Hard Starting

SYMPTOM DESCRIPTION:
Engine cranks OK, but does not start immediately. Will eventually start and run, but may die shortly after.



SYSTEM OR COMPONENT TO CHECK

COMPUTER INPUTS/OUTPUTS

CHECK:

- CONTROL MODULE: Defective ECM. Poor connections, or damaged wiring to ECM.
- ENGINE COOLANT TEMPERATURE SENSOR: Incorrect or defective sensor (wrong resistance value), poor connections or damaged wiring.
- IDLE VALVE: Stuck, restricted or partially closed idle air control valve, poor connections, damaged wiring or defective ECM.

Refer to COMPUTERS AND CONTROL SYSTEMS.



FUEL SYSTEM

CHECK:

- INJECTOR O-RINGS: Hardened or distorted (replace with green "Viton" O-rings).
- FUEL PUMP RELAY: Check for power at the fuel pump when ignition switch is in the start position and when the engine is running.
- FUEL SYSTEM RESIDUAL PRESSURE: Fuel system should retain a minimum residual pressure when the engine is not running. Insufficient residual pressure may be caused by faulty fuel pump check valve, leaking fuel injector(s), faulty pressure regulator or leaking hose connections.
- FUEL FILTER AND LINES: Filter(s) plugged or restricted. Leaking, pinched, or restricted fuel supply lines.
- FUEL PRESSURE REGULATOR: Defective, system pressure too low.
- MASS AIRFLOW SENSOR: Defective.
- FUEL QUALITY: Poor or contaminated fuel. Use of fuel not containing detergent additives causing deposits on intake valves and injector tips.
- RESTRICTED FUEL SUPPLY TO INJECTORS: Rubber particles clogging or restricting.




IGNITION SYSTEM

CHECK:

- SPARK PLUGS: Wet with water or fuel, improperly gapped, heavy deposits, cracked insulators, or worn electrodes.
- SPARK PLUG WIRES: Damaged insulation, arcing to cylinder head or to other wires, secondary resistance too high.
- IGNITION DISTRIBUTOR, CAP, AND ROTOR: Check for cracks, arcing, moisture, rust deposits or high resistance through rotor. Check for defective Camshaft Position Sensor.

Refer to IGNITION SYSTEM.