Checks
| Action
|
Definition:
A mild to severe ping, usually worse under acceleration. The engine makes
sharp metallic knocks that change with throttle opening.
|
Preliminary Checks
|
| • | Refer to Important Preliminary Checks. |
| • | Make sure the customer has an actual problem. |
| • | Check the fuel quality. Refer to Specific Gravity Check in Fuel
Systems. |
|
Cooling
System Checks
|
| • | Check for obvious overheating problems. Refer to the appropriate
service manual. |
| • | Check for a low engine coolant level. |
| • | Check for a loose water pump belt. |
| • | Check for restricted air flow through the radiator, or restricted
coolant flow. |
| • | Check for a faulty or incorrect thermostat. |
| • | Check for a correct coolant solution. The solution should be a
50/50 mix of anti-freeze and water. |
|
Sensor Check
|
| • | Check the Engine Coolant Temperature (ECT) sensor using the scan
tool to compare the engine coolant temperature with the ambient air temperature
on a cold engine. If the coolant temperature reading is more than 5° greater
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. |
|
Fuel System
Checks
|
| • | Check for air leaks in fuel supply to injection pump. Refer to
Fuel System Diagnosis in Fuel Systems. |
| • | Check the injection pump static timing. Refer to Fuel Systems. |
| • | Check the injection nozzles. Refer to Fuel Systems. |
|
Engine Mechanical
Checks
|
| • | Check for incorrect basic engine parts such as cam, heads, pistons,
etc. |
| • | Check for excessive oil entering combustion chamber. |
|
Additional
Checks
| Check the Service
Bulletins for control module software updates.
|
