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: - COOLANT TEMPERATURE SENSOR (CTS): Using a "Scan" tool compare coolant temperature with ambient temperature on a cold engine. If coolant temperature reading is 5 degrees more than or less than ambient air temperature on a cold engine, check for high resistance in coolant sensor circuit or sensor itself. Compare resistance value to the chart in COMPONENT TESTS under TESTING PROCEDURES.
- THROTTLE POSITION SENSOR (TPS): If a sticking throttle shaft or binding linkage causes a high TPS voltage (open throttle indication), the ECU will not control idle. Monitoring TPS voltage, a "Scan" tool and/or voltmeter should read less than 1.25 volts with throttle closed.
- IDLE SPEED STEPPER MOTOR/IDLE SPEED ACTUATOR MOTOR/SOLENOID-VACUUM THROTTLE POSITIONER: Refer to TESTING PROCEDURES/DIAGNOSTIC CHARTS/COMPONENT TESTING.
- No crank signal.



FUEL

Note: Fuel pump relay operation: Go to COMPONENT TESTS/RELAY TEST to check the operation of the fuel pump relay.

Check: - FUEL PRESSURE
- WATER CONTAMINATED FUEL
- FAULTY IN-TANK FUEL PUMP CHECK VALVE: This could allow the fuel in the lines to drain back to the tank after the engine is stopped. To check for this condition:
1. Ignition "OFF."
2. Disconnect fuel line at the filter.
3. Remove the tank filler cap.
4. Connect a radiator test pump to the fuel line and apply 103 kPa (15 psi) pressure. If the pressure will hold for 60 seconds, the check valve is OK.



IGNITION

Check: - Proper ignition voltage output with appropriate spark tester.
- Spark plugs, wet plugs, cracks, wear, improper gap, burned electrodes or heavy deposits.
- Bare and shorted wires.
- Moisture in distributor cap.
- Worn distributor shaft.
- Pickup coil connections.

Note: If engine starts, then immediately stalls, test pickup coil.



EMISSIONS

Check: - EGR SYSTEM: Valve operation.

NOTE: Refer to EMISSION CONTROLS for testing procedures.