Checks
| Action
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DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
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Preliminary Check
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Ignition System Checks
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| • | Check for adequate ignition coil voltage with a
J 26792 spark tester or equivalent. |
| • | Check the spark plugs for any of the following conditions: |
| - | Wet (fuel fouled) plugs. |
| - | A terminal screw that is bent or loose (rotate and pull). |
| - | A ceramic insulator that has cracks, carbon tracking or deposits (red or black dust) |
| - | A tip insulator that has cracks, carbon tracking, deposits (oil, carbon, glazing, fuel additive), or is loose (rattles). |
| - | A center electrode that is loose (wiggles side to side) |
| - | An incorrect spark plug gap that is too large or too small. |
| - | Platinum pads that are missing. |
| • | Check for crossfiring between spark plugs (distributor cap, spark plug wires, and proper routing of plug wires). |
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Engine Mechanical Checks
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| • | Check for any of the following engine mechanical problems: |
| - | Faulty hydraulic lifter assemblies |
| - | Broken or weak valve springs |
| - | Sticking or leaking valves |
| - | Incorrect or worn camshaft |
| • | Refer to Engine Mechanical. |
| • | Check the intake and exhaust system for casting flash or other restrictions. |
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Additional Check
| Check the EGR Valve for being open all the time. Refer to
Exhaust Gas Recirculation (EGR) System Diagnosis .
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