Excessive Smoke. GMC Truck GMC Sierra Denali 2006

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2006 🢒 GMC Sierra Denali 🢒 Engine 🢒 Engine Controls - 6.6L 🢒 Excessive Smoke

Excessive Smoke Black

Inspection

Action

DEFINITION: Black smoke under load, idle or start up hot or cold.

Preliminary Inspection

•	Refer to Symptoms - Engine Controls .

•	Ensure the customer has an actual problem.

•	Normal Operation

-	During light to moderate acceleration there should be no black smoke.

-	During the 2-3 hard accelerations after normal light load driving there may be some black smoke momentarily but should not last for more than 5 seconds.

-	During hard acceleration there may always be a very faint puff of black smoke.

•	Abnormal Operation

-	Black smoke during light to moderate acceleration

-	Heavy black smoke during hard acceleration that lasts for more than 5 seconds

-	Heavy black smoke during every hard acceleration and/or during transmission shift transitions

•	Compare the scan tool data at idle with the scan tool data list. Refer to Scan Tool Data List .

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) 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 .

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.

Air Intake System Inspection

•	Inspect for an air leak in the charge air cooler or the air ducts between the turbocharger and the intake manifold. Refer to Charge Air Cooler Diagnosis .

•	Inspect for a restriction in the air cleaner or the air intake ducts.

•	Inspect for a restriction in the turbocharger charge air cooler.

•	Inspect for a restriction in the intake manifold.

•	Inspect that the EGR valve is fully closing. Remove the EGR valve and visually inspect that there is no light seen between the valves and the valve seats.

•	Ensure that the EGR valve does not bind when manually moving the valve.

Engine Mechanical Inspection

•	Inspect for incorrect basic engine parts such as the cam, the heads, the pistons, etc.

•	Inspect for excessive oil entering the combustion chamber. Refer to Oil Consumption Diagnosis .

Excessive Smoke Gray or Blue

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 .

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 .

Sensor Inspection

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.

Excessive Smoke White

Inspection

Action

DEFINITION: White smoke under load, idle or start up hot or cold.

Preliminary Inspection

•	Refer to Symptoms - Engine Controls .

•	Ensure the customer has an actual condition.

•	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 .

Fuel System Inspection

If excessive smoke is present, inspect for a stuck fuel injector. Refer to Fuel Injector Balance Test with Tech 2 .

Sensor Inspection

Air Intake System Inspection

•	Inspect the air cleaner and the air intake ducts for restriction.

•	Inspect for a restriction in the turbocharger charge air cooler.

•	Inspect for a restriction in the intake manifold. Refer to Intake Manifold Cleaning and Inspection .

Engine Mechanical Inspection

•	Inspect for incorrect basic engine parts such as the cam, the heads, the pistons, etc.

•	Inspect for coolant entering the combustion chamber.