Possible Causes & Corrections
WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Ensure vehicle has an actual problem.
- Inspect fuel quality.
- Inspect for smoke associated with the combustion noise.
- Inspect for obvious overheating problems.
- Inspect for a low engine coolant level.
- Inspect for any restricted air flow through the radiator.
- 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.
- Inspect Engine Coolant Temperature (ECT) sensor by using scan tool in order to compare ECT with ambient air temperature on a cold engine. If 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 Fuel Rail Pressure (FRP) sensor. Use scan tool to observe FRP with ignition on, with engine off. FRP reading should be 1.1-1.4 MPa. If FRP is not within this range, check for high resistance in the low reference or 5-volt reference circuits or the sensor, or a faulty sensor.
- Inspect for an intermittent Crankshaft Position (CKP) sensor signal.
- Inspect CKP sensor reluctor wheel. Remove 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.
- If excessive smoke is present, check for a stuck open fuel injector by performing the following procedure:
- Remove ignition 1 relay.
- Remove glow plugs.
- Crank engine while observing glow plug holes for fuel spray.
- Replace fuel injectors for cylinders that spray fuel.
- Check for fuel in the oil and proper oil level.
NOTE: Do not stand in front of glow plug holes while cranking engine. - Inspect for incorrect basic engine parts such as camshafts, cylinder heads, pistons, etc.
- Inspect for any excessive oil entering combustion chamber.
- Review Service Bulletins for control module software updates.
- Compare scan tool data at idle with scan tool data list. See PID VALUE CHARTS in PID VALUE CHARTS - SILVERADO & SIERRA article.