GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Sonoma Pickup - 4WD 🢒 Engine 🢒 Engine Controls - 2.2L 🢒 Detonation/Spark Knock

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 Symptoms .
    • Search for service bulletins.

Fuel System
    • Test for low fuel pressure. Refer to Fuel System Diagnosis .
    • Test for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect for a restricted fuel filter.
    • Inspect items that can cause an engine to run lean (Long Term FT significantly in the positive range). Refer to Diagnostic Aids for DTC P0171 Fuel Trim System Lean .

Ignition System
    • Inspect the spark plugs for proper heat range and reach. Refer to Spark Plug Replacement in Engine Electrical.
    • Confirm that the knock sensor (KS) system is not retarding timing.

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 of DEX-COOL or equivalent antifreeze coolant and water. Refer to Coolant Concentration Testing in Engine Cooling.

Engine Mechanical
    • Excessive oil in combustion chamber--Leaking valve seals. Refer to Engine Compression Test 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.
    • For incorrect basic engine parts. Inspect the following components:
       - Camshaft, refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical
       - Cylinder heads, refer to Cylinder Head Cleaning and Inspection in Engine Mechanical
       - Pistons, etc. Refer to Piston, Connecting Rod, and Bearing Cleaning and Inspection in Engine Mechanical

Additional Checks
  1. Inspect the Park/Neutral Position (PNP) switch input with a scan tool and the gear selector in drive or overdrive.
  2. Test TCC operation. TCC applying too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis in Automatic Transmission.
  3. If scan tool readings are normal and there are no engine mechanical malfunctions, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87 and re-evaluate vehicle performance.