Checks
| Action
|
Definition: White,
black, gray or blue smoke under load, idle or start up hot or cold.
|
Preliminary Check
|
| • | Make sure the vehicle has an actual problem. |
| • | 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 Injection Timing Adjustment
. |
| • | 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. |
|
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 Compression Test
in Engine Mechanical. |
| • | Check for a "step" or sheared camshaft drive key. |
| • | 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 the battery and the grounds. Refer to
Battery Check
in Engine Electrical. |
|
