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Detonation / Spark Knock
DETONATION / SPARK KNOCK - DIAGNOSIS PROCEDURE
| Step |
Action |
Value(s) |
Yes |
No |
| 1 |
Were the Important Preliminary Checks performed? |
- |
Go to Step 2. |
Go to Symptom Diagnosis . |
| 2 |
- Fill the fuel tank with a known good grade of gasoline that has the octane rating of the value specified.
- Reevaluate the vehicle's performance.
Does the detonation problem still exist? |
87 - 89 octane |
Go to Step 3. |
System OK |
| 3 |
- Inspect for low engine coolant level.
- Check for restricted airflow to the radiator or restricted coolant flow.
- Check for a faulty thermostat.
- Check for an incorrect coolant solution.
Is the problem found? |
- |
Go to Step 4. |
Go to Step 5. |
| 4 |
Repair or replace any cooling system components as needed.
Is the repair complete? |
- |
System OK |
- |
| 5 |
- Check the engine coolant temperature using the scan tool.
- Replace the Engine Coolant Temperature (ECT) sensor if the resistance is not within specifications as listed in the Diagnostic Aids for diagnostic trouble code P0118.
Is the problem found? |
- |
Go to Step 6. |
Go to Step 7. |
| 6 |
Replace the ECT sensor or repair the circuit as needed.
Is the repair complete? |
- |
System OK |
- |
| 7 |
- Check the ignition system output with a spark tester.
- Inspect the spark plugs for the proper heat range and gap.
- Check for the proper operation of the ignition controls.
Is the ignition system operating properly? |
- |
Go to Step 9. |
Go to Step 8. |
| 8 |
Repair or replace the ignition system components as needed.
Is the repair complete? |
- |
System OK |
- |
| 9 |
- Connect the scan tool to the Data Link Connector (DLC).
- Road test the vehicle at the speed of the complaint.
- Monitor the long term fuel trim reading from the scanner data stream.
Is the long term fuel trim reading above the value specified? |
20% |
Go to "DIAGNOSTIC AIDS " for DTC P0171: Fuel Trim System Lean Bank 1
. |
Go to Step 10. |
| 10 |
Check the fuel system pressure.
Is the problem found? |
310 kPa (45 psi) |
Go to Step 11. |
Go to Step 12. |
| 11 |
Repair or replace the fuel system components as needed.
Is the repair complete? |
- |
System OK |
- |
| 12 |
- Inspect for carbon buildup inside the engine.
- Remove the carbon with a top engine cleaner. Follow the instructions supplied with the product.
- Check the basic engine parts such as the camshaft, the cylinder head, the pistons, etc. for excessive wear.
- Replace any excessively worn parts.
Is the procedure complete? |
- |
Go to Step 13. |
- |
| 13 |
- Check the exhaust gas recirculation valve for proper operation.
- Check the air intake system for proper operation.
- Check the torque converter clutch operation and transaxle shift points.
- Check the service bulletins for Programmable Read-Only Memory (PROM) updates.
- Check the cylinder compression.
- Repair or replace any faulty components.
Are all checks and repairs complete? |
- |
System OK |
- |