Hard to 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 And Physical Checks" in Preliminary Checks. Testing and Inspection
- Make sure the driver is using the correct starting procedure.

SENSORS
- Check Engine Coolant Temperature (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. Refer to Engine Coolant Temperature / Specifications for sensor resistance values. Specifications

- Check Throttle Position (TP) Sensor - For a sticking throttle shaft or binding linkage or misadjusted. Refer to Throttle Position Sensor / Adjustments. Adjustments

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 Fuel Pressure Check. Chart A-7B Fuel System Pressure Check

Also refer to 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.
- Camshaft Position (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 Idle Air Control Valve Check. Chart C-2 Idle Air Control (IAC) System Check
- Check EGR system operation - refer to Chart C-7 EGR System Check. Chart C-7 EGR System Check
- Check Technical Service Bulletins for ECM updates.