter plugged.	Refer to CHECKING THE FUEL DELIVERY SYSTEM .
Fuel grade not correct or fuel quality is poor.	Temporarily change fuel brands and note condition. Change brand if necessary.
Fuel injector malfunctioning.	A DTC should have been set. Perform "Injector Identification Programming" or "Cylinder Cutout Test" using scan tool to isolate individual cylinders. Also. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Fuel injector hold-down(s) loose.	Replace the copper washer(s) (shim) and tighten to specifications.
Fuel injector protrusion not correct.	Check washer (shim) at bottom of fuel injector for correct thickness.
Fuel injection pump malfunctioning.	A DTC should have been set. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Fuel supply side restriction.	Refer to CHECKING THE FUEL DELIVERY SYSTEM for fuel system testing.
Intake manifold air temperature sensor malfunctioning.	A DTC should have been set. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Intake manifold heater circuit not functioning correctly in cold weather.	A DTC should have been set. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) . Also check the heater elements for correct operation.
Intake manifold heater elements not functioning correctly in cold weather.	A DTC should have been set if heater elements are malfunctioning. Refer to DTC INDEX (1 OF 2) and/or DTC INDEX (2 OF 2) .
Internal engine damage (scuffed cylinder).	Analyze engine oil and inspect oil filter to locate area of probable damage.
Restriction in fuel supply side of fuel system.	Refer to CHECKING THE FUEL DELIVERY SYSTEM for fuel system testing.

EXCESSIVE BLUE SMOKE
POSSIBLE CAUSE	CORRECTION
Dirty air cleaner or restricted turbocharger intake duct.	Check the air cleaner housing for debris and replace filter as necessary.
Air leak in boost system between turbocharger compressor outlet and intake manifold.	Service the charge air system.
Obstruction in exhaust manifold.	Remove the exhaust manifold and inspect for blockage.
Restricted turbocharger drain tube.	Remove the turbocharger drain tube and remove obstruction.
Crankcase ventilation system plugged.	Inspect the oil separator system for function and clear drain back hole in cylinder head cover/intake manifold.
Valve seals are worn, brittle, or improperly installed.	Replace the valve stem oil seals.
Valve stems or guides are worn.	Remove the valves and inspect valves and guides.
Broken or Improperly installed piston rings.	Tear down the engine and inspect piston rings.
Excessive piston ring end gap.	Remove the pistons and measure piston ring end gap.
Excessive cylinder liner wear and taper.	Remove the pistons and measure cylinder liner wear and taper.
Cylinder damage.	Remove the pistons and inspect cylinder liner for cracks or porosity. Repair with new cylinder liner if necessary.
Piston damage.	Remove the pistons and inspect for cracks, holes. Measure piston for out-of-round and taper.
Turbocharger failure.	Replace the turbocharger.