Hard Start

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Hard Start

Inspection	Action
DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run, or may start but immediately dies.
Preliminary Inspection	Refer to Symptoms - Engine Controls . Ensure the driver is using the correct starting procedure.
Sensor Inspection	Inspect the engine coolant temperature (ECT) sensor. Use the scan tool to compare the ECT with the ambient air temperature on a cold engine. If the coolant temperature reading is more than 5 degrees more or less than the ambient air temperature on a cold engine, inspect for a high resistance in the coolant sensor circuit or the sensor itself. Turn ON the ignition with the engine OFF. Observe the actual fuel rail pressure with a scan tool. The actual fuel rail pressure should be between 1.0-1.8 MPa. If it is not, inspect for high resistance in the fuel rail pressure (FRP) sensor circuits or the FRP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Inspect the crankshaft position (CKP) sensor reluctor wheel. Remove the 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.
Fuel System Inspection	Inspect the fuel pressure regulator 12-volt circuit for an intermittent short to ground. Observe the FRP Command percent while cranking. A range of 85-95 percent indicates a possible short to ground condition. Start the engine and command the fuel pressure to 160 MPa with a scan tool. If the actual fuel pressure does not reach 160 MPA, perform the Fuel System Diagnosis - High Pressure Side . Inspect the fuel supply to the fuel injection pump. Refer to Fuel System Diagnosis (Pickup) or Fuel System Diagnosis (Cab Chassis) . Inspect for a restricted fuel filter. Refer to Fuel System Diagnosis (Pickup) or Fuel System Diagnosis (Cab Chassis) . Inspect for air in the fuel system. Refer to Fuel System Diagnosis (Pickup) or Fuel System Diagnosis (Cab Chassis) . Inspect for external fuel leaks. Refer to Fuel Leaks (Outside of Engine) or Fuel Leaks (Inside of Engine) . Inspect for high engine oil level. Refer to Fuel in Engine Oil in Engine Mechanical - 6.6L. Inspect the fuel injectors. Refer to Fuel Injector Balance Test with Tech 2 (with Automatic Transmission) or Fuel Injector Balance Test with Tech 2 (with Manual Transmission) . At idle observe the FRP Regulator Fuel Flow Command parameter with a scan tool. If the FRP Regulator Fuel Flow Command is more than 2700 mm³ , perform the Fuel System Diagnosis - High Pressure Side . Inspect the fuel tank cap vent for proper operation.
Electrical System Inspection	Inspect the glow plug system for proper operation. Refer to Glow Plug System Diagnosis . Inspect for a slow cranking speed. Refer to Symptoms - Engine Electrical in Engine Electrical.
Air Intake System Inspection	Inspect the air cleaner and air intake ducts for a restrictions or leaks. Inspect for a restriction in turbocharger inlet duct. Inspect for a restriction or a leak in the intake manifolds.
Exhaust System Inspection	Inspect the exhaust system for a possible restriction. Refer to Restricted Exhaust in Engine Exhaust.
Engine Mechanical Inspection	Inspect the engine for the following conditions: Improper valve timing Bent pushrods Worn rocker arms-Refer to Valve Rocker Arm and Shaft Cleaning and Inspection in Engine Mechanical - 6.6L. Low engine compression-Refer to Engine Compression Test in Engine Mechanical - 6.6L. Broken or weak valve springs Worn camshaft lobes-Refer to Camshaft and Bearings Cleaning and Inspection in Engine Mechanical - 6.6L.
Additional Inspection	Inspect for an intermittent CKP signal. Refer to Intermittent Conditions . Compare the scan tool data at idle with the scan tool data list. Refer to Scan Tool Data List . Inspect the Service Bulletins for control module software updates.