Detonation/Spark Knock/Pings

DESCRIPTION
A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening. Sounds like popcorn popping.

INSPECTION
To help determine if the conditions is caused by a rich or lean system, the car should be driven at the speed of the complaint. Monitoring block learn, at the complaint speed, will help identify the cause of the problem. If the system is running lean (block learn greater than 150), refer to diagnostic aids for Diagnostic Trouble Code 44. DTC 44
If the system is running rich (block learn less than 110), refer to Diagnostic Trouble Code 45. DTC 45

^ Check for obvious overheating problems: Low coolant, Loose belt, Restricted air flow to radiator, or restricted water flow through radiator, Inoperative electric cooling fan circuit. Refer to C-charts Component Testing / Chart C-12A. Chart C-12A Coolant Fan Control Circuit

^ Exhaust Gas Recirculation (EGR) system for not opening or plugged EGR passages. Refer to C-charts Component Testing / Chart C-7. Chart C-7 Exhaust Gas Recirculation (EGR) Check

^ Electronic Spark Control (ESC) system for no retard. Refer to C-charts Component Testing / Chart C-5. Chart C-5 Electronic Spark Control (ESC) Check

^ Park/Neutral switch. Be sure "Scan" indicates drive with gear selector in drive or overdrive. Refer to C-charts Component Testing / Chart C-1A. Chart C-1A Park/Neutral Switch Diagnosis

^ [1][2]Torque Converter Clutch (TCC) operation, TCC applying too soon. Refer to C-charts Component Testing / Chart C-8A (3T40). Chart C-8A Torque Converter Clutch (TCC) Electrical Diagnosis

^ Fuel system pressure. Refer to C-charts Component Testing / Chart C-7. Chart C-7 Exhaust Gas Recirculation (EGR) Check

^ Engine for excessive carbon build-up. Remove carbon with top engine cleaner. Follow instructions on can.

^ Mem-Cal for correct part. (See Technical Service Bulletins)

^ Combustion chamber for excessive oil.

^ Engine for incorrect basic parts such as cam, heads, pistons, etc..

^ Fuel for poor quality, proper octane rating.