Hard to Start
SYMPTOM DESCRIPTIONEngine 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
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/SOLE-VAC THROTTLE POSITIONER: Refer to TESTING PROCEDURES/DIAGNOSTIC CHARTS/COMPONENT TESTING.
- No crank signal.
FUEL
Note: For 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 Valve operation.
Note: Refer to EMISSION CONTROLS for testing procedures.