Checks
| Action
|
DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with the throttle opening.
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Preliminary Checks
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| • | Ensure the vehicle has an actual problem. |
| • | Inspect for smoke associated with the combustion noise. Refer to Fuel System Checks below. |
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Cooling System Checks
|
| • | Inspect for a low engine coolant level. |
| • | Inspect for any restricted air flow through the radiator. Refer to
Radiator Cleaning
. |
| • | Inspect for a malfunctioning or incorrect thermostat. |
| • | Inspect for a correct coolant solution. The solution should be a 50/50 mix of anti-freeze and water. |
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Sensor Inspection
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| • | Inspect the engine coolant temperature (ECT) sensor by using the scan tool in order to compare the ECT with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5 degrees more or less than the ambient air
temperature on a cold engine, check for a high resistance in the coolant sensor circuit or the sensor itself. |
| • | Inspect the CKP sensor reluctor wheel. Remove the CKP sensor and attempt to move the reluctor wheel front to back or side to side with a probe. If there is any movement the reluctor wheel retaining bolts are loose. |
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Fuel System Checks
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Important: Fuel additives are not recommended.
Inspect for the following:
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Engine Mechanical Checks
|
| • | Inspect for incorrect basic engine parts such as cam, heads, pistons, etc. |
| • | If the engine control module (ECM) glow plug control module (GPCM) or a fuel injector has recently been replaced, it may be necessary to confirm the fuel injector flow rate values. Refer to
Fuel Injector Flow Rate Programming
. |
| • | Inspect for any excessive oil entering combustion chamber. |
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Additional Checks
| Compare the scan tool data at idle with the scan tool data list. Refer to
Scan Tool Data List
.
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