For 1990-2009 cars

Inspection/Test | Action
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DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.
Preliminary |

• | Refer to Diagnostic System Check - Engine Controls .

• | Refer to Intermittent Conditions before starting.

• | Search for bulletins.

Fuel System |

• | Test the fuel system circuits for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .

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

• | Test for faulty fuel injectors. Refer to Fuel Injector Balance Test with Special Tool , Fuel Injector Balance Test with Tech 2 , Fuel Injector Solenoid Coil Test test procedures.

• | Inspect for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

• | Inspect any items which may cause an engine to run rich, long term fuel trim is significantly in the negative range. Refer to Diagnostic Aids for DTC P0172 .

• | Inspect any items which may cause an engine to run lean, long term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Ignition System | Inspect the spark plugs for proper heat range and reach. Refer to Ignition System Specifications .

• | Inspect for proper ignition voltage output using the following steps:

1. | Attach the J 26792 Spark Tester to engine ground.

2. | Connect the spark plug end of the spark plug wire to the J 26792 . Leave the other end of the spark plug wire connected to the coil being tested.

3. | Connect the spark plug end of the companion spark plug wire to ground. The companion spark plug wire is the wire attached to the corresponding coil tower.

4. | Crank the engine while observing the J 26792 . A spark should be observed.

5. | Repeat the above steps for each coil.

• | If spark is not present at the coils, inspect for the following conditions:

- | Coils--Cracks, carbon tracking/arcing, or a resistance value outside the specified range

Coil Resistance
5000-8000 ohms (5K-8K ohms)

- | Spark plug wires--Signs of arcing, cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside the specified range

Spark Plug Wire Resistance
9 686 ohms per meter (3,000 ohms per foot)

| Important: : Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.

- | Defective ignition module

- | Ignition system wiring--Loose ignition module feed or ground connection, or damaged system wiring

• | Remove spark plugs and inspect for the following conditions:

- | Fouled plugs

- | Cracks

- | Wear

- | Improper gap

- | Burned or damaged electrodes

- | Improper heat range or reach

• | If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs. Refer to Spark Plug Inspection .

Engine Cooling System | Inspect for obvious overheating problems:

• | Low engine coolant

• | Restricted air flow to radiator, or restricted water flow through the radiator

• | Inoperative electric cooling fan circuits

• | Correct coolant solution should be a 50/50 mix. Refer to Cooling System Description and Operation in Engine Cooling.

Engine Mechanical |

• | Excessive oil in combustion chamber--Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical.

• | Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical.

• | For incorrect basic engine parts--Inspect the following conditions:

- | Cylinder heads

- | Camshaft and valve train components

- | Pistons, etc.

Additional |

• | Test for proper exhaust gas recirculation (EGR) system operation. Refer to DTC P0401 .

• | Inspect the Transaxle Range Switch input with the vehicle in drive and the gear selector in drive or overdrive.

• | Test the torque converter clutch (TCC) operation. TCC applying too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis in Automatic Transaxle.

• | If scan tool readings are normal and there are no engine mechanical faults, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87 and re-evaluate vehicle performance.