NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [WITHOUT WU-TWC]


13	KNOCKING/PINGING - ACCELERATION/CRUISE
DESCRIPTION	Sound is produced when air/fuel mixture is ignited by something other than the spark plug (e.g., hot spot in combustion chamber).
POSSIBLE CAUSE	• Engine overheating due to cooling system malfunction • ECT sensor malfunction • IAT sensor malfunction • MAF sensor malfunction • Knock sensor 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 performing the fuel system services: • 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 the "BEFORE REPAIR PROCEDURE" and "AFTER REPAIR PROCEDURE" described in this manual. (See BEFORE REPAIR PROCEDURE.) (See AFTER REPAIR PROCEDURE.) Caution • If there is foreign material on the connecting area of the quick release connector, it might damage the connector or fuel pipe. To prevent this, disconnect the connector and clean the connecting area before connecting.


STEP	INSPECTION	RESULTS	ACTION
1	Connect the WDS or equivalent to the DLC-2. Access the ECT PID. Verify that the ECT PID is less than 116°C {241°F} while driving. Is the ECT PID less than the specification?	Yes	Go to the next step.
1		No	Inspect the cooling system for the cause of overheating.
2	Connect the WDS or equivalent to the DLC-2. Access the IAT, MAF and SPARKADV PIDs. Monitor each PID. (See PCM INSPECTION [WITHOUT WU-TWC].) Are the PIDs normal?	Yes	Go to the next step.
2		No	IAT PID: Inspect the IAT sensor MAF PID: Inspect the MAF sensor SPARKADV PID: Inspect the CMP sensor and knock sensor.
3	Connect the WDS or equivalent to the DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. (See KOEO/KOER SELF-TEST.) Are any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test.
3		No	No DTC is displayed: Go to the next step.
4	Is the engine compression correct? (See COMPRESSION INSPECTION [ZJ, ZY].)	Yes	Go to the next step.
4		No	Inspect for cause.
5	Install a fuel pressure gauge between fuel pipe and the fuel distributor. Start the engine and idle it. Measure the fuel line pressure at idle. Is the fuel line pressure correct at idle? (See FUEL LINE PRESSURE INSPECTION.)	Yes	Inspect the ignition timing.
5		No	Zero or low: Inspect the fuel pump relay and fuel pump related circuits. Inspect for fuel leakage inside the pressure regulator. Inspect for a clogged main fuel line. High: Inspect the pressure regulator for cause of the high pressure. Inspect for a clogged fuel return line. Inspect the vacuum hose to the pressure regulator.
6	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, replace or reprogram the PCM.