GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Chevy P32 RV/Van Chassis 🢒 Engine 🢒 Engine Controls - 6.5L (L65) 🢒 Excessive Smoke

Checks

Action

Definition: White, black, gray or blue smoke under load, idle or start up hot or cold.

Preliminary Check
    • Refer to Symptoms .
    • Make sure the vehicle has an actual problem.
    • Check the PCM grounds for being clean, tight and in their proper locations. Refer to Engine Controls Components .
    • Check the fuel quality. Refer to Fuel Quality Diagnosis .

Fuel System Checks
    • Check for a restriction in the fuel return system. Refer to Fuel Return System Diagnosis .
    • Check the injection pump timing. Refer to Fuel Injection Pump Timing Adjustment .
    • Check for insufficient fuel. Refer to Fuel Supply System Check .
    • Check the injection nozzles. Refer to Injection Nozzle(s) Diagnosis .
    • Check for possible internal damage to the injection pump caused by debris.

Sensor Check
    • Check the Engine Coolant Temperature (ECT) sensor by using the Scan Tool in order to compare the engine coolant temperature with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5° greater or less than the ambient air temperature on a cold engine, check for a high resistance in the coolant sensor circuit or the sensor itself.
    • Check the glow plug system operation. Refer to Glow Plug System Check .

Air Intake System Check
    • Black smoke indicates a possible restriction in the air cleaner or the air intake ducts.
    • Check for a restriction in the turbo charger inlet duct.
    • Check for a restriction in the intake manifold.

Engine Mechanical Check
    • If there is white or light blue smoke coming out of the exhaust, this is fuel vapor that did not ignite (this condition is caused by insufficient heat in the cylinder). Check for low cylinder compression. Refer to Engine Mechanical.
    • Check for a "step" or sheared camshaft drive key. Refer to Engine Mechanical
    • Check for incorrect basic engine parts such as the cam, the heads, the pistons, etc.
    • Large amounts of black smoke, check for any excessive oil entering the combustion chamber.

Starting and Charging System Check
    • If the engine cranks to slowly, high injection pressures will not be reached (approximately 100 RPM (cold) and 180 RPM (hot).
    • Check starter for proper operation. Refer to Starting and Charging System.
    • Check the battery and the grounds. Refer to Starting and Charging System.