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 the Powertrain On Board Diagnostic (OBD) System Check .

• | Refer to Intermittent Conditions before starting.

• | Search for bulletins.

Fuel System |

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

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

• | Inspect any items that can cause an engine to run lean (long term fuel trim significantly in the positive range). Refer to Diagnostic Aids for DTC P0171.

Ignition System | Test the spark plugs for proper heat range and reach.

• | 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 spark tester; 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 spark tester; 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
5000-8000ohms (5K-8Kohms)

- | 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
600ohms per foot (1 968ohms per meter).

| 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

Engine Cooling System | Inspect for obvious overheating problems:

• | Low engine coolant

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

• | Inoperative electric cooling fan circuits

• | Correct coolant solution should be a 50/50 mix--Refer to Coolant Description in Engine Cooling.

Engine Mechanical | Inspect for the following conditions:

• | Excessive oil in combustion chamber or leaking valve seals--Refer to Base Engine Misfire Diagnosis in Engine Mechanical.

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

• | Combustion chambers for excessive carbon buildup--Clean using top engine cleaner. Follow instructions on can.

• | Incorrect basic engine parts--Inspect the following components:

- | Camshaft

- | Cylinder heads

- | Pistons, etc.-- Refer to Base Engine Misfire Diagnosis in Engine Mechanical.

Additional |

• | Test for proper EGR system Operation. Refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient .

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

• | Test 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.