For 1990-2009 cars

Inspection | Action
--- | ---
DEFINITION: A mild to severe ping which usually occurs worse while under acceleration. The engine makes sharp metallic knocks that change with throttle opening.
Preliminary |

• | Refer to Important Preliminary Inspections before starting in Symptoms - Engine Controls .

• | Inspect the engine control system grounds for being clean, tight, and in the correct locations. Refer to Engine Controls Schematics . Ensure the resistance between the engine control module (ECM) housing and the battery negative cable is less than 0.5 ohms.

• | Verify that the ECM and ECM bracket fasteners are at the correct torque.

• | If the scan tool readings are normal and there are not any engine mechanical faults, fill the fuel tank with a known high quality fuel that meets the vehicle's minimum octane requirements. Road test the vehicle and re-evaluate the vehicle's performance.

Fuel System |

• | Test for incorrect fuel pressure. Refer to Fuel System Diagnosis .

• | Test for a restricted fuel filter. Refer to Fuel System Diagnosis .

• | Test for a contaminated fuel condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Test the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .

• | Test the items that can cause an engine to run lean. For a lean condition, refer to DTC P2177 or P2179 and DTC P2187 or P2189 .

Sensor/System | Use a scan tool to monitor the knock sensor (KS) system. Refer to Knock Sensor (KS) System Description .
Ignition System | Ensure that the spark plugs are the correct heat range. Refer to Ignition System Specifications .
Engine Cooling System | Test for obvious overheating conditions. Test or inspect for the following conditions:

• | Low engine coolant level

• | Incorrect engine coolant

• | Restricted air flow to the radiator or restricted coolant flow through the radiator

• | Engine coolant leaks

| Refer to the following procedures in Engine Cooling:

- | Cooling System Draining and Filling

- | Engine Overheating

Engine Mechanical |

• | Inspect for the following engine mechanical conditions:

- | Excessive oil in combustion chambers and for leaking valve seals

- | High cylinder compression

- | Incorrect camshaft timing

- | Excessive carbon buildup in the combustion chambers--Clean the chambers using top engine cleaner. Follow the instructions on the can.

- | For more information, refer to the following procedures:

• | Oil Consumption Diagnosis

• | Engine Compression Test

• | Camshaft Timing Drive Chain Alignment Diagram

• | Setting Camshaft Timing

• | Symptoms - Engine Mechanical

• | Inspect the following components for incorrect basic engine parts:

- | Camshafts

- | Cylinder heads

- | Pistons, connecting rods, or bearings

- | Refer to the following procedures:

• | Camshaft Timing Drive Components Cleaning and Inspection

• | Camshaft Cleaning and Inspection

• | Cylinder Head Cleaning and Inspection

• | Piston, Connecting Rod, and Bearing Cleaning and Inspection

Additional | Test the transmission torque converter clutch (TCC) for the correct operation. Applying the TCC too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis .