Hard Starting
***UPDATED BY TSB #259005, #289002, #259109, #259004, & #209001.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:
- CRANKSHAFT POSITION SENSOR: Damaged or defective crankshaft position sensor; missing, damaged, or severely worn flywheel teeth; accumulation of ferrous metal particles on sensor tip: poor connections or damaged wiring.
- CONTROL UNIT: Defective control unit. Poor connections, or damaged wiring to control unit.
- COOLANT TEMPERATURE SENSOR: Incorrect or defective sensor (wrong resistance value), poor connections or damaged wiring.
- IDLE VALVE: Stuck, restricted or partially closed idle stabilizer valve, poor connections, damaged wiring or defective control unit.
Refer to COMPUTERIZED ENGINE CONTROLS.
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. See FUEL PRESSURE REGULATOR (SYSTEM PRESSURE CHECKS) under COMPONENT TESTING. Insufficient residual pressure may be caused by faulty fuel pump check valve, leaking fuel injector(s), faulty system pressure regulator or leaking hose connections.
- COLD START VALVE: Clogged, stuck, poor connections or damaged wiring to control unit.
- FUEL QUALITY: Poor or contaminated fuel.
- FUEL FILTER AND LINES: Filter(s) plugged or restricted. Leaking, pinched, or restricted fuel supply lines, mini filter in fuel distributor inlet banjo bolt plugged or restricted.
- FUEL PRESSURE REGULATOR: Defective, system pressure too low.
- AIR FLOW SENSOR: Incorrectly adjusted sensor plate rest position or free-play; leaking control plunger (fuel leaking into air cleaner when engine is running).
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 hall sensor.
- IGNITION TIMING: Check distributor basic adjustment. See IGNITION TIMING under ADJUSTMENT PROCEDURES
Refer to IGNITION SYSTEMS.