Knocking / Pinging

KNOCKING / PINGING DESCRIPTION

10	KNOCKING / PINGING
DESCRIPTION	Sound produced when air/fuel mixture is ignited by something other than spark plug

KNOCKING / PINGING INSPECTION/ACTION CHART

STEP	INSPECTION		ACTION
1	PRELIMINARY CHECKS Perform the following preliminary checks: Vacuum lines. Fuel (concerns such as fuel quality and proper grade). Engine overheating. Intake air system. Are all checks OK?	Yes	Go to next step.
1		No	Service as required. Verify symptom no longer exists.
2	CHECK IF ENGINE IS OVERHEATING NOTE: With the engine running and temperature stabilized, the ECT/CHT PID should be less than 112°C (234°F). Does the engine appear to be overheating?	Yes	Engine is overheating. See SYMPTOM TROUBLESHOOTING CHART - ENGINE COOLING SYSTEM .
2		No	Go to next step.
3	PERFORM PCM QUICK TEST See PCM QUICK TEST . Are any DTCs displayed during Continuous Memory Self-Tests, Key ON, Engine OFF (KOEO), Engine OFF (KOEO) or Key On, Engine Running (KOER)?	Yes	Check for cause. DIAGNOSTIC TROUBLE CODE NUMBERS .
3		No	Go to next step.
4	CHECK BASE ENGINE Check for base engine concerns (such as improper compression, worn camshaft/valve train, gasket leaks). Is a fault indicated?	Yes	Service as required.
4		No	Go to next step.
5	CHECK FUEL DELIVERY SYSTEM Perform fuel pressure inspection. TEST 9: FUEL LINE/FUEL PRESSURE HOLD INSPECTION . Fuel line pressure: 240-380 kPa (35-55 psi) Is fuel pressure correct?	Yes	Go to next step.
5		No	If pressure is greater than 380 kPa (55 psi): Replace fuel pump. See FUEL PUMP MODULE . If pressure is less than 240 kPa (35 psi): Check fuel supply line for restriction.
6	CHECK FUEL DELIVERY SYSTEM Check fuel pump fuel flow. TEST 4: FUEL DELIVERY SYSTEM . Did fuel system flow the required amount of fuel?	Yes	Check injector for leakage. See TEST 10: FUEL INJECTOR INSPECTION . If injector leaks, service as necessary. See FUEL INJECTORS . If injector OK, go to next step.
6		No	Check fuel supply line for restriction.
7	CHECK SECONDARY IGNITION SYSTEM Is strong blue spark visible at each disconnected high-tension lead while cranking engine?	Yes	Check spark plugs: If OK, Go to next step. If not OK, clean or replace spark plugs. See IGNITION COIL-ON-PLUG AND SPARK PLUG -- 2.3L , or IGNITION COIL-ON-PLUG AND SPARK PLUG -- 3.0L .
7		No	Check following: High-tension leads. CKP sensor. See CRANKSHAFT POSITION (CKP) SENSOR MALFUNCTION . CMP sensor. See CAMSHAFT POSITION SENSOR (CMP) MALFUNCTION .
8	CHECK PCV SYSTEM Remove PCV valve and shake it. Does PCV valve rattle?	Yes	Install PCV valve. Go to next step.
8		No	Replace PCV valve. See POSITIVE CRANKCASE VENTILATION (PCV) VALVE -- 2.3L .
9	CHECK PCV SYSTEM Start engine and bring to normal operating temperature. Disconnect crankcase ventilation hose from throttle body. Place a stiff piece of paper over the hose. Wait one minute. Does vacuum hold paper in place?	Yes	Go to next step.
9		No	Disconnect evaporative hose. Place a stiff piece of paper over the hose. Wait one minute. Does vacuum hold paper in place? If yes, see EVAPORATIVE EMISSION (EVAP) MONITOR AND SYSTEM MALFUNCTION . If no, check for vacuum leaks, obstructions in the PCV system, oil cap, PCV valve, rocker cover bolt torque/gasket leak. Service as required.
10	ADDITIONAL CHECKS Additional checks: Ignition base timing (if not previously checked). Intake air system. Engine oil quality. Are all checks OK?	Yes	Go to next step.
10		No	Service as required. Verify symptom no longer exists.
11	Verify test results. If OK, see DIAGNOSTIC INDEX to service any additional symptoms.