Hard to Start

HARD START

Definition - Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.

PRELIMINARY CHECKS
- Perform the careful visual/physical checks.
- Make sure the driver is using the correct starting procedure.

SENSORS

Check ECT Sensor - Using a digital multimeter to measure resistance, compare ECT sensor resistance with ambient temperature on a cold engine.
- If ECT sensor resistance is greater than or less than ambient air temperature, check for high resistance in ECT sensor circuit or sensor itself. Compare resistance value to the "Diagnostic Aids" chart on DTC 14 or DTC 15 chart. DTC 15

Check TP Sensor - For a sticking throttle shaft or binding linkage or misadjusted.

FUEL SYSTEM

NOTE: Fuel pump relay operation - pump should "run" for 3 seconds when the ignition switch is turned to the "ON" position.

- Check fuel pressure, refer to Chart A-7B Chart A-7B Fuel System Pressure Check and On-Board Diagnostic System Check. Testing and Inspection
- Check for contaminated fuel.

IGNITION SYSTEM
- Check ignition system for:
- Proper ignition voltage output with J 26792 or equivalent.
- Spark plugs, wet plugs, cracks, wear, improper gap, burned electrodes or heavy deposits.
- Moisture, dust, cracks, burns, etc.
- Bare and shorted wires. Spray plug wires with fine water mist.
- Loose ignition coil connections.
- Faulty ECM and ignition grounds.
- CMP sensor resistance and connections.

ADDITIONAL CHECKS
- Check no crank signal - refer to On-Board Diagnostic System Check. Testing and Inspection
- Check IAC operation - refer to Chart C-2. Chart C-2 Idle Speed Control (ISC) Circuit
- Check EGR system operation - refer to Chart C-7. Chart C-7 EGR System Check
- Check Service Bulletins for ECM updates.