Probable Causes
- Clogged air filter element.
- Obstructed air intake duct to turbo compressor.
- Obstructed air outlet duct from compressor to intake manifold.
- Obstructed intake manifold.
- Air leak in duct from air cleaner to compressor.
- Air leak in duct from compressor to intake manifold.
- Air leak at intake manifold-to-engine joint.
- Obstruction in exhaust manifold.
- Obstruction in exhaust system.
- Gas leak in exhaust manifold-to-engine joint.
- Gas leak in turbine inlet-to-exhaust manifold joint.
- Gas leak in ducts after turbine outlet.
- Obstructed turbocharger oil drain line.
- Obstructed engine crankcase ventilation.
- Turbocharger center housing sludged or coked.
- Engine camshaft timing incorrect.
- Worn engine piston rings or liners (blow-by).
- Internal engine problems (valves, pistons).
- Dirt caked on compressor wheel and/or diffuser vanes.
- Damaged turbocharger.
- Wastegate stuck open.