Excessive Smoke (Gray or Blue)

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

Inspection	Action
DEFINITION: Gray or blue smoke under load, idle or start up hot or cold.
Preliminary Inspections	Refer to Symptoms - Engine Controls . Ensure the customer has an actual problem. Check the coolant level in the reservoir. White coolant smoke may be mistaken for blue/gray smoke. If the coolant level is low refer to Loss of Coolant . Compare the scan tool data at idle with the scan tool data list. Refer to Scan Tool Data List (Engine Control Module) or Scan Tool Data List (Glow Plug Control Module) .
Fuel System Inspection	Observe the actual vs. desired fuel rail pressure with a scan tool, with the engine running. If the engine control module (ECM) glow plug control module (GPCM) or a fuel injector has recently been replaced, it may be necessary to confirm the fuel injector flow rate values. Refer to Fuel Injector Flow Rate Programming . Inspect the fuel injectors. Refer to Fuel Injector Balance Test with Tech 2 (Manual Transmission) or Fuel Injector Balance Test with Tech 2 (Automatic Transmission) .
Sensor Inspection	Inspect the engine coolant temperature (ECT) sensor. Use the scan tool in order to compare the ECT with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5 degrees more or less than the ambient air temperature on a cold engine, inspect for a high resistance in the coolant sensor circuit or the sensor itself. Turn ON the ignition with the engine OFF. Observe the actual fuel rail pressure (FRP) with a scan tool. The actual FRP should be between 1.1-1.8 MPa. If it is not, inspect for high resistance in the FRP sensor circuits or the FRP sensor. Refer to Circuit Testing and Wiring Repairs .
Air Intake System Inspection	Inspect the air cleaner and the air intake ducts for restriction. Inspect for contamination of the mass air flow (MAF) sensor. Inspect for a restriction in the turbocharger charged air cooler. Inspect for a restriction in the intake manifold.
Engine Mechanical Inspection	Perform a cylinder leakage test. Perform the engine compression test. Refer to Engine Compression Test . Inspect for incorrect basic engine parts such as the cam, the heads, the pistons, piston rings, and valves. Inspect for excessive oil entering the combustion chamber. Refer to Oil Consumption Diagnosis .
Turbocharger Inspection	Inspect for leaking seals in the turbocharger. A slight film on the intake side is normal.