No. 13 Knocking/Pinging-Acceleration/Cruise

13	KNOCKING/PINGING - ACCELERATION/CRUISE
DESCRIPTION	Sound is produced when the air/fuel mixture is ignited by something other than the spark plug (such as hot spot in combustion chamber).
POSSIBLE CAUSE	Engine overheating due to cooling system malfunction ECT sensor malfunction IAT sensor malfunction MAF sensor malfunction KS malfunction Erratic signal from CMP sensor Inadequate engine compression Inadequate fuel pressure WARNING: The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before servicing the fuel system: Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel. Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete "BEFORE SERVICE PRECAUTION " and "AFTER SERVICE PRECAUTION ". CAUTION: Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.

DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	Access the ECT PID. Verify the ECT PID is less than 116°C {241°F} during driving. Is the ECT PID less than the specification?	Yes	Go to the next step.
1		No	Inspect the cooling system for cause of overheating.
2	Access the IAT and MAF PIDs. Monitor the each PID. Are the PIDs normal? (See PCM INSPECTION ).	Yes	Go to the next step.
2		No	IAT PID is not normal: Inspect the IAT sensor. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION ). MAF PID is not normal: Inspect the MAF sensor. (See MASS AIR FLOW (MAF) SENSOR INSPECTION ).
3	Turn the ignition switch to the ON position (engine off). Are there any DTCs displayed?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE ).
3		No	Go to the next step.
4	Is the engine compression correct? (See COMPRESSION INSPECTION ).	Yes	Go to the next step.
4		No	Inspect for cause.
5	Install the fuel pressure gauge between fuel pipe and fuel distributor. Start the engine and idle it. Measure the fuel line pressure during idle. Is the fuel line pressure correct during idle? (See FUEL LINE PRESSURE INSPECTION ).	Yes	Inspect the ignition timing.
5		No	Low: Inspect the fuel pump relay and fuel pump circuit. Inspect the fuel line for clogging. If there is no malfunction, replace the fuel pump unit. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ). High: Replace the fuel pump unit (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
6	Inspect the KS. (See KNOCK SENSOR (KS) INSPECTION ). Is the KS normal?	Yes	Inspect the valve timing. (See VARIABLE VALVE TIMING ACTUATOR INSPECTION
6		No	Replace the KS. (See KNOCK SENSOR (KS) REMOVAL/INSTALLATION ).
7	Verify test results. If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX ). If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If vehicle is repaired, troubleshooting completed. If vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION ).