Engine knocking occurs repeatedly. Usually, it becomes particularly notable when accelerating. A sharp metallic sound is produced when the throttle opening angle is changed.
Perform the Diagnostic system check - engine controls.
Check if any problem exists in the vehicle.
Inspect whether smoke is present with combustion noise.
Inspect the fuel quality.
Verify the Injector ID Code of each cylinder.
Check the scan tool data list.
Check for related Service Bulletins.
Compare the Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), and Fuel Temperature parameters while the engine is cold. If the difference between the temperature values is 5°C {9°F} or more when the engine is cold, inspect for high resistance in each circuit and for a sensor malfunction.
{When the ignition switch is turned ON, the MAF sensor is heated, and as a result, the IAT shows a higher value than the normal intake air temperature.}
Observe the Fuel Rail Pressure (FRP) Sensor parameter on the scan tool. It is normal if the Fuel Rail Pressure (FRP) Sensor parameter shows approximately 20 MPa or more when the ignition switch is turned ON without starting the engine after the engine operation is stopped. If not, inspect for high resistance in each circuit and for a sensor malfunction.
Observe the Fuel Rail Pressure (FRP) parameter and Desired Fuel Rail Pressure (FRP) parameter while fully depressing the accelerator pedal from idling with the vehicle in neutral. The difference between the displays should always be within 5 MPa {725 psi}.
The CKP sensor is securely installed, and the sensor rotor is not damaged.
If there is excessive smoke, inspect the injector for being stuck open. Inspect the combustion chamber for fuel intrusion.
Remove the injector, and visually inspect.
Perform the Injector Cutoff with a scan tool.
Observe the Fuel Compensation parameter for each cylinder on the scan tool while idling.
Inspect the air cleaner, air intake duct, and intercooler for clogging, holes, or leakage.
Inspect the compression pressure of the engine.
Inspect the basic components of the engine including the camshaft, the cylinder head, and the pistons.
Inspect the combustion chamber for excessive oil intrusion.
Inspect the EGR bypass valve operation.
Inspect for any other cause that generates a similar sound, such as loose components, brackets, mounts, or a deteriorated clutch damper spring.